GvHD risk assessment in hematopoietic stem cell transplantation: role of cytokine gene polymorphisms and an in vitro human skin explant model

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Association of recipient and donor interleukin 6 polymorphisms 174 and 597 with outcome after allogeneic hematopoietic stem cell transplantation in children

Purpose

The success of allogeneic hematopoietic stem cell transplantation (HSCT) is compromised by complications such as infection, relapse, and graft-versus-host disease (GVHD). The investigation of non-HLA immunogenetics, particularly of cytokines, could identify predictors of an unfavorable outcome after allogeneic HSCT. In this study, we examined the impact of single nucleotide polymorphisms (SNPs) within the promoter region of interleukin 6 (IL6) on the development of GVHD after pediatric allogeneic HSCT.

Methods

In this retrospective analysis, we included 320 pediatric patients with a median age of 10 years who underwent an allogeneic HSCT and their respective donors. We used TaqMan real-time polymerase chain reaction to analyze the SNPs IL6-174 (G/C) and IL6-597 (G/A). The IL6-174 polymorphism was examined in 300 recipients and 295 donors. The IL6-597 polymorphism was analyzed in 299 recipients and 296 donors. We investigated the influence of the IL6-174 and IL6-597 polymorphisms on overall survival, event-free survival, relapse incidence, transplant-related mortality, and the occurrence of GVHD.

Results

G polymorphism at position 174 of the recipient IL6 gene was associated with a higher incidence of acute GVHD (GG vs. GC/CC; P = 0.024). Patients with IL6-597 GG genotype developed acute GVHD more frequently than individuals with an A allele (GG vs. GA vs. AA; P = 0.013). IL6-174 GG homozygous recipients had a more frequent occurrence of chronic GVHD (GG vs. GC/CC; P = 0.049). We observed a significant increased risk of chronic GVHD in recipients with IL6-597 GG genotype (GG vs. GA vs. AA; P = 0.043). Polymorphisms of donors did not affect the incidence of acute GVHD and chronic GVHD. In multivariate analysis, the IL6-174 and IL6-597 SNPs were independent significant risk factors for acute GVHD (P = 0.030; P = 0.007, respectively) as well as for chronic GVHD (P = 0.045; P = 0.015, respectively). In addition, older age at time of transplantation turned out to be a significant risk factor for chronic GVHD (P = 0.003).

Conclusion

Our study identified the IL6-174 and IL6-597 GG genotypes of pediatric allogeneic HSCT recipients as genetic risk factors for the development of acute GVHD and chronic GVHD. After evaluations in further studies, these findings could implicate the adjustment of prophylactic measures to reduce the occurrence of acute GVHD and chronic GVHD.

Immune reconstitution and graft-versus-host reactions in rat models of allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) extends the lives of thousands of patients who would otherwise succumb to hematopoietic malignancies such as leukemias and lymphomas, aplastic anemia, and disorders of the immune system. In alloHCT, different immune cell types mediate beneficial graft-versus-tumor (GvT) effects, regulate detrimental graft-versus-host disease (GvHD), and are required for protection against infections. Today, the “good” (GvT effector cells and memory cells conferring protection) cannot be easily separated from the “bad” (GvHD-causing cells), and alloHCT remains a hazardous medical modality. The transplantation of hematopoietic stem cells into an immunosuppressed patient creates a delicate environment for the reconstitution of donor blood and immune cells in co-existence with host cells. Immunological reconstitution determines to a large extent the immune status of the allo-transplanted host against infections and the recurrence of cancer, and is critical for long-term protection and survival after clinical alloHCT. Animal models continue to be extremely valuable experimental tools that widen our understanding of, for example, the dynamics of post-transplant hematopoiesis and the complexity of immune reconstitution with multiple ways of interaction between host and donor cells. In this review, we discuss the rat as an experimental model of HCT between allogeneic individuals. We summarize our findings on lymphocyte reconstitution in transplanted rats and illustrate the disease pathology of this particular model. We also introduce the rat skin explant assay, a feasible alternative to in vivo transplantation studies. The skin explant assay can be used to elucidate the biology of graft-versus-host reactions, which are known to have a major impact on immune reconstitution, and to perform genome-wide gene expression studies using controlled combinations of minor and major histocompatibility between the donor and the recipient.

Expression profiling of major histocompatibility and natural killer complex genes reveals candidates for controlling risk of graft versus host disease

Background

The major histocompatibility complex (MHC) is the most important genomic region that contributes to the risk of graft versus host disease (GVHD) after haematopoietic stem cell transplantation. Matching of MHC class I and II genes is essential for the success of transplantation. However, the MHC contains additional genes that also contribute to the risk of developing acute GVHD. It is difficult to identify these genes by genetic association studies alone due to linkage disequilibrium in this region. Therefore, we aimed to identify MHC genes and other genes involved in the pathophysiology of GVHD by mRNA expression profiling.

Methodology/Principal Findings

To reduce the complexity of the task, we used genetically well-defined rat inbred strains and a rat skin explant assay, an in-vitro-model of the graft versus host reaction (GVHR), to analyze the expression of MHC, natural killer complex (NKC), and other genes in cutaneous GVHR. We observed a statistically significant and strong up or down regulation of 11 MHC, 6 NKC, and 168 genes encoded in other genomic regions, i.e. 4.9%, 14.0%, and 2.6% of the tested genes respectively. The regulation of 7 selected MHC and 3 NKC genes was confirmed by quantitative real-time PCR and in independent skin explant assays. In addition, similar regulations of most of the selected genes were observed in GVHD-affected skin lesions of transplanted rats and in human skin explant assays.

Conclusions/Significance

We identified rat and human MHC and NKC genes that are regulated during GVHR in skin explant assays and could therefore serve as biomarkers for GVHD. Several of the respective human genes, including HLA-DMB, C2, AIF1, SPR1, UBD, and OLR1, are polymorphic. These candidates may therefore contribute to the genetic risk of GVHD in patients.

Effector CD4+ T cells, the cytokines they generate, and GVHD: something old and something new

GVHD is a syndrome that results from minor and major histocompatibility complex incompatibilities between the donor and recipient. More than 50 years after its initial description, the pathophysiology of GVHD remains poorly understood. Nonetheless, donor T cells have been shown to be critical to the pathophysiology of acute and chronic GVHD, yet precisely how they function remains unclear. The effector mechanisms by which donor T cells mediate tissue inflammation is even less well understood. Identification of several new lineages of CD4(+) T cells made in the past decade and their roles in the pathophysiology of T cell-mediated diseases has shed new light on these effector mechanisms. In this review, we summarize the recent descriptions of these T-cell lineages and the current data supporting their role in acute and to a lesser extent chronic GVHD. Investigations into the activity of these new T-cell lineages may provide more rationale approaches to the treatment or prevention of GVHD.

Interleukin-1 polymorphisms and graft-vs-host disease

Graft-vs-host disease (GVHD) remains a key limiting factor in the success of hematopoietic stem cell transplantation (HSCT). One of the key cytokines known to have a role in the pathogenesis of GVHD is interleukin-1 (IL-1). The IL-1 gene family consists of 10 members, of which 3 genes encode for the proteins IL-1a, IL-1ss and IL-1Ra (IL-1 receptor antagonist). Polymorphisms in these genes have been associated with variability in the production of the respective cytokines and have been implicated in patient susceptibility to inflammatory diseases, including GVHD. A number of reports have detailed genetic associations between members of the IL-1 gene family and HSCT outcomes. Despite these encouraging reports, a simple exploitation of these findings is probably naive. Differences in transplant practice between centers and within centers over time mean that directly comparable studies are rare. This combined with the complexity of IL-1-related transplant biology means that our understanding of this topic remains limited. This review details the current state of knowledge of IL-1 genetics and transplantation and discusses these issues in the context of the changing practice of transplantation.

IL2 and TNFA gene polymorphisms and the risk of graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

This study aimed to analyse the association of gene polymorphisms with the outcome of allogeneic haematopoietic stem cell transplantation. We studied 122 donor/recipient pairs who received HLA-identical transplants from siblings at the Universidade Estadual de Campinas, Brazil, between June 1996 and June 2006. Donor/recipient alleles for TNFA-238 and IL2-330/+166 single-nucleotide polymorphisms (SNP) were analysed by PCR-SSP. No association was observed between the risk of acute graft-versus-host disease (GVHD) and these SNP. However, our findings suggest that the polymorphism of promoter gene TNFA-238GA is associated with the occurrence and severity of chronic GVHD. The probability of chronic GVHD in patients with GA genotype at position -238 of TNFA gene is 91.7% in contrast to 59.4% in patients with GG genotype (P = 0.038). In patients with donor GA genotype the probability of chronic GVHD is 90.8%, and 57.9% in patients with donor GG genotype (P = 0.038). The probability of extensive chronic GVHD in patients with TNFA-238GA is 91.7% compared with 46.3% in patients with TNFA-238GG (P = 0.0046). In patients with donor GA genotype at position -238 of the TNFA gene, it is 81.7%, compared with 44.5% in patients with donor GG genotype (P = 0.016). However, further studies with more patients are required to identify cytokine gene polymorphisms and their association with transplant-related complication in Brazil, particularly due to ethnic background, the relatively low power of detection of genetic markers of this study, and the complexity of the MHC region.

Immature monocytes from G-CSF-mobilized peripheral blood stem cell collections carry surface-bound IL-10 and have the potential to modulate alloreactivity

Production of the anti-inflammatory cytokine IL-10 by monocytes has been implicated as a probable negative regulator of graft-versus-host disease (GvHD) in patients undergoing allogeneic stem cell transplants (SCT). Monocytes from G-CSF-mobilized peripheral blood stem cell (gmPBSC) collections have been reported to produce more IL-10 than unmobilized monocytes in response to proinflammatory factors such as LPS. Why this should occur is unclear. In this study, monocyte phenotype and IL-10 localization and release were investigated in PB mononuclear cells (MNC) from 27 healthy donors mobilized for allogeneic SCT and from 13 patients with hematological malignancies mobilized for autologous SCT. All isolates contained elevated total percentages of monocytes in comparison with unmobilized PB, a high proportion of which displayed an immature phenotype. Stimulation of gmPB MNC with an inflammatory stimulus [fixed Staphylococcus aureus cells (SAC)] induced rapid up-regulation of CD14, indicating conversion to mature status. Localization studies indicated that IL-10 was predominantly present, bound on the surface of CD64(+)/CD14(low/neg) immature monocytes. Inflammatory stimuli (LPS, polyinosinic:polycytidylic acid, or SAC) induced release of variable quantities of IL-10 from the cell surface. MNC, separated into surface IL-10-positive or -negative fractions, differed in their ability to stimulate alloreactivity in MLR, and IL-10(+) MNC induced significantly lower levels of proliferation than IL-10(-) MNC. Thus, the subset of immature monocytes carrying surface-bound IL-10 in gmPB has the potential to modulate alloreactivity and GvHD after allogeneic SCT through cell-to-cell contact and released IL-10.

The clinical spectrum of acute graft-versus-host disease

Acute graft-versus-host disease (GVHD), initiated by the reaction of donor T lymphocytes against nonshared recipient antigens, typically leads to a clinical syndrome characterized by cutaneous eruptions and intestinal and hepatic dysfunction. These three organ systems are considered in the clinical grading of acute GVHD. However, other targets may be involved. With conventional transplant conditioning regimens and in vivo prophylaxis, GVHD becomes clinically manifest within 2 to 4 weeks. With reduced-intensity conditioning, the onset of acute GVHD may be delayed until 2 to 3 months after transplantation. Hyperacute GVHD may occur within a week of transplantation after severely human leukocyte antigen (HLA)-mismatched transplants or transplants without GVHD prophylaxis. There is no reliable laboratory test for acute GVHD, and the diagnosis is based on clinical assessment.

Relationship between cytokine gene polymorphisms and graft-versus-host disease after allogeneic stem cell transplantation in a Brazilian population

Graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem cell transplantation (HSCT), and cytokines are recognized as important mediators of GVHD. Polymorphisms in the regulatory regions of several cytokine genes have been associated with a number of immune diseases as well as organ transplant complications. In this study we have investigated the role of tumor necrosis factor-alpha(-308), interleukin (IL)-6(-174), IL-10(-1082, -819, -592), Interferon-gamma(-874), and transforming growth factor-beta1(+869, +915) polymorphisms on HSCT outcome. Donor/recipient genotypes were analyzed by polymerase chain reaction with sequence specific primers (PCR-SSP). Although we have found a small number of low IL-6, a polymorphism at position -174 of the recipient and donor IL-6 gene was associated with the increased incidence of chronic GVHD. Therefore, this study emphasizes the probable potential role of genetic variability of donor and recipient in determining outcome after transplantation.

Genetic polymorphisms predicting the outcome of bone marrow transplants

Analysis of non-histocompatibility leucocyte antigen (HLA) functional genomics, together with conventional risk factors in haematopoietic stem cell transplantation (HSCT) can lead to predicting outcome in HLA-matched sibling transplant recipients. Polymorphisms of cytokine genes including tumour necrosis factor alpha, interleukin-10, interferon gamma and interleukin (IL)-6, associate with more severe acute graft-versus-host disease (aGvHD). Donor genotype for IL-1 receptor antagonist (IL-1Ra) has been associated with reduced aGvHD severity. Other genotypes (patient IL-1Ra, IL-6 and donor IL-1 alpha) have been associated with chronic GvHD, or overall survival (Vitamin D receptor and oestrogen receptor). Polymorphisms within genes associated with host defence/inflammatory responses (mannose binding lectin genes, myeloperoxidase genes and the FC gamma receptors) have been associated with infections. Polymorphisms of pharmacogenes, such as methylenetetrahydrofolate-reductase, have been associated with aGvHD and other post-transplant complications. The NOD2 gene polymorphism, associated with Crohn's disease, has been shown to be associated with risk of gut GvHD. The majority of the studies have been carried out in single centre HLA-matched sibling cohorts and in relatively few matched unrelated donor transplants. This review gives an overall perspective of the current field of non-HLA genetics with regard to HSCT outcome, clinical relevance and potential application of the results to clinical management of HSCT.

Polymorphisms of interleukin-1alpha constitute independent risk factors for chronic graft-versus-host disease after allogeneic bone marrow transplantation

The interleukin-1 (IL-1) family of cytokines is widely involved in inflammatory processes and diseases with an inflammatory component. Polymorphisms of the IL-1alpha, IL-1beta and IL-1Ra genes have been implicated in a number of autoimmune or inflammatory conditions, with polymorphism of the IL-1Ra gene showing association with severity of graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). We compared the clinical outcomes (GVHD and survival) of 115 patients after human leucocyte antigen (HLA)-identical sibling allogeneic BMT with their genotype for two polymorphisms present in the IL-1alpha gene, which have been implicated in immune-related pathology. Possession of allele 2 of the IL-1alpha-889 polymorphism and allele 2 of the IL-1alpha variable number tandem repeat (VNTR) polymorphism in the donor genotype was associated with the occurrence of chronic, but not acute GVHD. A local normal population was also genotyped for these polymorphisms, and subsequent analysis identified conserved haplotypes in this gene region. Haplotypes containing allele 2 at both IL-1alpha-889 and IL-1alpha VNTR loci were extremely uncommon, suggesting that both risk alleles would be inherited independently. Both loci could therefore function as independent disease association markers. The polymorphisms of the IL-1alpha gene could be used to predict chronic GVHD in HLA-matched sibling transplants alongside clinical risk factors.

Oestrogen receptor alpha gene polymorphism associates with occurrence of graft-versus-host disease and reduced survival in HLA-matched sib-allo BMT

Oestrogen receptors mediate the cellular response to oestrogens and related compounds and promote a wide range of effects on haemopoiesis. Polymorphisms of the oestrogen receptor genes have previously been associated with variation in bone mineral density, likelihood of fractures, risk of developing Alzheimer's disease, endometrial cancer and response to hormone replacement therapy. We examined the polymorphisms in both ERalpha and ERbeta genes in 108 patients receiving a bone marrow transplant from an HLA-matched sibling donor, and compared ER genotype with outcomes of occurrence of graft-versus-host disease (GVHD) and survival using logistic regression analysis. Polymorphism of ERalpha (presence of the PX haplotype (PvuII-XbaI RFLP) of intron 1), but not ERbeta, in the patient genotype associates with occurrence of acute GVHD and with lower overall survival, following correction for known clinical and genotypic risk features. Analysis of ER genotype prior to transplant might therefore inform on a patient's likelihood of developing post-transplant complications. Variation in transplant performance because of ER genotype suggests an underlying role for oestrogens in the pathophysiology of transplant-related complications, and suggests that oestrogen-related therapy may offer a new modality of post-transplant support.

New Developments in Allotransplant Immunology

After allogeneic stem cell transplantation, the establishment of the donor’s immune system in an antigenically distinct recipient confers a therapeutic graft-versus-malignancy effect, but also causes graft-versus-host disease (GVHD) and protracted immune dysfunction. In the last decade, a molecular-level description of alloimmune interactions and the process of immune recovery leading to tolerance has emerged. Here, new developments in understanding alloresponses, genetic factors that modify them, and strategies to control immune reconstitution are described.

In Section I, Dr. John Barrett and colleagues describe the cellular and molecular basis of the alloresponse and the mechanisms underlying the three major outcomes of engraftment, GVHD and the graft-versus-leukemia (GVL) effect. Increasing knowledge of leukemia-restricted antigens suggests ways to separate GVHD and GVL. Recent findings highlight a central role of hematopoietic-derived antigen-presenting cells in the initiation of GVHD and distinct properties of natural killer (NK) cell alloreactivity in engraftment and GVL that are of therapeutic importance. Finally, a detailed map of cellular immune recovery post-transplant is emerging which highlights the importance of post-thymic lymphocytes in determining outcome in the critical first few months following stem cell transplantation. Factors that modify immune reconstitution include immunosuppression, GVHD, the cytokine milieu and poorly-defined homeostatic mechanisms which encourage irregular T cell expansions driven by immunodominant T cell–antigen interactions.

In Section II, Prof. Anne Dickinson and colleagues describe genetic polymorphisms outside the human leukocyte antigen (HLA) system that determine the nature of immune reconstitution after allogeneic stem cell transplantation (SCT) and thereby affect transplant outcomethrough GVHD, GVL, and transplant-related mortality. Polymorphisms in cytokine gene promotors and other less characterized genes affect the cytokine milieu of the recipient and the immune reactivity of the donor. Some cytokine gene polymorphisms are significantly associated with transplant outcome. Other non-HLA genes strongly affecting alloresponses code for minor histocompatibility antigens (mHA). Differences between donor and recipient mHA cause GVHD or GVL reactions or graft rejection. Both cytokine gene polymorphisms (CGP) and mHA differences resulting on donor-recipient incompatibilities can be jointly assessed in the skin explant assay as a functional way to select the most suitable donor or the best transplant approach for the recipient.

In Section III, Dr. Nelson Chao describes non-pharmaceutical techniques to control immune reconstitution post-transplant. T cells stimulated by host alloantigens can be distinguished from resting T cells by the expression of a variety of activation markers (IL-2 receptor, FAS, CD69, CD71) and by an increased photosensitivity to rhodamine dyes. These differences form the basis for eliminating GVHD-reactive T cells in vitro while conserving GVL and anti-viral immunity. Other attempts to control immune reactions post-transplant include the insertion of suicide genes into the transplanted T cells for effective termination of GVHD reactions, the removal of CD62 ligand expressing cells, and the modulation of T cell reactivity by favoring Th2, Tc2 lymphocyte subset expansion. These technologies could eliminate GVHD while preserving T cell responses to leukemia and reactivating viruses.

Cytokines, viruses, and graft-versus-host disease

Proinflammatory cytokines released by host tissues during conditioning treatment and interferon gamma released from donor T cells play a major role in acute graft-versus-host disease (GVHD). In the past year the interaction of cytokines has been elucidated further. Host antigen-presenting cells play a key role in the induction of allogeneic recognition. Their activity is modulated by cytokines such as flt3-ligand, viruses, and donor T cells. Expansion of donor T cells is crucial for the pathogenesis of acute GVHD. Cytokines of the T helper 1 response-IFN-gamma, IL-12, and IL-18-regulate the expansion of donor and host cells via the induction of Fas and FasL and subsequent apoptosis. However TNF-alpha, FasL, and IL-1 also cause damage to target cells. Cytokine and receptor gene polymorphism has an impact on the activity of both host and donor cell activation. Genetic factors, conditioning treatment, lipopolysaccharides (LPS) from gram-negative microorganisms, viral infections, and donor T cells determine the activity level of host antigen-presenting cells and macrophages, which have an impact on acute GVHD and other complications of allogeneic stem cell transplantation.

New concepts about graft-versus-host and graft-versus-leukaemia-reactions. A summary of the 5th International Symposium held in Munich, 21 and 22 March 2002

The Fifth International Symposium on Graft-versus-Host and Graft-versus-Leukemia Reactions was held on 21 and 22 March 2002 in the University Hospital (Klinikum Grosshadern) of the University of Munich. As in previous years, it was dedicated to the encounter of scientists and clinicians involved in hematopoietic cell transplantation. This year's symposium focused on the characterization of stem cells potentially expanding the use of hematopoietic stem cells and on gene therapy. The immunology section dealt with mechanisms of tolerance, and the characterization of minor histocompatibility antigens presented by major histocompatibility molecules. Further important topics were cytokines and dendritic cells. In 1 and 1/2 days of intense work, the invited speakers, chairmen, authors and an active audience experienced an exciting exchange of ideas and collaboration. Again, new impulses were given for basic research and clinical transplantation. The authors would like to express their deep appreciation and thanks to all participants of this symposium.

Recipient cytokine genotypes for TNF-alpha and IL-10 and the minor histocompatibility antigens HY and CD31 codon 125 are not associated with occurrence or severity of acute GVHD in unrelated cord blood transplantation: a retrospective analysis

BACKGROUND

In HLA-identical sibling bone marrow transplantation, certain recipient cytokine gene polymorphism genotypes and minor histocompatibility differences influence the occurrence and severity of acute graft-versus-host disease (aGvHD). The present study investigated the role of cytokine tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 gene polymorphisms HY, HA-1, and CD31 minor histocompatibility antigen (mHag) mismatch in the development of aGvHD after unrelated cord blood (CB) transplant (CBT).

METHODS

DNA samples of 115 CB recipients and their unrelated CB grafts were analyzed for genotype associated with TNF-alpha (TNFd3/d3) and IL-10 (IL-10(-1064), 11-16) and for disparities in major and three minor histocompatibility antigens, HY, HA-1, and CD31 codon 125. Results were correlated with the incidence of aGvHD grades II to IV.

RESULTS

Neither the donor nor the recipient GvHD risk alleles TNFd3/d3 and IL-10(-1064) (11-16) were associated with the development of aGvHD grades II to IV and I to IV. Because of the heterogeneity of CBTs, the data were reanalyzed separately for patients with malignancies (n=83) or with inborn errors (n=24). No significant association was observed between the severity of aGvHD and the possession of either TNFd3/d3 or IL-10 (11-16) genotypes. Mismatches for the mHags HY, HA-1, and CD31 exon 125 between donor and recipient did not associate with aGvHD grades II to IV.

CONCLUSIONS

In contrast to HLA-identical sibling bone marrow transplantation, in mismatched unrelated CBT, neither the cytokine genotypes TNFd3/d3 alone or in combination with IL-10(-1064) alleles nor the minor histocompatibility antigens HY, HA-1, and CD31 exon 125 were associated with aGvHD grades II to IV. Further determination of the cytokine gene polymorphism genotypes in CBTs compared with bone marrow transplants may identify those polymorphisms that could be potential predictive markers for the occurrence of aGvHD.

Interleukin-10 modulation of alloreactivity and graft-versus-host reactions

BACKGROUND

The biological properties of interleukin (IL)-10 in tolerance induction and inhibition of alloreactivity have suggested a therapeutic use of this cytokine as an additional or alternative prophylaxis for graft-versus-host disease (GvHD). However, the effects of exogenous IL-10 on GvHD are mainly studied in animal models, and the results remain conflicting. This study aims to demonstrate, for the first time, whether the addition of exogenous IL-10 can reduce the severity of graft-versus-host reactions (GvHR) in humans.

METHODS

The regulatory role of exogenous IL-10 in GvHR was investigated using an in vitro human skin explant model. The effects of IL-10 on skin GvHR were tested in parallel with allo-antigen induced T-cell proliferation, cytolytic reactivity, and cytokine production.

RESULTS

In the presence of IL-10, the mixed lymphocyte reaction (MLR) primed responder cells showed significantly lower proliferative and cytolytic responses compared with the responder cells from the control MLR carried out in the absence of IL-10. The responder cells from IL-10 containing MLR induced significantly less severe skin GvHR and displayed a significantly reduced T-cell activation and cytokine production. A significant correlation was observed between the levels of TNF-alpha production and the sensitivity to IL-10 modulation of GvHR.

CONCLUSIONS

The addition of exogenous IL-10 strongly inhibited the broad alloreactivity initiated by primary MLR and significantly reduced the overall severity of skin GvHR induced by MLR primed responder cells. Responder cells producing high TNF-alpha following allogeneic stimulation appeared to be less sensitive to IL-10 modulation of GvHR.

Vitamin D receptor gene polymorphism associates with graft-versus-host disease and survival in HLA-matched sibling allogeneic bone marrow transplantation

We investigated the role of polymorphism of the vitamin D receptor (VDR) gene in HLA-matched sibling BMT for polymorphisms previously associated with human disease pathology. In intron 8 of the VDR gene, the B and A alleles of the BsmI and ApaI RFLPs were found to associate with reduced aGVHD when present in the patient's genotype. Logistic regression analysis demonstrated that patient VDR genotype, along with previously identified IL-10(-1064) and IFN-gamma genotype to be risk factors for severe acute GVHD. The A allele also associates with increased likelihood of death when present in the donor genotype (AA vs Aa or aa, hazard ratio 2.03, P = 0.0232). In patients who received increased prophylaxis with multi-agent therapy, patients whose graft was from a donor with an AA genotype had a substantially worse survival than patients whose graft was from a donor with a non-AA genotype (hazard ratio 12.93, P < 0.0001). Analysis of VDR genotype in prospective BMT recipients could indicate patients at risk of severe aGVHD. Analysis of VDR genotype in prospective BMT donors may identify individuals who have greater transplant-related mortality, and also allow appropriately restricted use of increased immunosuppressive prophylaxis.