Human Leukocyte Antigen DR15 Is Associated with Reduced Relapse Rate and Improved Survival after Human Leukocyte Antigen-Identical Sibling Hematopoietic Stem Cell Transplantation

Antibody-mediated pathogenesis of chronic GVHD through DBY/HLA class II complexes and induction of a GVL effect

Chronic graft-versus-host disease (cGVHD) is a multiorgan syndrome with clinical features resembling those of autoimmune diseases. Thus, understanding commonalities in the pathophysiology of cGVHD and autoimmune diseases, such as the presence of disease-risk HLA alleles, is imperative for developing novel therapies against cGVHD. Alloantibodies against H-Y antigens encoded on the Y-chromosome are well-described risk factors for cGVHD in female-to-male transplantation. However, because H-Y antigens generally localize intracellularly in the male reproductive organs, how they emerge at affected organ levels remains elusive. Here, by analyzing nationwide registry data stratified per donor-recipient sex, we identified specific HLA class II alleles that contributed to susceptibility to male cGVHD after transplantation from HLA-identical female siblings (HLA-DRB1∗15:02: hazard ratio, 1.28; 95% confidence interval, 1.03-1.58; P = .025). Coexpression of HLA-DRB1∗15:02 efficiently transported full-length H-Y antigens, especially DBY, to the surface. The presence of alloantibodies against DBY/HLA class II complexes significantly predicted the occurrence of cGVHD (68.8% vs 31.7% at 1 year; P = .002). Notably, the ability of HLA class II molecules to transport and present DBY to alloantibodies was closely associated with the susceptibility of HLA class II alleles to cGVHD. DBY specifically colocalized with HLA class II molecules on the dermal vascular endothelium in cGVHD and provoked complement-dependent cytotoxicity. Moreover, these complexes were observed in some male leukemic cells. Altogether, these findings suggest that vascular endothelial cells facilitate alloantibody-mediated cGVHD and highlight that alloantibodies against DBY/HLA class II complexes could be common targets for cGVHD and a graft-versus-leukemia effect.

Alternative donor strategy in unrelated hematopoietic stem cell transplantation - outcome with mismatched donors

PURPOSE

This study retrospectively investigated the association between the level of human leukocyte antigen (HLA) mismatches (MMs), direction of disparities and differences at particular HLA locus on clinical outcomes of hematopoietic stem cell transplantation (HSCT). Investigated outcomes were overall survival (OS) and disease-free survival (DFS), graft-versus-host disease (GvHD), relapse and non-relapse mortality (NRM).

PATIENTS AND METHODS

Study cohort included 108 adult patients transplanted between 2011 and 2021 and their 9/10 mismatched unrelated donors (MMUD). All individuals were typed for HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci using Polymerase Chain Reaction-Sequence Specific Primers, PCR-Sequence Based Typing and Next-Generation Sequencing. All statistical analyses were done in the MedCalc software, version 19.2.6.

RESULTS

Patients with MMs at HLA-B locus demonstrated worse OS (P ​= ​0.0440, HR ​= ​2.00, n ​= ​20). Absence of HLA-DRB5 was associated with a higher incidence of GvHD (P ​= ​0.0112, HR ​= ​1.93, n ​= ​67). A lower incidence of GvHD was observed in patients with HLA class II MMs compared to patients with HLA class I MMs (P ​= ​0.0166, HR ​= ​1.94, n ​= ​29). Finally, analysis of PIRCHE score (PS) impact revealed that patients with HLA class II PS ​> ​10 in GvH direction showed higher incidence of GvHD compared to patients with HLA class II PS ​< ​10 (P ​= ​0.0073, HR ​= ​2.01, n ​= ​55).

CONCLUSION

Obtained results undisputedly indicate the necessity to further investigate this matter on a larger patient group, with focus on specific HLA alleles to define precisely priority criteria for selecting the best donor for all patients, thus improving the outcome of HSCT with an MMUD.

Individual HLAs influence immunological events in allogeneic stem cell transplantation from HLA-identical sibling donors

In allogeneic hematopoietic stem cell transplantation (allo-HSCT), the effects of patient and donor human leukocyte antigen (HLA) matching status on graft-versus-host disease (GVHD) have been extensively elucidated, but the effects of specific HLAs on acute GVHD remain unclear. Using data from a Japanese registry, we retrospectively analyzed 4392 patients with leukemia or myelodysplastic syndrome who received transplants from HLA-identical sibling donors to investigate the effects of HLAs on acute GVHD. From unbiased searches of HLA-A, -B, and -DR, HLA-B60 was significantly associated with an increased risk of grades II-IV acute GVHD (HR, 1.34; 95% CI, 1.13-1.59; P = 0.001). In contrast, HLA-B62 was significantly associated with a decreased risk of grades II-IV (HR, 0.73; 95% CI, 0.62-0.87; P < 0.001) and III-IV acute GVHD (HR, 0.63; 95% CI, 0.46-0.87; P = 0.005). The risk of leukemia relapse was significantly higher in HLA-B62-positive patients than in HLA-B62-negative patients (HR, 1.23; 95% CI, 1.05-1.43; P = 0.01). Both HLA-B60 and -B62 did not affect overall survival. The findings of this study may by implication suggest the possibility that the effects of specific HLAs on transplant outcomes may reflect inherent biological features, and thus consideration of specific HLAs may be helpful to predict transplant outcomes.

Impact of HLA Alleles on Outcomes of Allogeneic Transplantation for B Cell Non-Hodgkin Lymphomas: A Center for International Blood and Marrow Transplant Research Analysis

Even in the modern era of targeted therapies, allogeneic hematopoietic stem cell transplantation (allo-HCT) can offer a chance of extended survival in B cell non-Hodgkin lymphoma (B-NHL) patients who relapse after or are deemed ineligible for autologous transplantation. A better understanding of the factors influencing the graft-versus-lymphoma (GVL) response would be useful in identifying B-NHL patients who may benefit from allo-HCT. Based on prior single-center reports, we hypothesized that certain HLA alleles, or haplotypes, may be associated with superior GVL compared with others after allo-HCT. To test this possibility we retrospectively evaluated whether the presence of HLA-A2, HLA-C1C1, HLA-DRB1*01:01, or HLA-DRB1*13 alleles or the presence of HLA-A1+, HLA-A2-, and HLA-B44- haplotypes is associated with outcomes in a cohort of 1314 HLA-8/8 matched sibling or unrelated donor HCT for relapsed/refractory B-NHL. We observed no significant association between any HLA allele or haplotype and overall survival or any of the secondary endpoints. In conclusion, this study represents the largest reported series of allo-HCT outcomes of B-NHL patients based on HLA type. Identification of other variables will be required to delineate the immunologic impact of donor-host interactions on outcomes of allo-HCT for B-NHL.

High-risk HLA alleles for severe acute graft-versus-host disease and mortality in unrelated donor bone marrow transplantation

HLA molecules play an important role for immunoreactivity in allogeneic hematopoietic stem cell transplantation. To elucidate the effect of specific HLA alleles on acute graft-versus-host disease, we conducted a retrospective analysis using 6967 Japanese patients transplanted with T-cell-replete marrow from an unrelated donor. Using unbiased searches of patient and donor HLA alleles, patient and/or donor HLA-B*51:01 (patient: HR, 1.37,P<0.001; donor: HR, 1.35,P<0.001) and patient HLA-C*14:02 (HR, 1.35,P<0.001) were significantly associated with an increased risk of severe acute graft-versus-host disease. The finding that donor HLA-C*14:02 was not associated with severe acute graft-versus-host disease prompted us to elucidate the relation of these high-risk HLA alleles with patient and donor HLA-C allele mismatches. In comparison to HLA-C allele match, patient mismatched HLA-C*14:02 showed the highest risk of severe acute graft-versus-host disease (HR, 3.61,P<0.001) and transplant-related mortality (HR, 2.53,P<0.001) among all patient mismatched HLA-C alleles. Although patient HLA-C*14:02 and donor HLA-C*15:02 mismatch was usually KIR2DL-ligand mismatch in the graft-versus-host direction, the risk of patient mismatched HLA-C*14:02 for severe acute graft-versus-host disease was obvious regardless of KIR2DL-ligand matching. The effect of patient and/or donor HLA-B*51:01 on acute graft-versus-host disease was attributed not only to strong linkage disequilibrium of HLA-C*14:02 and -B*51:01, but also to the effect of HLA-B*51:01 itself. With regard to clinical implications, patient mismatched HLA-C*14:02 proved to be a potent risk factor for severe acute graft-versus-host disease and mortality, and should be considered a non-permissive HLA-C mismatch in donor selection for unrelated donor hematopoietic stem cell transplantation.

16th IHIW: international histocompatibility working group in hematopoietic cell transplantation

The International Histocompatibility Working Group is a collaborative international effort to understand the HLA and non-HLA genetics of the transplantation barrier. The Working Group is comprised of experts in the fields of histocompatibility and immunogenetics, hematopoietic cell transplantation and outcomes research. Data for 25 855 unrelated donor transplants were submitted in support of research studies for the 16th International Histocompatibility Workshop. Active investigation is in progress in seven key areas: the impact of HLA matching, role of race and ethnicity, identification of permissible HLA mismatches, haplotype-associated determinants, minor histocompatibility antigens, immune response genes and KIR genetics. New hypotheses for the 16th workshop were developed for immunogenetic studies in cord blood and haploidentical-related donor transplantation.

Genetics of graft-versus-host disease: the major histocompatibility complex

Graft-versus-host disease (GVHD) is a potentially life-threatening complication of allogeneic hematopoietic cell transplantation. Many genes are presumed to be involved in GVHD, but the best characterized genetic system is that of the human major histocompatibility complex (MHC) located on chromosome 6. Among the hundreds of genes located within the MHC region, the best known and characterized are the classical HLA genes, HLA-A, C, B, DRB1, DQB1, and DPB1. They play a fundamental role in T cell immune responses, and HLA-A, C, and B also function as ligands for the natural killer cell immunoglobulin-like receptors involved in innate immunity. This review highlights the state-of-the art in the field of histocompatibility and immunogenetics of the MHC with respect to genetic risk factors for GVHD.

Allogeneic hematopoietic cell transplantation for myelodysplastic syndrome: the past decade

Hematopoietic cell transplantation (HCT) is the only therapy with curative potential for patients with myelodysplastic syndrome. Many conditioning regimens have been developed that, along with the use of cord blood or HLA-haploidentical donors, allow doctors to offer HCT to a growing proportion of patients. New classification schemes identify more narrowly characterized risk groups, which may facilitate decisions with regard to HCT. Disease stage and cytogenetics remain the major determinants of HCT outcome. The use of peripheral blood progenitor cells may offer an advantage over marrow for engraftment and relapse prevention, but graft-versus-host disease remains a problem. The age of patients undergoing HCT has increased significantly over the past 25 years, and comorbid conditions are the major patient characteristic impacting transplant success. Recent studies show that drugs used in the non-HCT setting may be beneficial in the context of HCT.

HLA DR15 antigen status does not impact graft-versus-host disease or survival in HLA-matched sibling transplantation for hematologic malignancies

The HLA class II DRB1 antigen DR15 is an important prognostic marker in immune-mediated marrow failure states. DR15 has also been associated with favorable outcomes (reduced acute graft-versus-host disease [aGVHD] and relapse) after allogeneic hematopoietic cell transplant. To elucidate the impact of DR15 on transplantation outcomes, we conducted a retrospective study of 2891 recipients of first allogeneic stem cell transplant from HLA-matched sibling donors for the treatment of acute leukemia, chronic myeloid leukemia, or myelodysplastic syndrome (MDS) between 1990 and 2007. All patients received conventional myeloablative conditioning, T-replete grafts, and cyclosporine plus methotrexate-based GVHD prophylaxis. DNA-based HLA typing allowed categorization of 732 patients (25.3%) as positive and 2159 patients (74.7%) as negative for DRB1*15:01 or *15:02 (DR15). There were no significant differences in baseline characteristics between the HLA DR15 positive and negative groups. In univariate analysis, HLA-DR15 status had no impact on neutrophil engraftment, aGVHD, chronic GVHD (cGVHD), treatment-related mortality, relapse, disease-free survival, or overall survival (OS). In multivariate analysis, DR15 status showed no significant difference in aGVHD, cGVHD, OS, or relapse. In conclusion, DR15 status had no impact on major HLA-matched sibling donor hematopoietic cell transplant outcomes in this large and homogenous cohort of patients with leukemia and MDS.

HLA-matched sibling transplantation for severe aplastic anemia: impact of HLA DR15 antigen status on engraftment, graft-versus-host disease, and overall survival

The HLA class II DRB1 antigen DR15 (common alleles *1501, *1502) is an important marker in the pathobiology of severe aplastic anemia (SAA). We studied 1204 recipients of HLA-matched sibling bone marrow transplantation for SAA to determine whether HLA DR15 status (as determined by allele-level typing) affected hematopoietic recovery, graft-versus-host disease (GVHD), or overall survival (OS). In multivariate analysis, secondary graft failure rate at 2 years was lower in patients who were HLA DR15+ (hazard ratio = 0.46, P = .01). However, neutrophil recovery at day -28, platelet recovery at day -100, acute GVHD, chronic GVHD, and overall mortality were independent of DR15 status. The 5-year probabilities of OS, after adjusting for age, race, performance score, transplant-conditioning regimen, and year of transplantation, were 78% and 81% for patients who were HLA DR15+ and HLA DR15-, respectively (P = .35). In conclusion, DR15 status is associated with secondary graft failure after HLA-matched sibling bone marrow transplantation for SAA but has no significant impact on survival.

Association between human leukocyte antigens and graft-versus-host disease occurrence after allogenic hematopoietic stem cell transplantation

CONTEXT AND OBJECTIVE

Graft-versus-host disease (GVHD) is one of the complications following allogenic stem cell transplantation. This study investigated an association between human leukocyte antigen (HLA) and the occurrence of acute and chronic GVHD in patients who had received stem cell transplantations from HLA-identical siblings.

DESIGN AND SETTING

Retrospective study at Hematology and Hemotherapy Center, Universidade Estadual de Campinas (Unicamp).

METHODS

The participants were 176 patients whose first transplant was between 1997 and 2009. HLA genotyping was performed serologically and using the polymerase chain reaction with specific primer sequence.

RESULTS

Acute GVHD was positively associated with HLA-A10 (P = 0.0007), HLA-A26 (P = 0.002), B55 (P = 0.001), DRB1*15 (P = 0.0211) and DQB1*05 (P = 0.038), while HLA-B16 (P = 0.0333) was more frequent in patients without acute GVHD. Chronic GVHD was positively associated with HLA-A9 (P = 0.01) and A23 (P = 0.0292) and negatively with HLA-A2 (P = 0.0031) and B53 (P = 0.0116). HLA-B35 (P = 0.0373), B49 (P = 0.0155) and B55 (P = 0.0024) were higher in patients with acute GVHD grade 3 or above, than in other patients. In patients with extensive chronic GVHD, HLA-A9 (P = 0.0004), A24 (P = 0.0059) and A26 (P = 0.0411) were higher than in other patients, while HLA-A2 was lower (P = 0.0097).

CONCLUSION

This study suggests that HLA can influence the incidence and severity of acute and chronic GVHD. However, a study with a better design and more patients will be needed to confirm these results.

Tumor necrosis factor polymorphism affects transplantation outcome in patients with myelodysplastic syndrome but not in those with chronic myelogenous leukemia, independent of the presence of HLA-DR15

Both the presence of HLA-DR15 and tumor necrosis factor (TNF)-α levels have been reported to affect outcome after hematopoietic cell transplantation (HCT). Patients with a myelodysplastic syndrome (MDS) show a high prevalence of HLA-DR15 and express high levels of TNF-α in the bone marrow. The present analysis involving 7950 patients showed an HLA-DR15 frequency of 31% in patients with MDS, compared with only 23% in patients with chronic myelogenous leukemia (CML). HLA-DR15 was more prevalent in Caucasian patients than in non-Caucasian patients (P = .01). The numbers of patients in the non-Caucasian subgroups were too small to allow further analysis. Among Caucasian patients with MDS and CML, the presence of HLA-DR15 did not significantly affect the occurrence of graft-versus-host disease, relapse, nonrelapse mortality (NRM), or survival. However, there was a significant correlation between DR15 and TNF polymorphisms at position -308 among patients with MDS, and the TNF-308 AG genotype conferred an increased risk of NRM compared with the GG genotype (hazard ratio [HR], 1.49; P = .02), even after adjusting for DR15. Conversely, the TNF-863 AA genotype was correlated with decreased overall mortality and NRM compared with the CC genotype (HR, 0.36, P = .04 vs HR, 0.13, P = .04), even after adjusting for DR15. There was no significant association between TNF-308 or -863 polymorphisms and transplantation outcome in CML patients. These results suggest that TNF polymorphisms, but not DR15, affect transplantation outcome in a disease-dependent manner.

Impact of highly conserved HLA haplotype on acute graft-versus-host disease

Although the effects of human leukocyte antigen (HLA) locus matching on clinical outcome in unrelated hematopoietic stem cell transplantations have been characterized, the biologic implications of HLA haplotypes have not been defined. We demonstrated the genetic fixity of Japanese conserved extended haplotypes by multi-single nucleotide polymorphism analysis in 1810 Japanese donor-recipient pairs matching with HLA-A, -B, -C, -DRB1, and -DQB1 alleles. Three major Japanese conserved extended haplotypes (named HP-P1, HP-P2, and HP-P3) were essentially completely conserved at least in the 3.3-Mb HLA region from HLA-A to -DPB1, and extended far beyond HLA-A. The risk of acute graft-versus-host disease (GVHD) of these HLA haplotypes was assessed with multivariate Cox regression in 712 patients transplanted from HLA fully (HLA-A, B, C, DRB1, DQB1, and DPB1) matched unrelated donors. HP-P2 itself reduced the risk of grade 2 to 4 acute GVHD (hazard ratio [HR] = 0.63; P = .032 compared with HP-P2-negative), whereas HP-P3 tended to increase the risk (HR = 1.38; P = .07). Among 381 patients with HP-P1, HP-P1/P3 (HR = 3.35; P = .024) significantly increased the risk of acute GVHD compared with homozygous HP-P1. This study is the first to demonstrate that a genetic difference derived from HLA haplotype itself is associated with acute GVHD in allogeneic hematopoietic stem cell transplantation.

Acquired immune mediated aplastic anemia: is it antineoplastic?

There is increasing evidence that autoimmunity can inhibit growth of solid tumors. We propose that anti-tumor activity also operates in autoimmunity against hematopoietic stem cells in acquired aplastic anemia (AA). Reduction/dysfunction of regulatory T cells (T(REG)) in AA - rather than being the primary event - could be a response to insufficient or failing anti-tumor reactivity in predisposed individuals, causing elimination of tumor cells and collateral damage to adjacent normal hematopoietic tissue. This pathophysiological mechanism could also apply to otherwise unexplained pancytopenic syndromes which frequently occur in patients with leukemia and lymphoma and non-hematological malignancies. Observations supporting an anti-tumor effect of marrow hypoplasia/aplasia are presented and illustrated with case reports. The conclusion would be that pancytopenia occurring in AA or in AA-like syndromes reflects an ongoing immune reaction against underlying malignancy or infection.

Human leukocyte antigen DR4 is associated with inferior progression-free survival following allogeneic hematopoietic stem cell transplantation for lymphoid malignancies

The Class II human leukocyte antigen (HLA) DRB1 antigen DR4 is associated with autoimmune disorders and response to cyclosporine immunosuppression in T-lymphoproliferative disorders. We retrospectively reviewed the role of HLA DR4 on outcomes in 77 related and 22 unrelated consecutive first HLA-matched alloHSCT patients with lymphoid malignancies treated between 1992 and 2003. HLA DRB1 typing was determined by molecular (n = 69) or serologic (n = 30) methods. The proportion of patients with one HLA DR4 antigen was 18% (18/99). At a median follow-up of 5.6 years, there were no significant differences in aGvHD, cGvHD and OS between the HLA DR4 positive versus negative patients in any disease or donor subgroups. Nine of 18 (50%) DR4 positive patients and 20 of 81 (25%) DR4 negative patients had disease progression post HSCT (p = 0.033). Progression-free survival (PFS) at 3 years was 29% in the DR4 positive group and 70% in the DR4 negative group (p = 0.004). In univariate and multivariate analyses, DR4 positivity was the only significant factor associated with PFS (RR = 3.2, p = 0.007). Our results suggest that in addition to the known role of HLA DRB1 disparity in mediating histocompatibility, HLA DR4 is associated with inferior PFS in patients with lymphoid malignancy undergoing alloHSCT.

Autoimmunity and malignancy in hematology—More than an association

Several associations between hematological malignancies and autoimmunity directed against hematopoietic cells exist. Antibody mediated elimination of mature blood cells such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) are frequent complications of non-Hodgkin lymphomas, most prominently chronic lymphocytic leukemia. Autoimmunity directed against hematopoietic precursor cells is the hallmark of aplastic anemia, but many features of this disease are shared by two related disorders, paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplastic syndrome (MDS). While the clinical associations between hematological malignancy and autoimmunity have been described many decades ago, only in the last several years have the common pathogenetic mechanisms been elucidated. We summarize the recent progress made in understanding how hematological malignancy gives rise to autoimmunity directed against blood cells and vice versa, and illustrate parallels in the etiology of malignant and autoimmune hematological disorders. Specifically, recent progress in the recognition of the association of lymphoproliferative disorders and autoimmunity against mature blood cells, and common pathogenetic background of aplastic anemia, paroxysmal nocturnal hemoglobinuria, and myelodysplastic syndrome are discussed.