Estelle Fischer

Rémy Cachon

Nathalie Cayot
email: nathalie.cayot@agrosupdijon.fr

a comparative review of nutritional, physicochemical, and sensory properties for food uses

Keywords: Pisum sativum, Glycine max, protein, functionality, enzymes, lipoxygenase

Introduction

Considering the current debate regarding the high level of animal protein in our diet, it is of interest to investigate meat substitutes. Today, it is known that animal proteins cause various problems. First, from an agronomic point of view, animal protein production uses large agricultural areas, consumes a lot of water and energy, produces a high quantity of methane and greenhouse gases, and depletes and pollutes agricultural areas, water, and air [START_REF] Bittman | Mark Bittman sur ce qui ne va pas dans notre alimentation[END_REF][START_REF] Chan | Protein[END_REF]. A diet rich in animal protein is also related to health problems such as an increase in diabetes and cardiovascular diseases [START_REF] Daniel | Trends in meat consumption in the USA[END_REF][START_REF] Song | A Prospective Study of Red Meat Consumption and Type 2 Diabetes in Middle-Aged and Elderly Women: The Women's Health Study[END_REF][START_REF] Walker | Public health implications of meat production and consumption[END_REF]. Moreover, people are now more concerned with animal welfare and increasing numbers are becoming vegetarians, vegans, or flexitarians [START_REF] Derbyshire | Flexitarian Diets and Health: A Review of the Evidence-Based Literature[END_REF][START_REF] Futuribles | Vigie Alimentation, les 10 transformations majeures[END_REF][START_REF] Kersche-Risch | Vegan diet: motives, approach and duration. Initial results of a quantitative sociological study[END_REF]. However, to achieve food security and protein intake for the growing world population, meat consumption needs to be reduced and thus meat substitutes need to be found [START_REF] De Boer | Meatless days" or "less but better"? Exploring strategies to adapt Western meat consumption to health and sustainability challenges[END_REF][START_REF] Onu | La population mondiale devrait atteindre 9,8 milliards en 2050 et 11,2 milliards en 2100[END_REF]. For all these reasons, it is important to develop more meat substitutes such as in cultured meat, insects, mycoproteins and, most importantly, vegetable proteins (American Dietetic Association, 2009;[START_REF] Datar | Possibilities for an in vitro meat production system[END_REF][START_REF] Elzerman | Consumer acceptance and appropriateness of meat substitutes in a meal context[END_REF][START_REF] Hoek | Replacement of meat by meat substitutes. A survey on person-and product-related factors in consumer acceptance[END_REF][START_REF] Verbeke | Profiling consumers who are ready to adopt insects as a meat substitute in a Western society[END_REF].

Until recently, vegetable proteins had been set aside because of their low protein content and a less favorable amino acid score compared to animal proteins (V. R. [START_REF] Young | Plant proteins in relation to human protein and amino acid nutrition[END_REF]. The total absorption and utilization of all the amino acids by the body is limited by the essential amino acid present in the lowest quantity, called the limiting amino acid. In addition, vegetable proteins are less digestible than animal proteins due to indigestible carbohydrate constituents, protein structures, and antinutritional factors [START_REF] Gilani | Effects of Antinutritional Factors on Protein Digestibility and Amino Acid Availability in Foods[END_REF].

However, associating different sources of protein resolves the issue of limiting amino acids. For example, associating a protein with a low Lysine content and a protein with a high Lysine content allows optimal absorption and utilization of the amino acid because the two proteins are complementary (American Dietetic Association, 2009). There are three main sources of vegetable protein: cereals, legumes, and oilseeds. Pulses are key to the development of vegetable protein as they are not major allergens and have numerous advantages [START_REF] Aluko | Emulsifying and Foaming Properties of Commercial Yellow Pea ( Pisum sativum L.) Seed Flours[END_REF]American Dietetic Association, 2009; V. R. [START_REF] Young | Plant proteins in relation to human protein and amino acid nutrition[END_REF]. Pulse crops are favorable for agricultural areas as the symbiotic bacteria on the root nodules can fix the nitrogen then release it in the ground so the plants do not require any additional nitrogenous fertilizer. This also helps the establishment of subsequent crops in the case of crop rotation. Furthermore, they contain high levels of essential amino acids, in particular lysine. Considering these advantages, it is important to develop more legume areas [START_REF] Bordat | Quel système alimentaire durable demain ? Illustration du projet TIGA de la Métropole[END_REF]Terres Inovia, 2017a;[START_REF] Univia | Pois -Les espèces cultivées -Cultures & utilisation -Terres Univia[END_REF].

Today, soybean (Glycine max) is the most widely used legume with 336 Mt produced annually worldwide and 140 000 t produced in France, mainly in the center and south (Terres [START_REF] Inovia | Guide de culture Soja[END_REF]Terres Univia, 2018). However, soybean has some negative aspects. Despite its advantages as a legume, most soybean production is intensive, which implies adding fertilizer and pesticides and using large amounts of water. In addition, due to the use of pesticides, 70% of soybean produced are plantpesticide GM crops, which can resist the addition of strong pesticides [START_REF] Inovia | Guide de culture Soja[END_REF]Terres Univia, 2018).

New legumes to substitute soybean are being investigated. A potentially great rival to soybean is the field pea (Pisum sativum), belonging to the Fabaceae and Papilionoïdeae phylogenetic group like soybean. Around 11 Mt of pea are produced every year in Europe and worldwide (Terres [START_REF] Univia | Pois -Les espèces cultivées -Cultures & utilisation -Terres Univia[END_REF]. France is one major producer in European Union with 600 000 t/year (Terres Inovia, 2017a;[START_REF] Univia | Pois -Les espèces cultivées -Cultures & utilisation -Terres Univia[END_REF]. Pea is widely used in crop rotation, which is highly beneficial for the soil as it helps the establishment of subsequent crops without plowing thanks to its small amount of chaff and early harvest that helps maintain the structure of the soil. Pea also increases the yield of the next crop in the case of crop rotations (+ 6-12 q/ha for wheat after pea compared to a wheat after wheat), reduces the environmental impact of the crop system by helping to control weeds and the biological processes within the crop rotations, as well as bringing financial gain (Terres Inovia, 2017a[START_REF] Inovia | Guide de culture Soja[END_REF][START_REF] Univia | Pois -Les espèces cultivées -Cultures & utilisation -Terres Univia[END_REF], 2018).

The aim of this study was, therefore, to compare different aspects of pea and soybean to determine if pea can substitute soybean. The first aspect is the composition and the impact on utilization, with a focus on functional properties. The second aspect is nutritional quality, with a focus on nutritional value and allergenicity. The third aspect is the composition and the impact on flavor, with a focus on substrates and enzymes responsible for flavor development.

Structure and physicochemical properties of soybean and pea proteins

Different studies compare the functional properties of soybean and pea proteins, but contradictory results have been found in the literature, possibly due to differences in protein purity, isolation methods, and seed variety [START_REF] Barac | Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean[END_REF].

A comparison of three articles, each comparing the functional properties of soybean and pea protein isolates purified using the same method, is presented in Table 1. In each reference column, different functional properties of soybean and pea protein isolates are compared. As these articles did not use the same determination methods and thus do not have comparable results, a color code is used to distinguish the functional properties; the best are presented in green and the worst in red. As can be seen, contradictory results are reported depending on the reference [START_REF] Aluko | Emulsifying and Foaming Properties of Commercial Yellow Pea ( Pisum sativum L.) Seed Flours[END_REF][START_REF] Barac | Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean[END_REF][START_REF] Fernàndez-Quintela | Composition and functional properties of protein isolates obtained from commercial legumes grown in northern Spain[END_REF]). As it is not possible to compare the functional properties of soybean and pea based on these contradictory data, comparing the protein structure, which is strongly related to the functional properties, may possibly provide more clues regarding the similarity of soybean and pea proteins.

Indeed, if proteins have the same primary sequences and 3D structures, they are more likely to have similar properties. In isolates or concentrates, the main proteins are globulins (7S and 11S). The soybean globulins are glycinin (11S) and conglycinin (7S), and the pea globulins are legumin (11S), vicilin, and convicilin (7S). The comparison of their 3D structures, as presented in Table 2, shows that soybean and pea proteins are really similar. The comparison of the protein sequences using Uniprot (UniProt, 2019) indicates a high percentage of identity, as shown in Table 2. The identity represents the correspondence between the two sequences. With an identity superior to 30%, the proteins can be considered as homologous [START_REF] Chifolleau | HMSN206 -Partie Alignement, Partie I-2 : Matrices de scores, BLAST, FASTA[END_REF][START_REF] Perrière | Recherche de similarités au moyen de BLAST[END_REF]. When the data is available, it is also possible to compare the beta-sheet and alpha-helix positions between the proteins. The comparison between Glycinin 1 and Legumin A shows that most of the beta-strands and alpha-helices are in the same position, as shown in Figure 1.

Consequently, as the 3D structures and the sequences of the proteins are similar, they may have essentially the same functional properties and thus may be used in the same ways. Soybean protein functionality is currently well understood whereas pea proteins are still in development. However, because of the similarities between the proteins, pea could potentially be used in the same way as soybean.

The literature partially confirms the similarity in protein structure and, therefore, functionality. Based on the solubility, and emulsifying and foaming properties of native and heat-treated soybean and pea isolates, soybean and pea have really close functional properties [START_REF] Barac | Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean[END_REF]. For example, the solubility of soybean and pea is very similar depending on the pH and the seed variety used. Furthermore, soybean and pea have similar patterns for the soluble protein composition. For the emulsifying properties, a strong impact of the genotype is observed. However, as the emulsifying property is strongly related to solubility, if the proteins have the same solubility the emulsifying property may also be similar. The similarity of the functional properties of the two proteins can also be seen with studies on products made with soybean and pea protein. For example, with yoghurt-like products made with soybean or pea protein, a similar texture is observed by sensorial analysis [START_REF] Yousseef | Compréhension et analyse alimentaire d'un mix fermenté de protéines animales / protéines végétales. Influence sur la physico-chimie et l'acceptabilité des produits obtenus[END_REF].

3 Nutritional quality of soybean and pea proteins

Nutritional value

To compare the nutritional aspects of soybean and pea, two indices can be compared: the DIAAS (lowest Digestible Indispensable Amino Acid Score) based on the amino acid reference ratios, and the PDCAAS index (Protein Digestibility Corrected Amino Acid Score). These indices are calculated as follows:

The PDCAAS is still currently the most widely used index but has some limitations [START_REF] Mathai | Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)[END_REF]. For example, the true fecal digestibility is used in the calculation whereas the ileal digestibility is more accurate. Moreover, PDCAAS values generally underestimate or overestimate the quantity of amino acids. For these reasons, the FAO recommends using the DIAAS, calculated with the individual ileal digestibility of the different indispensable amino acids. These parameters, with the percentage digestibility of the proteins, are compared between different samples in Table 3.

According to these data, soybean has a PDCAAS of 0.71 to 1.09, a DIAAS of 0.43 to 1.05, and a digestibility of 92 to 98.5 %, and pea has a PDCAAS of 0.49 to 0.96, a DIAAS of 0.45 to 0.822, and a digestibility of 69 to 99.0 %. The values vary depending on the calculation method and the protein form [START_REF] Hayes | Novel Proteins for Food, Pharmaceuticals, and Agriculture: Sources, Applications, and Advances[END_REF][START_REF] Hughes | Protein Digestibility-Corrected Amino Acid Scores (PDCAAS) for Soy Protein Isolates and Concentrate: Criteria for Evaluation[END_REF][START_REF] Mathai | Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)[END_REF][START_REF] Rutherfurd | Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats[END_REF]UNJURY®, 2019). Even in the same protein form (isolate or concentrate), the indices vary over a wide range depending on the calculation and the method used (on rats or pigs). Soybean and pea nutritional values seem close, even if soybean seems to have higher values (closer to the reference protein). However, if we consider the average pea PDCAAS (0.78), it still has a higher value than beans, rice, peanut or wheat that have a PDCAAS of 0.63, 0.53, 0.52, and 0.40, respectively [START_REF] Hughes | Protein Digestibility-Corrected Amino Acid Scores (PDCAAS) for Soy Protein Isolates and Concentrate: Criteria for Evaluation[END_REF]. It is also interesting to note that combinations of pea and cereal proteins are giving more favourable nutritional scores.

These differences in indices between soybean and pea may be due to two factors: the limiting amino acid and the digestibility factor. The amino acid content ratios of soybean and pea are close, as shown in Table 4 (% of amino acid/total amino acid), but some essential amino acids are present in lower quantities in pea than in soybean, which would explain some differences [START_REF] Carrera | Amino acid composition of soybean seeds as affected by climatic variables[END_REF]Leterme, Monmart, & Baudart, 1990). The digestibility factor is also slightly different. As seen in Table 3, the digestibility factors of soybean and pea seem to vary depending on the protein form (isolate, concentrate) and protein content (globulins, albumins), with pea having one of the lowest digestibility factors [START_REF] Hayes | Novel Proteins for Food, Pharmaceuticals, and Agriculture: Sources, Applications, and Advances[END_REF][START_REF] Hughes | Protein Digestibility-Corrected Amino Acid Scores (PDCAAS) for Soy Protein Isolates and Concentrate: Criteria for Evaluation[END_REF][START_REF] Mathai | Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)[END_REF][START_REF] Rutherfurd | Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats[END_REF]UNJURY®, 2019).

With a lower content of sulphur amino acids and less digestible protein, pea has a lower nutritional value than soybean. However, depending on the product form and content, pea protein can still be a good substitute as regards this aspect.

Allergenicity

Besides its isoflavone content, whose impact on health is still under debate, soybean is sometimes set aside because of its allergenicity. The EFSA classify plant allergens into four main families according to sequence homology, 3D structure, and function: prolamins, cupins, profilins, and Bet v1 (EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), 2014).

Soybean is a major allergen, with 30 IgE-binding proteins, leading to all stages of allergic reactions.

These 30 proteins include different families: cupins with 7S (vicilin -Gly m5), 11S (legumin -Gly m6), 15S, and 2S globulins; prolamin (hydrophobic protein Gly m1 and Gly m2); pollens peers; oleosin; 2S albumin, and P34 protease. Some of these are major allergens: β-conglycinin (Gly m5), glycinin (Gly m6), and P34 protease (Glym Bd 30 kDa) (Gomez-Andre, [START_REF] Gomez-Andre | Un allergène émergent : le soja[END_REF]. Soybean is also one of the main allergens involved in FPIES (Food Protein-Induced Enterocolitis Syndrome), a non-IgE allergic reaction characterized by vomiting and hemorrhagic diarrhea [START_REF] Bidat | Syndrome d'entérocolite induit par les protéines alimentaires (SEIPA)[END_REF]. Nowadays, soybean allergies are more prevalent due to the increasing use of soybean as an additive in foods.

The literature suggests pea is less allergenic than soybean, which may facilitate its food use. First of all, pea seems to be very rarely involved in FPIES [START_REF] Bidat | Syndrome d'entérocolite induit par les protéines alimentaires (SEIPA)[END_REF] and is not a major allergen [START_REF] Aluko | Emulsifying and Foaming Properties of Commercial Yellow Pea ( Pisum sativum L.) Seed Flours[END_REF]. Pea contains less allergenic factors but its allergenicity, as in soybean, is caused by 7S globulin (vicilin and convicilin) [START_REF] Sanchez-Monge | Vicilin and convicilin are potential major allergens from pea[END_REF], with the major allergen being convicilin [START_REF] Dreyer | Scientific Opinion on the evaluation of allergenic foods and food ingredients for labelling purposes[END_REF].

According to the EFSA, the immunogenicity of an allergen is partially related to the structural features of the proteins and their biological activity. Soybean and pea proteins are really close, as discussed above, so their major allergens are supposedly the same: 7S and 11S globulins (EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), 2014). Based on ANSES reports, pea can now be considered as an emergent allergen [START_REF] Cérou | De nouveaux allergènes émergents selon l'Anses / Qualité -Process Alimentaire, le magazine des industriels de l'agroalimentaire[END_REF]. Although pea seems less allergenic than soybean, as the same proteins are involved in allergic reactions, pea could become as allergenic as soybean.

To obtain more clues as to the allergenic potential of pea, the number of soybean and pea allergens identified in databases was compared. COMPARE (COMprehensive Protein Allergen Resource) (COMPARE Allergen Database, 2019) and Base AllergenOnline (Base AllergenOnline, 2019) were used. For pea (Pisum sativum), four allergens were found in COMPARE and seven in Base AllergenOnline. For soybean (Glycine max), 41 allergens were found in COMPARE and 42 in Base AllergenOnline. From the allergens identified, pea seems less allergenic than soybean. However, pea allergenicity is still being investigated; some soybean allergens may be present in pea. To verify this point, soybean allergens were firstly classified by "family": 2S albumins, glycinin, β-conglycinin (alpha, alpha' and beta subunits), trypsin inhibitor, P34 protease, and profilin. Then, some key allergens in each family were investigated in pea using a BLAST search of the allergen sequences from COMPARE (COMPARE Allergen Database, 2019) (FASTA format) on Uniprot (UniProt, 2019) (e threshold <1, BLOSUM62 matrix, gapped true).

The 2S albumin, trypsin inhibitor, and profilin allergens were not found in pea and nor was one of the major allergens (Major Gly 50kDa allergen). However, the glycinin allergen (glycinin) was found in the pea legumin sequences, with 43.00 % to 55.90 % identity. The β-conglycinin subunit allergens were also found in the pea vicilin and convilin sequences with 40.20 % to 57.30 % identity.

Thus, according to current knowledge, pea seems to contain fewer allergens than soybean, with no 2S albumin, trypsin inhibitor, or profilin allergens. Major pea allergens are vicilin and convicilin.

Development of the volatile fraction in pea and soybean proteins

Raw soybean and pea are compared here. The composition of the matrix has an impact on flavor. The typical legume off-flavor, known as "beany", "green" or "earthy/musty" [START_REF] Murat | Etude de la fraction volatile d'extraits protéiques de pois : propriétés et interactions avec le milieu[END_REF][START_REF] Vara-Ubol | Sensory characteristics of chemical compound potentially associated with beany aroma in foods[END_REF], is the combination of different volatile compounds belonging to different chemical families such as aldehydes, ketones or alcohols.

Many of these compounds are typically found in legumes [START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF] and are generated via different pathways. The enzymatic and non-enzymatic degradation of lipids, amino acids, and peptides are primarily responsible for off-flavor development [START_REF] Angerosa | Biogeneration of Volatile Compounds in Virgin Olive Oil: Their Evolution in Relation to Malaxation Time[END_REF][START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF]. Thus, investigating the substrates in these reactions (lipids and amino acids) and the enzymes involved in the enzymatic pathways is of interest to estimate the "beany" flavor development potential. For example, if the matrix has more substrates or enzymes, the potential of developing a "beany" flavor or a stronger "beany" attribute is higher.

Substrates

Lipids

Lipids are the main substrates in the production of different aldehydes and ketones that lead to different alcohols. The different lipids lead to different volatile compounds. The lipid content in Soybean is approximately 20 %, whereas the lipid content in pea is only 2 % [START_REF] Eriksson | Pea Lipoxidase, Distribution of Enzyme and Substrate in Green Peas[END_REF][START_REF] Murat | Etude de la fraction volatile d'extraits protéiques de pois : propriétés et interactions avec le milieu[END_REF][START_REF] Triboi | Productivity and grain or seed composition: a new approach to an old problem-invited paper[END_REF][START_REF] Young | Protein, Fiber, and Lipid content of vegetable soybean[END_REF]. The different fatty acids present in soybean and pea are presented in Table 5.

The most important fatty acids in soybean are linoleic acid, oleic acid, and linolenic acid [START_REF] Grela | Fatty acid composition and tocopherol content of some legume seeds[END_REF][START_REF] Shoemaker | Fatty acid composition of soybean (Glycine max (L.) merr.) somatic embryos[END_REF][START_REF] Sultan | Oil content and fatty acid composition of soybean (Glysine max L.) genotypes evaluated under rainfed conditions of Kashmir Himalayas in 910-915[END_REF]. The most important fatty acids in pea are linoleic acid, oleic acid, palmitic acid, and linolenic acid [START_REF] Eriksson | Pea Lipoxidase, Distribution of Enzyme and Substrate in Green Peas[END_REF][START_REF] Grela | Fatty acid composition and tocopherol content of some legume seeds[END_REF][START_REF] Murat | Etude de la fraction volatile d'extraits protéiques de pois : propriétés et interactions avec le milieu[END_REF][START_REF] Murcia | Fatty acid composition of pea (Pisum sativum) L. var. Citrina) during growth[END_REF]. Among the fatty acids, the unsaturated ones are of interest because they are the main substrates of volatile compounds. For example, linoleic acid leads to the formation of hexanal, and oleic acid to the formation of octanal [START_REF] Frankel | Volatile lipid oxidation products[END_REF][START_REF] Gargouri | Voie de la lipoxygénase : valorisation d'huiles végétales et biosynthèse de flaveurs[END_REF][START_REF] Murray | Volatile Flavor Components from Green Peas (Pisum Sativum)..: 1. Alcohols in Unblanched Frozen Peas[END_REF][START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF][START_REF] Snyder | Comparison of gas chromatographic methods for volatile lipid oxidation compounds in soybean oil[END_REF].

As can be seen in Table 5, the fatty acid profiles of soybean and pea are similar. However, the lipid content in soybean is higher than in pea, which can lead to more lipid degradation. Consequently, soybean may develop more volatile and off-flavor compounds.

However, enzymatic and non-enzymatic oxidation of lipids starts really early and rapidly after the harvest. The off-flavor compounds formed are perceptible at very low levels (in the order of ppb and ppm). Moreover, the typical "beany" off-flavor is generally expressed when the compound is present between 1 and 10 ppm in the matrix [START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF][START_REF] Vara-Ubol | Sensory characteristics of chemical compound potentially associated with beany aroma in foods[END_REF]. Therefore, even the smallest quantity of lipids is enough to develop the strong, characteristic off-flavor of legumes, as is the case in pea [START_REF] Angerosa | Biogeneration of Volatile Compounds in Virgin Olive Oil: Their Evolution in Relation to Malaxation Time[END_REF][START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF][START_REF] Schindler | Lactic fermentation to improve the aroma of protein extracts of sweet lupin (Lupinus angustifolius)[END_REF][START_REF] Schindler | Improvement of the Aroma of Pea ( Pisum sativum ) Protein Extracts by Lactic Acid Fermentation[END_REF]. Thus, even the 2% of lipids in pea are enough to develop a strong off-flavor. Maturity and moisture content can also have an impact. For example, the low moisture content in mature soybean limits oxygen diffusion in the center of the soybean (cotyledon) and consequently lipid degradation, whereas the high moisture content in fresh immature peas facilitates the reaction [START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF].

Amino acids

Amino acids are the second main substrates of volatile compounds. The amino acid profiles of pea and soybean are presented in Table 4 (g of amino acid/100g of protein).

Proteolysis directly contributes to off-flavor development by releasing peptides and amino acids [START_REF] Marilley | Flavours of cheese products: metabolic pathways, analytical tools and identification of producing strains[END_REF]. Some amino acids are the substrates of some strong volatile flavor compounds. For example, leucine, isoleucine, and valine are the main precursors of branched aldehydes such as 2-and 3-methylbutanal [START_REF] Angerosa | Influence of malaxation temperature and time on the quality of virgin olive oils[END_REF][START_REF] Lee | Comparative Volatile Profiles in Soy Sauce According to Inoculated Microorganisms[END_REF][START_REF] Murray | The volatiles of off-flavoured unblanched green peas (Pisum sativum)[END_REF]; Rodríguez-Bernaldo De Quirós, López-Hernández, González-Castro, De la [START_REF] De Quirós | Comparison of volatile components in raw and cooked green beans by GC-MS using dynamic headspace sampling and microwave desorption[END_REF]. Sulfurous compounds develop from the degradation of sulfurous amino acids, mainly methionine [START_REF] Marilley | Flavours of cheese products: metabolic pathways, analytical tools and identification of producing strains[END_REF][START_REF] De Quirós | Comparison of volatile components in raw and cooked green beans by GC-MS using dynamic headspace sampling and microwave desorption[END_REF]. The breakdown of amino acids also leads to the formation of pyrazines. The process involves different amino acids such as alanine, leucine, serine, and threonine [START_REF] Murray | The volatiles of off-flavoured unblanched green peas (Pisum sativum)[END_REF][START_REF] Shu | Pyrazine Formation from Serine and Threonine[END_REF][START_REF] Wang | Formation of pyrazines from thermal treatment of some aminohydroxy compounds[END_REF].

Unlike lipid degradation, amino acid degradation is slow and takes place throughout the product's life cycle. As shown in table 4 (g of amino acid/100g of protein), pea contains more amino acids involved in off-flavor development (leucine, serine, and threonine). For example, even if the ratios of leucine are similar in pea and soy, pea contains more leucine (6.6 g / 100g instead of 3.5 g /100g in soybean). As a consequence, pea can lead to the development of more volatile compounds and thus a stronger off-flavor.

Enzymes

Enzymes involved in the enzymatic oxidation of lipids are of primary interest because they lead to different volatile compounds. Two main enzymes are investigated here: lipoxygenase and hydroperoxide lyase. Lipase breaks down triglycerides into free fatty acids. Then, lipoxygenase transforms the different free fatty acids into fatty acid hydroperoxide. Hydroperoxide lyase then cuts the fatty acid hydroperoxides into acids and volatile compounds such as aldehydes [START_REF] Gargouri | Voie de la lipoxygénase : valorisation d'huiles végétales et biosynthèse de flaveurs[END_REF][START_REF] Moreno | Chapter 3 Must Aromas ; 5 Substrances derived from treatments prior to fermentation ; 5.1 Synthesis[END_REF]. Depending on the substrate specificity and the cleavage site of the enzyme, different compounds are formed. There are, therefore, different isoenzymes of lipoxygenase and hydroperoxide lyase.

Lipoxygenase

Lipoxygenase activity (EC 1.13.11.12) catalyzes fatty acid oxidation into fatty acid hydroperoxides (HPOD) by adding a hydroperoxide functional group to the carbon chain. Depending on the isoenzyme, lipoxygenase introduces the group at carbon 9, 10 or 13 to form the corresponding 9-, 10or 13-fatty acid HPOD [START_REF] Lumen | Formation of volatile flavor compounds in green beans from linoleic anc linolenic acids[END_REF][START_REF] Pinsky | Lipoxygenase content and antioxidante activity of some fruits and vegetables[END_REF][START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF]. A strong lipoxygenase is found in legumes, and particularly in Fabaceae, and high levels of HPOD are formed even with a low lipid content [START_REF] Fauconnier | Assessment of lipoxygenase activity in seed extracts from 35 plant species[END_REF][START_REF] Veldink | Plant Lipoxygenases[END_REF].

Differences in the molecular masses and amino acid composition of soybean and pea lipoxygenase [START_REF] Eriksson | Lipoxygenase from peas, purification and properties of the enzyme[END_REF] indicate different isoenzymes.

According to the literature, soybean contains three or four isoenzymes (LOX-1, LOX-2, LOX-3, and LOX-4) with different optimum pHs. By combining the various references, an overview of the properties of lipoxygenase isoenzymes in soybean is proposed in Table 6.

LOX-1 has an optimum pH of nine to ten and LOX-2, LOX-3, and LOX-4 have an optimum pH of six to seven [START_REF] Eriksson | Lipoxygenase from peas, purification and properties of the enzyme[END_REF][START_REF] Eskin | Biochemistry of lipoxygenase in relation to food quality[END_REF][START_REF] Fauconnier | Assessment of lipoxygenase activity in seed extracts from 35 plant species[END_REF][START_REF] Grosch | Differences in the amount and range of volatile carbonyl compounds formed by lipoxygenase isoenzymes from soybeans[END_REF][START_REF] Kalua | Olive oil volatile compounds, flavour development and quality: A critical review[END_REF][START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF][START_REF] Veldink | Plant Lipoxygenases[END_REF]. More 13-HPOD is formed at pH 9, therefore, LOX-1 working at pH 9 should be a 13-LOX with an oxygen being added to carbon 13 of the fatty acids [START_REF] Fauconnier | Assessment of lipoxygenase activity in seed extracts from 35 plant species[END_REF][START_REF] Pinsky | Lipoxygenase content and antioxidante activity of some fruits and vegetables[END_REF]. Equivalent levels of 13-and 9-HPOD are formed at pH 6, therefore, LOX-2 and LOX-3 are two different isoenzymes, 13-LOX and 9-LOX, respectively [START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF]. According to [START_REF] Matoba | Contribution of hydroperoxide lyase activity to n-hexanal formation in soybean[END_REF], LOX-2 is mainly responsible for the formation of hexanal, a 13-HPOD product of linoleic acid and is thus a 13-LOX. The remaining LOX-3 is, therefore, a 9-LOX. But, according to [START_REF] Grosch | Differences in the amount and range of volatile carbonyl compounds formed by lipoxygenase isoenzymes from soybeans[END_REF], LOX-3 produces hexenal, a 13-HPOD product of linolenic acid. Two hypotheses are possible here: LOX-2 is a 13-LOX and LOX-3 is a 9-LOX, or LOX-2 and 3 are both 9-and 13-LOX possibly with different substrate specificities. According to the enzyme properties such as the impact of Ca 2+ on enzyme activity [START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF], it is more likely that LOX-2 and LOX-3 are different. LOX-4 is unidentified.

According to the literature, pea contains three, four or five isoenzymes (LOX-1, LOX-2, LOX-3, LOX-4, and LOX-5) [START_REF] Eskin | Biochemistry of lipoxygenase in relation to food quality[END_REF][START_REF] Veldink | Plant Lipoxygenases[END_REF]. By combining the various references, an overview of the properties of isoenzymes in pea is proposed in Table 6.

Identifying the different properties of these isoenzymes is a bit harder in pea because less work has been done on this topic. As 9-and 13-HPOD are found, pea contains 9-LOX and 13-LOX. Different optimum pHs are found. At pH six to seven, 9-and 13-HPOD are found suggesting two isoenzymes working at this pH (9-LOX and 13-LOX). 13-HPOD is also found at a pH above eight, suggesting a 13-LOX working at a pH above eight [START_REF] Matsui | Linoleic Acid 10-Hydroperoxide as an Intermediate during Formation of 1-Octen-3-ol from Linoleic Acid in Lentinus decadetes[END_REF][START_REF] Veldink | Plant Lipoxygenases[END_REF]. Therefore, it is proposed that LOX-1 is a 13-LOX at a pH above eight, LOX-2 is a 13-LOX at pH six to seven, and LOX-3 is a 9-LOX at pH six to seven, as in soybean. At least one of the enzymes is heat-stable because activity is still observed after heat treatment [START_REF] Rhee | Lipid Oxidation in Frozen Vegetables in Relation to Flavor Change[END_REF]. It makes sense to identify the heat-stable enzyme as LOX-1, as in soybean. The two isoenzymes identified by [START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF] are inhibited by Ca 2+ but, because five isoenzymes are identified here, it is not possible to know which isoenzymes are inhibited by Ca 2+ . 10-HPOD is also present in pea [START_REF] Matsui | Linoleic Acid 10-Hydroperoxide as an Intermediate during Formation of 1-Octen-3-ol from Linoleic Acid in Lentinus decadetes[END_REF].

As far as we know, no 10-LOX responsible for the formation of 10-HPOD has been identified in pea but exists in other matrices [START_REF] Assaf | 1-Octen-3-ol and 13, hydroperoxylinoleate are products of distinct pathways in the oxidative breakdown of linoleic acid by Pleurotus pulmonarius[END_REF][START_REF] Badenhop | The formation of 1-octen-3-ol in soybeans during soaking[END_REF][START_REF] Husson | Effect of linoleic acid induction on the production of 1-octen-3-ol by the lipoxygenase and hydroperoxide lyase activities of Penicillium camemberti[END_REF][START_REF] Matsui | Linoleic Acid 10-Hydroperoxide as an Intermediate during Formation of 1-Octen-3-ol from Linoleic Acid in Lentinus decadetes[END_REF][START_REF] Wurzenberger | The formation of 1-octen-3-ol from the 10-hydroperoxide isomer of linoleic acid by a hydroperoxide lyase in mushrooms (Psalliota bispora)[END_REF]. Thus, it is proposed that one of the remaining isoenzymes is a 10-LOX, called here LOX-5. 10-LOX has an optimum pH of six, is inactive at pH eight, and is heat-labile [START_REF] Assaf | 1-Octen-3-ol and 13, hydroperoxylinoleate are products of distinct pathways in the oxidative breakdown of linoleic acid by Pleurotus pulmonarius[END_REF][START_REF] Matsui | Linoleic Acid 10-Hydroperoxide as an Intermediate during Formation of 1-Octen-3-ol from Linoleic Acid in Lentinus decadetes[END_REF][START_REF] Wurzenberger | The formation of 1-octen-3-ol from the 10-hydroperoxide isomer of linoleic acid by a hydroperoxide lyase in mushrooms (Psalliota bispora)[END_REF]. LOX-4 is unidentified.

The comparison of the lipoxygenase profiles of soybean and pea indicates that the catalytic activities of the isoenzymes are similar. However, because of the differences in the amino acid composition of some isoenzymes, the substrate specificity may not be the same. These conclusions regarding pea isoenzymes are in accordance with the first conclusions made [START_REF] Yoon | Some properties of pea lipoxygenase isoenzymes[END_REF]: two isoenzymes working at acidic-neutral pH, close to soybean LOX-2 and LOX-3, and another isoenzyme working at alkaline pH, close to soybean LOX-1.

In addition to this comparison, differences between the various soybean and pea isoenzymes may also be observed regarding the substrate specificity of the isoenzymes. For example, all the isoenzymes do not exhibit activity on linoleic acid and methyl linoleate [START_REF] Eskin | Biochemistry of lipoxygenase in relation to food quality[END_REF][START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF]. Moreover, because isoenzymes forming mixtures of 9-and 13-HPOD also exist, one or more of the isoenzymes listed may be of this kind. This 9-and 13-LOX may be one of the isoenzymes identified but with a higher specificity for 9-HPOD or 13-HPOD or may be the last unidentified isoenzyme [START_REF] Yoon | Some properties of pea lipoxygenase isoenzymes[END_REF]).

Moreover, it seems that pea contains more isoenzymes than soybean and thus has a stronger enzymatic oxidation activity. For example, pea seems to contain a 10-LOX and soybean does not. 10-HPOD may be formed in soybean, but via autoxidation pathways more than enzymatic pathways and therefore more 10-HPOD products such as 1-octen-3-ol may be formed in pea [START_REF] Husson | Effect of linoleic acid induction on the production of 1-octen-3-ol by the lipoxygenase and hydroperoxide lyase activities of Penicillium camemberti[END_REF].

Hydroperoxide Lyase

Fatty acid hydroperoxides are cleaved by hydroperoxide lyase to form a volatile compound and an acid. Hydroperoxide lyase catalyzes the cleavage of the bond between the hydroperoxide functional group and the adjacent E double-bond. Hydroperoxide lyases can be divided into two groups: heterolytic and homolytic and depending on their cleavage site. Thus, 9-HPL cleaves 9-HPOD, 13-HPL cleaves 13-HPOD but also 9 and 13-HPL cleave 9 and 13-HPOD [START_REF] Gargouri | Coupled Hydroperoxide Lyase and Alcohol Dehydrogenase for Selective Synthesis of Aldehyde or Alcohol[END_REF][START_REF] Kondo | An enzymatic formation of 13-oxo-trideca-9,11dienoic acid from 13-hydroperoxylinolenic acid by a homolytic hydroperoxide lyase in elicitor-treated soybean cotyledons[END_REF].

In soybean, the 13-pathway is predominant. Products of 9-HPOD are only found in traces. Thus, 13-HPL is the main HPL present in soybean [START_REF] Matoba | Contribution of hydroperoxide lyase activity to n-hexanal formation in soybean[END_REF]. In pea, many HPOD degradation products are found, suggesting the presence of the two isoenzymes (9-HPL and 13-HPL) contrary to other legumes such as beans in which only 13-HPL is found. Moreover, more 13-HPOD products are found, indicating the presence of the strongest 13-HPL activity or the presence of a 9 and 13-HPL with a higher affinity for 13-HPOD [START_REF] Hornostaj | Purification of hydroperoxide lyase from pea seeds[END_REF][START_REF] Kalua | Olive oil volatile compounds, flavour development and quality: A critical review[END_REF]. In addition, with the presence of a lot of 10-HPOD degradation products, it is highly possible that pea also contains a 10-HPL.

The HPL activity in pea is optimal around pH six, but the 13-activity is less sensitive to an increase in pH than the 9-activity, which is reduced by half at a pH above seven. These pH characteristics may indicate, as with lipoxygenases, different 13-HPL: one with an optimum pH of six and one with an optimum pH above seven [START_REF] Hornostaj | Purification of hydroperoxide lyase from pea seeds[END_REF].

The comparison of the hydroperoxide lyase profiles of soybean and pea clearly shows that the isoenzymes are different. Only one isoenzyme -13-HPL -is predominant in soybean whereas at least two -9-HPL and 13-HPL -are found in pea. With this information, it is clear that more products resulting from the degradation of HPOD by HPL are produced in pea than in soybean and thus, a higher number of different volatile compounds are found in pea.

Conclusion

Beyond its agronomic advantages, pea has some advantages because it is less allergenic than soybean.

The two legumes have many functional and nutritional similarities. However, pea has some particularities that could lead to more off-flavor and thus, a less appreciated product. For example, pea contains more amino acids involved in off-flavor development and more enzymes involved in lipid oxidation that contribute to the "beany" attribute. As a result of these particularities, pea may contain particular aromatic compounds responsible for the "beany" flavor and also higher quantities of some of these compounds. Moreover, some work is still needed to characterize the pea off-flavor and the odorant compounds involved. Work must be conducted to control and to correct the pea off-flavor in order to produce acceptable food products for consumers. Table 1: Comparison of functional properties of soybean and pea protein isolates purified using the same method [START_REF] Aluko | Emulsifying and Foaming Properties of Commercial Yellow Pea ( Pisum sativum L.) Seed Flours[END_REF][START_REF] Barac | Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean[END_REF][START_REF] Fernàndez-Quintela | Composition and functional properties of protein isolates obtained from commercial legumes grown in northern Spain[END_REF].

Figure caption

References [1] [START_REF] Fernàndez-Quintela | Composition and functional properties of protein isolates obtained from commercial legumes grown in northern Spain[END_REF], [START_REF] Yousseef | Compréhension et analyse alimentaire d'un mix fermenté de protéines animales / protéines végétales. Influence sur la physico-chimie et l'acceptabilité des produits obtenus[END_REF] [START_REF] Aluko | Emulsifying and Foaming Properties of Commercial Yellow Pea ( Pisum sativum L.) Seed Flours[END_REF] [START_REF] Barac | Comparative study of the functional properties of three legume seed isolates: adzuki, pea and soy bean[END_REF]; Units used for the functional properties may be different for the three references. Details are given in the Cosucra, 2017;[START_REF] Hayes | Novel Proteins for Food, Pharmaceuticals, and Agriculture: Sources, Applications, and Advances[END_REF][START_REF] Hughes | Protein Digestibility-Corrected Amino Acid Scores (PDCAAS) for Soy Protein Isolates and Concentrate: Criteria for Evaluation[END_REF][START_REF] Mathai | Values for digestible indispensable amino acid scores (DIAAS) for some dairy and plant proteins may better describe protein quality than values calculated using the concept for protein digestibility-corrected amino acid scores (PDCAAS)[END_REF][START_REF] Rutherfurd | Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats[END_REF]UNJURY®, 2019) Legend: calculation 1: for infant (0 to 6 months), 2: for child (6 months to 3 years), 3: for preschool children (2 to [START_REF] Carrera | Amino acid composition of soybean seeds as affected by climatic variables[END_REF]Leterme et al., 1990). Essential amino acids are in bold. Other includes: C 10:0 , C 12:0 , C 20:0 , C 20:1 , C 22:0 , C 22:1 and unknown acids.

Table 6: Proposed overview of the different soybean and pea lipoxygenase isoenzymes [START_REF] Assaf | 1-Octen-3-ol and 13, hydroperoxylinoleate are products of distinct pathways in the oxidative breakdown of linoleic acid by Pleurotus pulmonarius[END_REF][START_REF] Eriksson | Lipoxygenase from peas, purification and properties of the enzyme[END_REF][START_REF] Eskin | Biochemistry of lipoxygenase in relation to food quality[END_REF][START_REF] Fauconnier | Assessment of lipoxygenase activity in seed extracts from 35 plant species[END_REF][START_REF] Gargouri | Voie de la lipoxygénase : valorisation d'huiles végétales et biosynthèse de flaveurs[END_REF][START_REF] Grosch | Differences in the amount and range of volatile carbonyl compounds formed by lipoxygenase isoenzymes from soybeans[END_REF][START_REF] Husson | Effect of linoleic acid induction on the production of 1-octen-3-ol by the lipoxygenase and hydroperoxide lyase activities of Penicillium camemberti[END_REF][START_REF] Kalua | Olive oil volatile compounds, flavour development and quality: A critical review[END_REF][START_REF] Lumen | Formation of volatile flavor compounds in green beans from linoleic anc linolenic acids[END_REF][START_REF] Matoba | Contribution of hydroperoxide lyase activity to n-hexanal formation in soybean[END_REF][START_REF] Matsui | Linoleic Acid 10-Hydroperoxide as an Intermediate during Formation of 1-Octen-3-ol from Linoleic Acid in Lentinus decadetes[END_REF][START_REF] Moreno | Chapter 3 Must Aromas ; 5 Substrances derived from treatments prior to fermentation ; 5.1 Synthesis[END_REF][START_REF] Pinsky | Lipoxygenase content and antioxidante activity of some fruits and vegetables[END_REF][START_REF] Rackis | Flavor problems of vegetable food proteins[END_REF][START_REF] Rhee | Lipid Oxidation in Frozen Vegetables in Relation to Flavor Change[END_REF][START_REF] Sessa | Biochemical aspects of lipid-derived flavors in legumes[END_REF][START_REF] Veldink | Plant Lipoxygenases[END_REF][START_REF] Wurzenberger | The formation of 1-octen-3-ol from the 10-hydroperoxide isomer of linoleic acid by a hydroperoxide lyase in mushrooms (Psalliota bispora)[END_REF][START_REF] Yoon | Some properties of pea lipoxygenase isoenzymes[END_REF])

Lipoxygenase

Figure 1 :

 1 Figure 1: Sequence alignment for glycinin 1 (GlyG1-SOY) and legumin A (LegA-PEA).

Figure 1

 1 Figure 1

Table 2 :

 2 table. 1 : Oil droplet size-d 3,2(µm). Comparison of structure and primary sequence of soybean and pea 11S and 7S protein fractions.3D models from SWISS-MODEL[START_REF] Bienert | The SWISS-MODEL Repository-new features and functionality[END_REF][START_REF] Guex | Automated comparative protein structure modeling with SWISS-MODEL and Swiss-PdbViewer: A historical perspective[END_REF][START_REF] Swiss-Model | SWISS-MODEL[END_REF][START_REF] Waterhouse | SWISS-MODEL: homology modelling of protein structures and complexes[END_REF]. Percentage of identity obtained by sequence comparison (SC) with the Uniprot Align function (UniProt, 2019).

	Pea C = Calvedon Variety, Pea P = Provansalac Variety, Soybean B = Bosa Variety, Soybean O = Olga Variety, Soybean DB = Black Domestic Variety;
	nd = not determined;
	a,b,c = letters represent the statistical differences based on the original article; for a given reference, samples with the same letters are not statistically
	different;
	best functional properties, worst functional properties, medium or equal functional properties.

Table 3 :

 3 DIAAS, PDCAAS, and digestibility factors of soybean and pea extracts (

Table 4 :

 4 5 years), 4: for children, adolescents, and adults (> 3 years). Nd = not determined. Amino acid composition of soybean and pea, in % of amino acid/total amino acid and in g/100g,

						DIAAS			PDCAAS
	Protein		Reference	Calculated on	1	2	4	1	2	3	4	Digestibility (%)
	Isolate	Pisane	Hayes (2018) & Cosucra (2017)	unknown		nd			0.96			98
		Nutralys	Hayes (2018)	unknown		nd			0.93			97.3
	Pea		Hughes et al. (2011)	unknown		nd			0.73			nd
	Concentrate	Rutherfurd et al. (2015)	male rats		0.822			0.860			99.0
			Mathai et al. (2017)	pigs	0.45	0.62	0.73	0.49	0.71	0.75 0.84	95
	Flour	UNJURY® (2019)	unknown		nd			nd			69
			UNJURY® (2019)	unknown		nd			nd			95
	Isolate	Hughes et al. (2011)	rats		nd			0.95 to 0.98		96-44 to 97.88
	Soybean		Rutherfurd et al. (2015)	male rats	0.898 to 0.906			0.898 to 0.974		98.2 to 98.5
			Mathai et al. (2017)	pigs	0.43	0.84	0.98	0.71	0.86	0.93 1.02	94
	Concentrate	Hughes et al. (2011)	rats		nd			1.00			96.97
	Flour	Mathai et al. (2017)	pigs	0.73	0.89	1.05	0.72	0.93	0.98 1.09	92

Table 5 :

 5 Soybean and pea fatty acids[START_REF] Grela | Fatty acid composition and tocopherol content of some legume seeds[END_REF]

	Amino
		Iso Leu Lys Met Phe Thr Trp Val Arg His Ala Asp Cys Glu Gly Pro Ser Tyr
	acids
		% of amino acid/total amino acid
	Soybean 4.7 8.3 5.7 1.4 5.4 3.9 1.4 4.6 7.0 2.5 4.3 10.6 1.9 19.4 4.6 5.3 5.9 3.2
	Pea	3.7 7.4 7.7 1.2 4.7 4.0 1.1 4.4 7.7 2.8 4.8 12.0 1.7 19.0 4.8 4.2 5.4 3.5
		g of amino acid /100g protein
	Soybean 2.0 3.5 2.4 0.6 2.3 1.6 0.6 1.9 2.9 1.1 1.8 4.4 0.8 8.1 1.9 2.2 2.5 1.4
	Pea	3.3 6.6 6.8 1.0 4.2 3.6 0.9 3.9 6.8 2.5 4.3 10.7 1.6 16.9 4.3 3.4 4.8 3.1

India.

Journal of Applied and Natural Science, 7( 2),


Daniel Jaimes-Albornoz

Lionel Mannone

Stephanie Nguyen-Quoc

Yves Chalandon

Patrice Chevallier

Mohamad Mohty

Mathieu Meunier

Marie Robin

Marie-Pierre Ledoux

Gaelle Guillerm

Stéphanie Nguyen-Quoc

Gaëlle Guillerm

Jacques-Olivier Bay

Xavier Poiré

Natacha Maillard

Mathieu Leclerc

Etienne Daguindau

Yves Beguin

Marie Thérèse Rubio

MD Emmanuel Gyan
email: emmanuel.gyan@univ-tours.fr

Allogeneic Stem Cell Transplantation in Therapy-Related Myelodysplasia after Autologous Transplantation for Lymphoma: A Retrospective Study of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy

Keywords: Allogeneic transplant in secondary myelodysplasia Allogeneic stem cell transplantation, therapy-related myelodysplasia, autologous stem cell transplantation, lymphoma

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

Treatment options for lymphoid neoplasms include autologous stem-cell transplantation (ASCT). ASCT may be used for the treatment of relapsed or refractory follicular, diffuse large B-cell, Hodgkin's, or T-cell lymphoma and is associated with improved remission rates and prolonged survival. [START_REF] Appelbaum | Successful engraftment of cryopreserved autologous bone marrow in patients with malignant lymphoma[END_REF][START_REF] Linch | Dose intensification with autologous bone marrow transplantation in relapsed and resistant Hodgkin's disease: results of a BNLI randomised trial[END_REF][START_REF] Philip | Autologous bone marrow transplantation as compared with salvage chemotherapy in relapses of chemotherapy-sensitive non-Hodgkin's Lymphoma[END_REF] Adequate patient selection and advances in supportive care have improved outcomes of intensive chemotherapy in recent years. However, such prolongation of survival is also associated with late complications, such as the development of myeloid neoplasm consecutive to the treatment received, including the conditioning chemotherapy of ASCT. [START_REF] Stone | Myelodysplastic Syndrome after autologous transplantation for lymphoma: The price of progress?[END_REF][START_REF] Howe | Secondary myelodysplastic syndrome and acute myelogenous leukemia are significant complications following autologous stem cell transplantation for lymphoma[END_REF][START_REF] Gyan | High-dose therapy followed by autologous purged stem cell transplantation and doxorubicin-based chemotherapy in patients with advanced follicular lymphoma: a randomized multicenter study by the GOELAMS with final results after a median followup of 9 years[END_REF] The risk of developing therapy-related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML) secondary to the use of both alkylating agents and topoisomerase inhibitors ranges from 5 to 7% in most series, although there are studies with very variable and extreme incidences between 1% at 30 months to 11.7% at six years and may continue to increase until 12-15 years after ASCT. [START_REF] Akhtari | Therapy-related myeloid neoplasms after autologous hematopoietic stem cell transplantation in lymphoma patients[END_REF][START_REF] Pedersen-Bjergaard | Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation[END_REF] Therapy-related MDS is associated with a high incidence of cytogenetic abnormalities, with frequent deletions or monosomies of chromosomes 5 and 7. [START_REF] Pedersen-Bjergaard | Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation[END_REF][START_REF] Smith | Clinical-cytogenetic associations in 306 patients with therapy-related myelodysplasia and myeloid leukemia: the University of Chicago series[END_REF] These abnormalities have been described after the use of alkylating agents, confirming their role in the development of myelodysplasia. [START_REF] Akhtari | Therapy-related myeloid neoplasms after autologous hematopoietic stem cell transplantation in lymphoma patients[END_REF][START_REF] Pedersen-Bjergaard | Therapy-related acute myeloid leukemia and myelodysplasia after high-dose chemotherapy and autologous stem cell transplantation[END_REF] Most cytogenetic alterations and acquired mutations are associated with a poor prognosis linked to a low response to chemotherapy and short duration of remission. [START_REF] Armand | Impact of cytogenetics on outcome of de novo and therapy-related AML and MDS after allogeneic transplantation[END_REF][START_REF] Yoshizato | Genetic abnormalities in myelodysplasia and secondary acute myeloid leukemia: impact on outcome of stem cell transplantation[END_REF][START_REF] Chang | IBMTR Severity Index for grading acute graft-versus-host disease: retrospective comparison with Glucksberg grade[END_REF] Although allo-SCT has been widely studied in the context of t-AML studies focusing on t-MDS are rare. Furthermore, the best time to perform allogeneic allo-HSCT in this group of patients is unknown as well as predictors that might help patient selection are lacking. 13,14 We thus launched a retrospective multicentric study to evaluate the results of all consecutive allogeneic transplantation in population MDS secondary to autologous SCT for lymphoma

PATIENTS AND METHODS

Data collection

The registry coordinated by the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) of the European Project Manager Internet Server database (ProMISe) was used as the data source. An electronic letter of authorization for the collection and use of the data for this retrospective study was sent to each center. All patients had given written consent before transplant for data collection in ProMISe for future research, in accordance with the Declaration of Helsinki. The scientific council of the SFGM-TC approved this study on February 2, 2017.

Patient selection

For this retrospective study, we considered all consecutive adult patients who received an allogeneic transplant for the treatment of t-MDS to ASCT for lymphoid neoplasms registered from 2006 to 2016 in the ProMISe SFGM-TC database.

Patients who received an ASCT and developed secondary t-AML or those who had t-MDS which progressed to t-AML before allo-HSCT were not included. Patients who received ASCT due to neoplasms other than lymphoid neoplasms were not included.

Definitions

Lymphoid neoplasms were categorized according to the WHO 2008 classification. The types of MDS followed the WHO 2008 criteria for MDS and were adapted to the WHO 2016 classification. 15 The cytogenetic classification was assessed according to the IPSS score. 16 Lower-risk MDS comprised MDS with low-risk and intermediate-1 risk IPSS scores, and higher risk MDS those with intermediate-2 and high-risk IPSS scores. MDS-EB-1 and MDS-EB-2 were defined according to WHO and were analyzed together. The other categories of MDS with <5% blasts in bone marrow (MDS SLD, MDS MLD, MDS-RS-SLD, MDS-RS-MLD, MDS del(5q), MDS-U) were analyzed together. The response criteria in MDS in patients who received some type of treatment after or before allo-HSCT was defined according to the International Working Group response criteria 17 .

Acute GvHD was described according to the criteria of the International Bone Marrow Transplantation Registry. 17 For the analysis of CMV serostatus, the most hazardous combination, defined as a CMV-seronegative recipient and CMVseropositive donor, was compared with the other possible combinations. Intensity of the allo-HSCT conditioning regimen was analyzed according to previously established working definitions. 18 Only two categories were considered in the analysis: myeloablative and reduced-intensity conditioning, due to the multiple schemes and doses used. HLA mismatch was defined as the presence of at least one difference in the HLA-A, -B, -Cw, DR, or DQ loci. For the analysis, no mismatch HLA comprised identical-sibling donor and matched unrelated donor 10/10 (MUD), and HLA mismatched those with mismatched unrelated donor 9/10 (MMUD) and cord blood units 4/6 and 5/6.

Overall Survival (OS) was defined as the period from the day of allo-HSCT until the day of death from any cause or date of the last recorded follow-up.

Non-relapse mortality (NRM) was defined as death from any cause other than relapse of MDS, including progression to AML, from the day of allo-HSCT.

Relapse was defined as a relapse of MDS or progression to AML according to the WHO criteria.

Statistical analysis

The characteristics of the patients and the factors related to lymphoma, ASCT, t-MDS, and allo-HSCT are summarized with descriptive statistics. The primary endpoint of the study was OS, which was calculated using the Kaplan-Meier method.

The frequency of NRM and relapse was calculated by cumulative incidences.

The prognostic effects of the factors with respect to OS, NRM, and relapse were analyzed with a log-rank test (Mantel-Cox) by univariate analysis. The multivariate analysis was performed using the potential predicting factors that were significant by univariate analysis with Cox proportional hazards regression models. The calculations were performed with SPSS software version 23.0.

RESULTS

To date, the French ProMISe database includes 74,779 autologous transplant and 38,860 allogeneic transplant observations from 98 centers in France, Belgium, and Switzerland. We searched the French ProMISe database for all registered patients from January 2006 to December 2016. A total of 47 patients who met the inclusion criteria were included.

Lymphoma and ASCT

The initial neoplasm for eight patients (17.0%) was a Hodgkin Lymphoma, whereas it was a Non-Hodgkin Lymphoma for 37 (78.7%) (Table 1). Fourteen patients (29.8%) received more than two lines of chemotherapy before autologous transplantation (range 0-8). Conditioning consisted in Carmustine -Etoposide -Cytarabine -Melphalan (BEAM) for 80.8% of patients and other regimens for only 19.2%. Thirtyseven patients (78.7%) achieved complete remission. There were no patients with relapsed lymphoma at the time of allo-HSCT, but it is unknown whether there were patients who relapsed or progressed from lymphoma between ASCT and allo-HSCT. There were no patients who relapsed from lymphoma after allo-HSCT.

MDS

The median time from ASCT to the diagnosis of t-MDS was 74.4 months (range 2. Cytogenetic data were obtained for 41 patients: 82.9% had at least one cytogenetic abnormality. The most frequent cytogenetic anomalies were on chromosomes 7 (11 patients, 23.4%) and 5 (six patients, 12.8%) or both of those (fifteen patients, 31.9%).

Among the patients, 23.4% were considered to be at low risk and 59.6% at high-risk.

Sixty-eight percent of patients received at least one treatment line before allo-HSCT: 16 (34.1%) received hypomethylating agents and 11 (23.4%) AML-like induction treatment. Ten patients (21.3%) achieved complete remission before transplantation and 36 (76.6%) were not in complete remission prior to allo-HCST.

HSCT

The characteristics of the patients at allo-HSCT are shown in Table 2.

The median age at allo-HSCT was 58 years (range: 30 -71 years) and most of the patients were male (78.7%). The median time interval from diagnosis of t-MDS to allogeneic transplantation was 7.9 months (range: 2.5 -16.8).

Peripheral blood stem-cells (PBSC) were the source used for 87.4% of patients.

Nineteen patients (40.5%) were transplanted from an HLA-identical sibling donor and 17 (36.2%) from a matched unrelated donor. 10 patients (21.2%) had an mismatched unrelated donor including three patients (6.3%) received umbilical cord blood transplantation (one with a double cord). None of them received a haploidentical donor. Myeloablative conditioning (MAC) was used in nine patients (19.1%), four received a combination of busulfan/cyclophosphamide regimen (two BuCy and two CyBu), with conventional doses (12.8 mg/kg busulfan IV, 120 mg/kg cyclophosphamide), three a combination of fludarabine/busulfan with ATG (150 mg/m 2 fludarabine, 12.8 mg/kg busulfan and various doses of ATG between 2.5 mg-5 mg/kg), one fludarabine/busulfan without ATG (160 mg/m 2 fludarabine, 9.6 mg/kg busulfan), and one fludarabine and TBI (120 mg/m 2 fludarabine, 8 Gy TBI). Performance status was assessed using the Karnofsky Performance Score (KPS): 29 patients (61.8%) had a score of 90-100 before transplantation.

Response to allo-HSCT and complications.

The median duration of post-transplant follow-up was 22 months (range 0.7-107) and median survival 6.9 months (95% CI 0-19).

Thirty-four patients (72.3%) were in complete response after allo-HSCT and nine patients (19.1%) had a relapse/progression post-transplantation. The response was not evaluated for four patients (8.6%) because of the early death of three and lost to follow-up one of them.

Acute GvHD occurred in 20 patients (42.5%), seven (14.8%) had grade I, and 13 (27.7%) had a grade requiring treatment (Grade II-IV). Ten patients (21.3%) developed chronic GvHD, of whom four (8.6%) had extensive and six (12.7%) limited involvement At the time of the analysis in August 2017, there were 15 relapses or progressions of which 13 died: 12 related to relapse and one could not determine the cause. 11 patients in complete remission died due to transplant complications, mainly infectious. 3 patients had early death due to transplant complications without knowing the response obtained to the transplant. No deaths due to veno-occlusive disease or graft rejection were reported.

The causes of death are listed in Table 3.

Univariate and Multivariate analysis of patients

OS for all patients was 45% (95% confidence interval 29-60) at first year, 39% (95% CI 24-55) at 2 years and 30% (95% CI 15-45) at 3 years (Table 4 and Figure 1). Univariate analysis found that prior therapy of t-MDS with hypomethylating agents before allo-HSCT (p=0.02) and the presence of an HLA mismatch (p=0.004) were associated with poorer OS (Table 5). Multivariate analysis showed only a nonstatistically significant association with poorer OS for patients receiving a treatment based on hypomethylating agents (HR, 3.55; 95% CI, 0.97 -12.97; p=0.06), and no other clinically significant factors (Table 6).

NRM was 35% (95% CI 18-51) at first year, 39% (95% CI 21-56) at 2 years, and 44% (95% CI 25-63) at 3 years (Table 4 and Figure 1). Univariate analysis identified gender (p=0.02), graft type (p=0.02) mismatched unrelated donor type (p<0.001) and the presence of an HLA mismatch (p=0.001) to be significant risk factors (Figure 2). Multivariate analysis showed an association between the use of a mismatch unrelated donor (MMUD) and shorter survival after transplantation, relative to identical siblings or matched unrelated donors (MUD) (HR, 6.21; 95% CI, 1.63-23.62; p=0.007)

The risk of relapse was 35% (95% CI 18-53) at first year, 41% (95% CI 22-61) at 2 years and 41% (95% CI 22-61) at 3 years (Table 4 and Figure 1). The type of MDS and presence of marrow blasts (p=0.008) were the most significant predictive factor of relapse in univariate analysis, however multivariate analysis did not identify the presence of marrow blasts as a significant factor of relapse.

DISCUSSION

This retrospective study of the SFGM-TC, which examined the experience of allo-HSCT in patients, with t-MDS after an ASCT for lymphoid neoplasm, over 10 years, showed donor mismatch to adversely affect OS. This is the first series published in this specific population. In other studies, such patients account for 7 -32% of the sample. 13,14,[START_REF] Bacigalupo | Defining the Intensity of Conditioning Regimens: Working Definitions[END_REF][START_REF] Ballen | Bone marrow transplantation for therapy-related myelodysplasia: comparison with primary myelodysplasia[END_REF][START_REF] Yakoub-Agha | Allogeneic Bone Marrow Transplantation for Therapy-Related Myelodysplastic Syndrome and Acute Myeloid Leukemia: A Long-Term Study of 70 Patients-Report of the French Society of Bone Marrow Transplantation[END_REF][START_REF] Witherspoon | Hematopoietic Stem-Cell Transplantation for Treatment-Related Leukemia or Myelodysplasia[END_REF][START_REF] Yokoyama | Hematopoietic stem cell transplantation for therapy-related myelodysplastic syndrome and acute leukemia: a single-center analysis of 47 patients[END_REF][START_REF] Spina | Allogeneic stem cell transplantation in therapy-related acute myeloid leukemia and myelodysplastic syndromes: impact of patient characteristics and timing of transplant[END_REF][START_REF] Alam | Outcomes of patients with therapyrelated AML/myelodysplastic syndrome (t-AML/MDS) following hematopoietic cell transplantation[END_REF][START_REF] Finke | Long-term follow-up of therapy-related myelodysplasia and AML patients treated with allogeneic hematopoietic cell transplantation[END_REF] Most of the survival data of these studies show results for a mix of patients, including those with t-AML and t-MDS exposed to multiple treatments (chemotherapy and/or radiotherapy, and not necessarily previous ASCT) and various primary diseases (solid organ neoplasms, lymphoid neoplasms, myeloid neoplasms, and congenital anomalies).

Although allo-HSCT has been used as a curative therapeutic modality for eligible patients, data published by several groups have shown poor long-term survival. 13,14,19- 21 In our series, the median overall survival was 6.9 months with OS at first and third year of 45 and 30%, respectively. The high NRM and relapse rates at three years (44% and 41%, respectively) were similar to those previously reported by other studies, consistent with the poor prognosis of these patients.

Relapse or progression of t-MDS was the main cause of mortality (44.4%) in our study. Patients with MDS-EB-1 and MDS-EB-2 had a higher risk of relapse by univariate analysis. The association of these aggressive variants of myelodysplasia with higher relapse rates has been described in other studies on patients with various primary diseases. It is not known whether treating t-MDS before transplantation can decrease the risk of relapse or whether maintenance treatment should be started after transplant to prevent relapse. In our study, the only type of pre-transplant treatment associated with improved survival was AML-like therapy even if they had not achieved CR before transplantation, in univariate analysis (p= 0.02). The multivariate analysis shows a non-statistically significant association of hypomethylating agents before transplantation with a poorer OS (HR 3.55, 95% CI 0.97-12.97, p=0.06) regardless of the response they obtained with this treatment before transplantation, in contrast to patients with de novo MDS and poor risk cytogenetics, who normally benefit from this approach. [START_REF] Malcovati | Diagnosis and treatment of primary myelodysplastic syndromes in adults: Recommendations from the European LeukemiaNet[END_REF] Our results are not valued for the sample size and the retrospective analysis. Prospective studies are necessary to determine the benefit of a type of treatment before transplantation [START_REF] Metafuni | Allogeneic Hematopoietic Stem Cell Transplantation In Therapy-Related Myeloid Neoplasms (t-MN) of the Adult: Monocentric Observational Study and Review of the Literature[END_REF] A retrospective analysis that included more patients with t-AML than t-MDS, reports relapse rates of 42% and 44% at 5 and 10 years with OS of 38% and 24% respectively, when AML-like chemotherapy is used before transplantation. [START_REF] Alam | Outcomes of patients with therapyrelated AML/myelodysplastic syndrome (t-AML/MDS) following hematopoietic cell transplantation[END_REF] No patient in our study received post-transplant maintenance therapy. The use of maintenance therapy, with low doses of azacytidine after allo-HSCT [START_REF] Malcovati | Diagnosis and treatment of primary myelodysplastic syndromes in adults: Recommendations from the European LeukemiaNet[END_REF] and azacytidine [START_REF] Lima | Maintenance therapy with low-dose[END_REF] or decitabine with infusion of donor lymphocytes 30 , has been published recently and may be worth considering. Targeted therapies, directed against mutated oncogenes, such as IDH-1, IDH-2, or FLT-3 genomic alterations, may improve the outcome of specific subsets of patients in the future.

Infections and GVHD were the main cause of non relapse mortality.

In our series there were 27 deaths, 12 were due to relapse, 8 due to infections and 3 due to GVHD. The few deaths due to GVHD show the intensity of the immunosuppressive prophylaxis used, limiting the graft-versus-tumor effect, increasing the possibility of relapse and the appearance of infections. Multiple schemes and doses used in conditioning and immunosuppressive prophylaxis, testing the usual drugs, have not allowed to identify whether one scheme is superior to another. A significant factor to improve survival was the absence of a mismatch by using either HLA identical-sibling or matched unrelated donors, as previously reported. 14 A prospective study of the SFGM-TC reported better OS (37% vs 15%, p=0.02) of patients with high-risk MDS who had identical HLA donors versus those who did not. 31 In our series, there was a lower frequency of NRM in patients with 10/10 donors than 9/10 donors (HR, 6.21, 95% CI, 1.63-23.62, p=0.007), although was not significative in OS by multivariate analysis. NRM associated with mismatched HLA donors could be improved with new prophylactic strategies to counter GvHD, such as post-transplant cyclophosphamide (PT-Cy). Reports over the last years on a small number of patients with de novo MDS/AML and t-MN who underwent allo-HSCT show similar results for HLA identical-sibling, MUD, or haploidentical donors. 32 A recent retrospective series of EBMT in patients with MDS who underwent haploidentical transplants reported better OS for patients treated with PT-Cy than those who were not (OS at three years of 38% vs 28%), but with high NRM (41% vs 55%). 33 This modality may be an acceptable option, although the risk of relapse remains high and variations in the dose of PT-Cy have even been tested in high-risk patients with refractory MDS/AML. 34 Indeed, older patients were recently reported to have OS of 42%, and a relapse rate of 24% at two years. 35 Strategies to improve progression-free survival and decrease NRM using PT-Cy have been implemented. The ALTERGREF trial (NCT03250546), currently in the inclusion phase, will evaluate the effect of PT-Cy for prevention of GvHD in haploidentical and HLA-9/10 mismatched unrelated donors transplant.

The proportion of patients with high risk cytogenetic has been previously reported to be 17 -49%. 13,14,[START_REF] Yokoyama | Hematopoietic stem cell transplantation for therapy-related myelodysplastic syndrome and acute leukemia: a single-center analysis of 47 patients[END_REF][START_REF] Spina | Allogeneic stem cell transplantation in therapy-related acute myeloid leukemia and myelodysplastic syndromes: impact of patient characteristics and timing of transplant[END_REF] In our study, 68% (32 patients) had adverse cytogenetic alterations, especially abnormalities in chromosomes 5 and 7. However, the results were probably not significant for the few patients in the other risk categories.

The best time to perform the transplant is unknown. It is possible that rapid transplantation could reduce the risk of t-MDS/t-AML-related deterioration. [START_REF] Alam | Outcomes of patients with therapyrelated AML/myelodysplastic syndrome (t-AML/MDS) following hematopoietic cell transplantation[END_REF] Although a higher frequency of NRM is possible if the transplant is performed beyond six months (50% vs 12.5%, p=0.03) caused by toxicity and infections due to multiple chemotherapy cycles [START_REF] Yokoyama | Hematopoietic stem cell transplantation for therapy-related myelodysplastic syndrome and acute leukemia: a single-center analysis of 47 patients[END_REF] , we found no difference in OS or NRM. Although the median age of 58 years is higher than for other large related series and 60% of patients had a KPS ≥ 90, these factors did not play a significant role in survival, as in other series. [START_REF] Chang | IBMTR Severity Index for grading acute graft-versus-host disease: retrospective comparison with Glucksberg grade[END_REF][13][14][START_REF] Ballen | Bone marrow transplantation for therapy-related myelodysplasia: comparison with primary myelodysplasia[END_REF][START_REF] Yokoyama | Hematopoietic stem cell transplantation for therapy-related myelodysplastic syndrome and acute leukemia: a single-center analysis of 47 patients[END_REF][START_REF] Alam | Outcomes of patients with therapyrelated AML/myelodysplastic syndrome (t-AML/MDS) following hematopoietic cell transplantation[END_REF] Our data also do not support that factors related to the primary disease and its treatment can influence survival. Interestingly, no veno-occlusive disease was observed in this population having received a previous autologous transplantation.

A retrospective report of EBMT found better results in the period between 1998 and 2006 than for transplants performed before 1998 (40% vs 29%, p=0.02). 13 We found no differences between the periods of 2006-2010 and 2011-2016, probably because support care has not changed as much in the last 10 years as during the transition from the 80's to 90's.

Treatment options are still limited for patients who are not candidates for allo-HSCT.

Other therapeutic strategies have been tested using azacitidine or clofarabine associated with chemotherapy with encouraging results. 36,37 The limitations of our study include the collection of retrospective data and the absence of a historical group for comparisons. Patient selection may have varied between centers. The small number of patients and the low incidence of secondary myelodysplasia makes it difficult to perform a prospective study.

In summary, although the number of patients in this study was small, the results suggest that patients receiving an ASCT for a lymphoid neoplasm who develop t-

  2-259). Eleven patients (23.5%) had MDS-EB-1, 12 (25.6%) MDS-EB-2, and 22 (46.7%) other types of MDS. No diagnostic information was obtained for two patients (4.2%).

  Thirty-eight patients (80.9%) received reduced intensity conditioning (RIC). 22 patients received a combination of fludarabine-busulfan-based RIC with ATG or ALG (100-150 mg/m 2 fludarabine, 3.2-6.4 mg/kg busulfan, 2.5-5 mg/kg ATG or 5-20 mg/kg ALG). 4 patients received fludarabine-busulfan-based RIC without ATG. Eight patients received fludarabine-TBI-based RIC (2Gy-8 Gy) and four patients received sequential FLAMSA-RIC. Eighteen patients (38.3%) received prophylaxis with cyclosporine (CsA) and mycophenolate mofetil (MMF) and 11 (23.4%) cyclosporine and methotrexate (MTX). Twelve patients (25.5%) received only cyclosporine and six (12.8%) received other regimens. The most frequent serological status for cytomegalovirus (CMV) was 29.7% R + /D + . Thirteen transplants (27.1%) were performed with the combination R + /D -.

  MDS have short OS after allo-HSCT, with few long-time survivors. The use of MMUD donors with standard GvHD prophylaxis should be avoided in such indications for allo-HSCT. Studies that attempt to determine whether the implementation of Cy post transplantation would improve these outcomes with mismatched donors are still ongoing. It remains necessary to explore more alternatives and transplant strategies in this critical population. patients with myelodysplastic syndrome or acute myeloid leukemia arising from myelodysplastic syndrome: similar outcomes in patients with de novo disease and disease following prior therapy or antecedent hematologic disorders. Blood. 2007; 110: 1379-1387. 13. Kröger N, Brand R, Van Biezen A, et al. Risk factors for therapy-related myelodysplastic syndrome and acute myeloid leukemia treated with allogeneic stem cell transplantation. Haematologica. 2009; 94: 542-549. 14. Litzow MR, Tarima S, Pérez WS, et al. Allogeneic transplantation for therapyrelated myelodysplastic syndrome and acute myeloid leukemia. Blood. 2010; 115: 1850-1857. 15. Arber DA, Orazi A, Hasserjian R, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016; 127: 2391-2405. 16. Greenberg P, Cox C, Le Beau MM, et al. International scoring system for evaluating prognosis in Myelodysplastic Syndromes. Blood. 1997; 89: 2079-2088. 17. Cheson B, Greenberg P, Bennett J, et al. Clinical application and proposal for modification of the International Working Group (IWG) response criteria in myelodysplasia. Blood. 2006; 108: 419-425 azacitidine after allogeneic hematopoietic stem cell transplantation for relapsed AML or MDS: a dose and schedule finding study. Cancer. 2010; 116: 5420-5431. 30. Steinmann J, Bertz H, Wäsch R, et al. 5-Azacytidine and DLI can induce longterm remissions in AML patients relapsed after allograft. Bone Marrow Transplant. 2015; 50: 690-695. 31. Schroeder T, Rautenberg C, Krüger W, et al. Treatment of relapsed AML and MDS after allogeneic stem cell transplantation with decitabine and DLI-a retrospective multicenter analysis on behalf of the German Cooperative Transplant Study Group. Ann Hematol. 2018; 97: 335-342. 32. Robin M, Porcher R, Adès L, et al. HLA-matched allogeneic stem cell transplantation improves outcome of higher risk myelodysplastic syndrome A prospective study on behalf of SFGM-TC and GFM. Leukemia. 2015; 29: 1496 -1501. 33. Di Stasi A, Milton DR, Poon LM, et al. Similar transplantation outcomes for acute myeloid Leukemia and myelodysplastic syndrome patients with haploidentical versus 10/10 human leukocyte antigen-matched unrelated and related donors. Biol Blood Marrow Transplant. 2014; 20:1975 -1981. 34. Robin M, Porcher R, Ciceri F, et al. Haploidentical transplant in patients with myelodysplastic syndrome. Blood. advances 2017; 1:1876 -1883. 35. Nakamae H, Koh H, Katayama T, et al. HLA haploidentical peripheral blood stem cell transplantation using reduced dose of posttransplantation cyclophosphamide for poor-prognosis or refractory leukemia and myelodysplastic syndrome. Exp Hematol. 2015; 43: 921-929. 36. Ciurea SO, Shah MV, Saliba RM, et al. Haploidentical transplantation for older patients with acute myeloid leukemia and myelodysplastic syndrome. Biol Blood Marrow Transplant. 2018; 24:1232-1236. 37. Ballya C, Thépota S, Quesnela B, et al. Azacitidine in the treatment of therapy related myelodysplastic syndrome and acute myeloid leukemia (tMDS/AML): A report on 54 patients by the Groupe Francophone des Myelodysplasies (GFM). Leuk Res. 2013; 37: 637-640. 38. Jabbour E, Faderl S, Sasaki K, et al. Phase 2 Study of Low-Dose Clofarabine Plus Cytarabine for patients with higher risk Myelodysplastic Syndrome who have relapsed or are refractory to hypomethylating agents. Cancer. 2016; 1-9.

Table 1 . Patient characteristics at autologous stem cell transplantation

 1

	Patient characteristics	Overall population, n (%)
	Number of patients	47 (100)
	Gender
	Male	37 (78.7)
	Female	10 (21.3)
	Lymphoid Hematological malignancy
	Follicular lymphoma	12 (25.6)
	Diffuse Large B-cell lymphoma	12 (25.6)
	Hodgkin lymphoma	8 (17.0)
	Mantle cell lymphoma	5 (10.6)
	Burkitt lymphoma	2 (
	Nodal marginal zone lymphoma
	Small lymphocytic lymphoma
	Lymphoplasmacytic lymphoma
	Waldenstrom macroglobulinemia
	Peripheral T-cell lymphoma
	Angioimmunoblastic T-cell lymphoma
	Unknown

Table 2 . Patient characteristics at allogeneic hematopoietic stem cell transplantation

 2

	Previous lines of therapy
	1	9 (19.1)
	2	24 (51.1)
	≥ 3	10 (21.3)
	Unknown	4 (8.5)
	Conditioning ASCT
	BEAM	38 (80.8)
	Chemotherapy + TBI	7 (14.9)
	Unknown	2 (4.3)
	Response to ASCT
	Complete remission	37 (78.7)
	Not in Complete remission	4 (8.5)
	Unknown	6 (12.8)
	ASCT, autologous stem cell transplantation; BEAM, carmustine -etoposide -
	cytarabine -melphalan; TBI, total body irradiation.

Table 3 . Causes of death according to the response at allo-HSCT.

 3

	Cause of death	CR	Not in CR	Unknown
	Relapse/Progression	12 (44.4%)	4	8
	NRM causes	14 (51.9%)	11		3
	Sepsis / MODS	8
	GvHD	3
	Pulmonary toxicity	1
	Hemorrhage	2
	Graft rejection	0
	VOD	0
	Unknown	1 (3.7%)	1
	Total deaths	27 (100 %)	16 (59.3%)	8 (29.6.%)	3 (11.1%)
	HSCT, hematopoietic stem cell transplantation; NRM, non-relapse mortality; MODS,
	multiple organ dysfunction syndrome; GvHD, graft versus host disease; VOD, veno-
	occlusive disease

Table 4 . Outcome of patients treated with allo-HSCT for t-MDS to ASCT for lymphoid neoplasms.

 4

		Non-relapse	Relapse	Overall survival
		mortality
	At 1 year	35% (18 -51)	35% (18 -53)	45% (29 -60)
	At 2 years	39% (21-56)	41% (22 -61)	39% (24 -55)
	At 3 years	44% (25 -63)	41% (22 -61)	30% (15-45)
	HSCT, hematopoietic stem cell transplantation; t-MDS, therapy-related
	myelodysplastic syndrome; ASCT, autologous stem cell transplantation. All values
	are represented as % (95% confidence interval, CI).

Table 5 . Univariate analysis for probabilities of outcomes of non-relapse mortality, relapse, and overall survival at 3 years after HSCT.

 5 -relapse mortality; R, relapse; OS, overall survival; HSCT, hematopoietic stem cell transplantation; NHL, non-hodgkin lymphoma; HL, hodgkin lymphoma; ASCT, autologous stem cell transplantation; BEAM, carmustine -etoposide -cytarabine -melphalan; TBI, total body irradiation; MDS, myelodysplastic syndrome; MDS-EB-1, myelodysplastic syndrome with excess blasts-1; MDS-EB-2, myelodysplastic syndrome with excess blasts-2; IPSS, international prognostic scoring system; AML, acute myeloid leukemia; MAC, myeloablative conditioning; RIC, reduced intensity conditioning; PBSC, peripheral blood stem cell; BM, bone marrow; CB, cord blood; GvHD, graft versus host disease; CsA, cyclosporine; MTX, methotrexate; MMF, mycophenolate mofetil; HLA, human leukocyte antigen; CMV, cytomegalovirus; R: receptor; D, donor; KPS, karnofsky performance status.

	Non-relapse Mortality	Relapse	Overall survival
	(NRM)	(R)	(OS)

Table 6 . Multivariate analysis of outcomes of non-relapse mortality, relapse, and overall survival after HSCT.

 6 NRM, non-relapse mortality; R, relapse; OS, overall survival; MDS, myelodysplastic syndrome; HSCT, hematopoietic stem cell transplantation; AML, acute myeloid leukemia; HLA, human leukocyte antigen; MDS-EB-1, myelodysplastic syndrome with excess blasts-1; MDS-EB-2, myelodysplastic syndrome with excess blasts-2.

		Overall survival		Non-relapse mortality	Relapse
		(OS)		(NRM)		(R)
		HR (95% CI)	p-value	HR (95% CI)	p-value	HR (95% CI)	p-value
	Prior therapy for MDS
	before HSCT
	AML-like induction	1.0	0.13
	Hypomethylating agents	3.55 (0.97 -12.97)	0.06
	No chemotherapy	1.79 (0.52 -6.15)	0.35
	HLA Mismatch		0.13		0.007
	No (10/10)	1.0	1.0
	Yes (9/10, 4/6, 5/6)	2.04 (0.80 -5.22)	6.21 (1.63 -23.62)
	MDS Diagnosis						0.21
	Other MDS				1.0
	MDS EB-1/EB-2				2.63 (0.57 -12.03)

ACKNOWLEDGEMENTS

The authors thank Nicole Raus and Réda Chebel from the SFGM-TC for data collection and management, and all the data managers of the participating centers for providing supplementary data.

AUTHOR CONTRIBUTIONS

EG and DJA designed the study, analyzed the data, and wrote the paper. All authors provided patient data, approved the study design, critically reviewed the manuscript and approved the final draft.

CONFLICT OF INTEREST

The authors declare no conflict of interest.