KIR in Allogeneic Hematopoietic Stem Cell Transplantation: Need for a Unified Paradigm for Donor Selection

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a lifesaving therapy for hematological malignancies. For years, a fully matched HLA donor was a requisite for the procedure. However, new immunosuppressive strategies have enabled the recruitment of viable alternative donors, particularly haploidentical donors. Over 95% of patients have at least two potential haploidentical donors available to them. To identify the best haploidentical donor, the assessment of new immunogenetic criteria could help. To this end, the clinical benefit of KIR genotyping in aHSCT has been widely studied but remains contentious. This review aims to evaluate the importance of KIR-driven NK cell alloreactivity in the context of aHSCT and explain potential reasons for the discrepancies in the literature. Here, through a non-systematic review, we highlight how the studies in this field and their respective predictive models or scoring strategies could be conceptually opposed, explaining why the role of NK cells remains unclear in aHCST outcomes. We evaluate the limitations of each published prediction model and describe how every scoring strategy to date only partly delivers the requirements for optimally effective NK cells in aHSCT. Finally, we propose approaches toward finding the optimal use of KIR genotyping in aHSCT for a unified criterion for donor selection

Le CMH du macaque crabier : son polymorphisme et son influence sur divers paramètres biologiques

Le macaque crabier (Macaca fascicularis) est utilisé comme modèle en immunologie expérimentale dans la mise au point de nouveaux traitements tels que la prévention du rejet d'organes transplantés, ou le traitement préventif ou curateur de maladies infectieuses. Comme chez tous les vertébrés dotés d'un système immunitaire adaptatif, le Complexe Majeur d'Histocompatibilité (CMH) du macaque crabier occupe une place privilégiée dans le développement des réponses immunitaires adaptatives de type cellulaire et humorale. L'objectif de nos travaux était d'étudier l'influence du polymorphisme du CMH sur divers traits quantitatifs biologiques reflétant le fonctionnement du système immunitaire. L'aire de répartition du macaque crabier est très grande dans le Sud-est asiatique et des animaux de différentes origines géographiques sont disponibles. Les animaux de l'île Maurice et des Philippines qui présentent un polymorphisme génétique plus restreint que ceux d'Indonésie ou du Vietnam ont la faveur de la plupart des groupes de recherche. Grâce à des techniques de biologie moléculaire éprouvés, nous avons tout d'abord décrit le polymorphisme des gènes DRA et DRB de quatre populations de macaques (Maurice, Philippines, Vietnam et Java). Quant aux gènes de classe I du CMH, leur grand nombre chez le macaque (jusqu'à 12 par génome haploïde) nous a fait opter pour le séquençage massif (pyroséquençage 454) des transcrits des gènes de classe I du CMH. Par cette technique, nous avons pu caractériser le polymorphisme des gènes de classe I exprimés chez un macaque Malaisien et de nombreux animaux d'origines Mauricienne. Le génotypage de microsatellites de la région du CMH ainsi que le génotypage du locus DRB, nous a permis de mettre en évidence l'influence du polymorphisme de la région DR sur la numération des lymphocytes T CD4+ circulant chez les macaques Philippins. Par ailleurs l'étude systématique de l'influence du polymorphisme du CMH sur les divers traits quantitatifs de la numération formule sanguine, a révélé chez ces mêmes macaques, une association entre la numération plaquettaire et la région de classe III du CMH. Dans une autre étude portant sur 45 macaques crabiers d'origine Mauricienne inoculés par SIVmac251, nous avons révélé que la charge virale plasmatique cent jours après inoculation est influencée par le polymorphisme de la région de classe IB du CMH. Le génotypage d'un grand nombre de macaques Mauriciens (N=750) par l'étude de 18 microsatellites répartis le long du CMH, nous a permis d'estimer par une méthode originale le taux de recombinaison dans le CMH dans la population de l'île Maurice qui est caractérisée par une fondation récente et une phase d'expansion rapide. Le taux de recombinaison dans cette population de macaque est 2 à 10 fois moins élevé que celui décrit pour la région HLA chez l'homme. Enfin, l'étude dans les 4 populations (Maurice, Philippines, Java et Vietnam) de microsatellites localisés dans le CMH et en dehors de ce dernier, nous a permis de détecter un signal de sélection positive dans la région de classe III. Il apparait que le signal de sélection concernerait la population de macaques crabier des Philippines et pourrait être en rapport avec la pression de sélection exercée par le Plasmodium ou d'autres agents infectieux. Au total, ces travaux nous ont permis d'augmenter nos connaissances sur le polymorphisme du CMH chez le macaque crabier et pour la première fois de mettre en évidence son influence sur des paramètres biologiques. Ces travaux devraient permettre à la communauté scientifique de mieux appréhender le macaque crabier en tant que modèle d'étude.The cynomolgus macaque (Macaca fascicularis) is used as an experimental immunology model in the development of new treatments such as the prevention of rejection of transplanted organs, or the preventive or curator treatment of infectious diseases. As in all vertebrates, the Major Histocompatibility Complex (MHC) of the cynomolgus macaque occupies a privileged place in the development of immune adaptive responses of cellular and humoral types. The aim of our work was to study the influence of MHC polymorphism on various quantitative traits reflecting the biological immune system. The distribution of cynomolgus macaque is very large in the South-East Asia and animals of different geographical origins are available. Animals of Mauritius and the Philippines, that have a genetic polymorphism smaller than those of Indonesia and Vietnam, have the favor of most research groups. By proven molecular biology techniques, we described the polymorphism of the DRA and DRB genes in four cynomolgus macaque populations (Mauritius, Philippines, Vietnam and Java). As for the MHC class I genes, their high numbers in macaques (up to 12 per haploid genome) led us to choose the massive sequencing (pyrosequencing 454) as molecular biology technique to describe the transcripts of MHC class I genes. Thus, we characterized the polymorphism of MHC class I genes expressed in a Malaysian macaque and many Mauritian animals. Genotyping of microsatellites across the MHC region and the DRB genotyping allowed us to highlight the influence of the DR polymorphisms on blood counts of CD4+ T lymphocytes in macaques from the Philippines. Moreover, the systematic study of the influence of MHC polymorphism on major blood cells, revealed in these macaques an association between platelet count and the MHC class III region. In another study of 45 Mauritian cynomolgus macaques inoculated with SIVmac251, we found that the plasma viral load measured one hundred days after inoculation is influenced by the MHC Class IB polymorphism. Genotyping of a large number of Mauritian macaques (N = 750) by studying 18 microsatellites across the MHC has allowed us to estimate, by means of an original method, the rate of recombination within the MHC in this population of Mauritius Island which is characterized by a foundation and a recent phase of rapid expansion. The recombination rate in this population is 2-10 times lower than that described for the HLA region in humans. Finally, by the study in four populations (Mauritius, Philippines, Vietnam and Java) of microsatellite located in the MHC and outside of it, we were able to detect a positive signal of selection in the MHC class III region. It appears that the selection signal could be concern the cynomolgus macaque from the Philippines and could be related to the selection pressure exerted by the Plasmodium or other infectious agents. Overall, this work allowed us to increase our knowledge of MHC polymorphism in cynomolgus macaques and for the first time to demonstrate its influence on biological parameters. This work should lead to the scientific community to better understand the cynomolgus macaque as an experimental model

Use of Cumulative Poisson Probability Distribution as an Estimator of the Recombination Rate in an Expanding Population: Example of the Macaca fascicularis Major Histocompatibility Complex

International audienceWe describe a method to estimate the rate of recombination per generation from the genotypes of a large individual sample of an expanding population, for which the founding event is dated. The approach is illustrated with an application to estimating the major histocompatibility complex (MHC) recombination rate in the Mauritian macaque population. We genotyped 750 macaques by means of 17 microsatellites across the MHC region and reconstructed the seven most frequent haplotypes assumed to represent the founding haplotypes (H rec(0)) as well as the 31% recombinant haplotypes (H rec(h)) resulting from a variable number " h " of recombinations between the founding haplotypes. The relative frequencies of the various classes of haplotypes (H rec(0) and H rec(h)) follow a Poisson distribution. By using a maximum likelihood method, we calculated the mean of the Poisson distribution that best fits the data. By dividing this mean by the number of generations (502100) from the date of the population founding, we deduced that rate of recombination in the MHC is approximately 0.004 to 0.008 in the Mauritian macaque population. When the founding date of the population is precisely known, our method presents a useful alternative to the co-alescent method

Deleterious impact of feto-maternal MHC compatibility on the success of pregnancy in a macaque model

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Comparison of NK alloreactivity prediction models based on KIR-MHC interactions in haematopoietic stem cell transplantation.

Peer reviewed: TrueThe biological processes underlying NK cell alloreactivity in haematopoietic stem cell transplantation (HSCT) remain unclear. Many different models to predict NK alloreactivity through KIR and MHC genotyping exist, raising ambiguities in its utility and application for clinicians. We assessed 27 predictive models, broadly divided into six categories of alloreactivity prediction: ligand-ligand, receptor-ligand, educational, KIR haplotype-based, KIR matching and KIR allelic polymorphism. The models were applied to 78 NGS-typed donor/recipient pairs undergoing allogeneic HSCT in genoidentical (n=43) or haploidentical (n=35) matchings. Correlations between different predictive models differed widely, suggesting that the choice of the model in predicting NK alloreactivity matters. For example, two broadly used models, educational and receptor-ligand, led to opposing predictions especially in the genoidentical cohort. Correlations also depended on the matching fashion, suggesting that this parameter should also be taken into account in the choice of the scoring strategy. The number of centromeric B-motifs was the only model strongly correlated with the incidence of acute graft-versus-host disease in our set of patients in both the genoidentical and the haploidentical cohorts, suggesting that KIR-based alloreactivity, not MHC mismatches, are responsible for it. To our best knowledge, this paper is the first to experimentally compare NK alloreactivity prediction models within a cohort of genoidentical and haploidentical donor-recipient pairs. This study helps to resolve current discrepancies in KIR-based alloreactivity predictions and highlights the need for deeper consideration of the models used in clinical studies as well as in medical practice

Whole genome sequencing in the search for genes associated with the control of SIV infection in the Mauritian macaque model

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Prognostic value for long-term graft survival of estimated glomerular filtration rate and proteinuria quantified at 3 months after kidney transplantation

International audienceBackground. The estimated glomerular filtration rate (eGFR) measured at 1 year is the usual benchmark applied in kidneytransplantation (KT). However, acting on earlier eGFR values could help in managing KT during the first post-operative year.We aimed to assess the prognostic value for long-termgraft survival of the early (3 months) quantification of eGFR andproteinuria following KT.Methods. The 3-, 6- and 12-month eGFR using the Modified Diet in Renal Disease equation (eGFRMDRD) was determined andproteinuria was measured in 754 patients who underwent their first KT between 2000 and 2010 (with a mean follow-up of8.3 years) in our centre. Adjusted associations with graft survival were estimated using a multivariable Cox model. Thepredictive accuracy was estimated using the C-index and net reclassification index. These same analyses were measured ina multicentre validation cohort of 1936 patients.Results. Both 3-month eGFRMDRD and proteinuria were independent predictors of return to dialysis (all P<0.05) and therewas a strong correlation between eGFR at 3 and 12 months (Spearman’s q¼0.76). The predictive accuracy of the 3-mont

Cynomolgus macaque IL37 polymorphism and control of SIV infection

International audienceThe association between gene polymorphisms and plasma virus load at the set point (SP-PVL) was investigated in Mauritian macaques inoculated with SIV. Among 44 macaques inoculated with 50 AID50, six individuals were selected: three with SP-PVL among the highest and three with SP-PVL among the lowest. The exons of 390 candidate genes of these six animals were sequenced. Twelve non-synonymous single nucleotide polymorphisms (NS-SNPs) lying in nine genes potentially associated with PVL were genotyped in 23 animals. Three NS-SNPs with probabilities of association with PVL less than 0.05 were genotyped in a total of 44 animals. One NS-SNP lying in exon 1 of the IL37 gene displayed a significant association (p = 3.33 × 10-4) and a strong odds ratio (19.52). Multiple linear regression modeling revealed three significant predictors of SP-PVL, including the IL37 exon 1 NS-SNP (p = 0.0004) and the MHC Class IB haplotypes M2 (p = 0.0007) and M6 (p = 0.0013). These three factors in conjunction explained 48% of the PVL variance (p = 4.8 × 10-6). The potential role of IL37 in the control of SIV infection is discussed

Whole genome sequencing in the search for genes associated with the control of SIV infection in the Mauritian macaque model

In the Mauritian macaque experimentally inoculated with SIV, gene polymorphisms potentially associated with the plasma virus load at a set point, approximately 100 days post inoculation, were investigated. Among the 42 animals inoculated with 50 AID50 of the same strain of SIV, none of which received any preventive or curative treatment, nine individuals were selected: three with a plasma virus load (PVL) among the lowest, three with intermediate PVL values and three among the highest PVL values. The complete genomes of these nine animals were then analyzed. Initially, attention was focused on variants with a potential functional impact on protein encoding genes (non-synonymous SNPs (NS-SNPs) and splicing variants). Thus, 424 NS-SNPs possibly associated with PVL were detected. The 424 candidates SNPs were genotyped in these 42 SIV experimentally infected animals (including the nine animals subjected to whole genome sequencing). The genes containing variants most probably associated with PVL at a set time point are analyzed herein.This work was supported by the “Investissements d’Avenir” programs managed by the ANR under reference ANR-11-INBS-0008 funding the Infectious Disease Models and Innovative Therapies (IDMIT, Fontenay-aux-Roses, France) infrastructure, and ANR-10-EQPX-02-01 funding the FlowCyTech facility (IDMIT, Fontenay-aux-Roses, France). We warmly thank all members of ASW and L2I core lab facility from IDMIT center. TMB is supported by MINECO BFU2014-55090-P (FEDER), U01 MH106874 grant, Howard Hughes International Early Career, Obra Social “La Caixa” and Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya