Hideki Nakasone

Clinical impact of H-Y alloimmunity

H-Y antigens are a group of minor histocompatibility antigens encoded on the Y-chromosome with homologous H-X antigens on the X-chromosome. The disparate regions of the H-Y antigens are highly immunogenic and play an important role in understanding human alloimmunity. In this review, we investigate the history of H-Y antigen discovery along with their critical contributions in transplantation and pregnancy. In hematopoietic cell transplantation, male recipients with female donors who become seropositive for B-cell responses as H-Y antibodies following transplantation have increased rates of chronic graft-versus-host disease and decreased rates of relapse. Conversely, female patients who receive male kidney allografts are more likely than other gender combinations to develop H-Y antibodies and reject their allografts. Finally, in the setting of pregnancy, mothers who initially gave birth to boys are more likely to have subsequent pregnancy complications, including miscarriages, in association with H-Y antibody development. H-Y antigens continue to serve as a model for alloimmunity in new clinical scenarios. Our development of more sensitive antibody detection and next-generation DNA sequencing promises to further advance our understanding and better predict the clinical consequences of alloimmunity.

Impact of hepatitis C virus infection on clinical outcome in recipients after allogeneic hematopoietic cell transplantation

The impact of hepatitis C virus (HCV) infection on outcomes following allogeneic hematopoietic cell transplantation (HCT) remains a matter of debate. We have retrospectively examined the significance of HCV infection among recipients who received allogeneic HCT, using a Japan transplant outcome registry database between 2006 and 2009. Among 7,831 recipients, 136 were HCV‐positive. The rate of hematopoietic recovery was lower in the HCV‐positive group (neutrophil recovery of 500 × 106/L or higher: 79% vs. 87% at Day 30, Pu2009=u20090.087; platelet recovery of 50 × 109/L or higher: 57% vs. 65% at Day 60, Pu2009=u20090.012). The HCV‐positive group had a significantly higher incidence of nonrelapse mortality 38% vs. 25% at 2 years, Pu2009<u20090.01) and inferior overall survival (41% vs. 51% at 2 years, Pu2009<u20090.01). A multivariate analysis revealed that HCV seropositivity was associated with an independent risk for higher nonrelapse mortality (hazard ratio: 1.65, Pu2009<u20090.01) and inferior overall survival (hazard ratio: 1.39, Pu2009<u20090.01). The incidences of death due to hepatic problems (8% vs. 2%, Pu2009<u20090.01), bacterial infection (10% vs. 4%, Pu2009<u20090.01), or graft failure (5% vs. 2%, Pu2009=u20090.084) tended to be higher in the HCV‐positive group. HCV infection had an adverse impact on the clinical outcome following HCT, especially in the setting of unrelated transplantation. Careful evaluation before embarking on HCT and intensive assessment against complications are warranted in HCV‐infected recipients. Am. J. Hematol. 88:477–484, 2013.

Impact of conditioning intensity and TBI on acute GVHD after hematopoietic cell transplantation

The impact of the conditioning intensity and TBI on acute GVHD (aGVHD) is still a matter of debate. We analyzed 6848 adult recipients who received allogeneic hematopoietic cell transplants (HCT) between 2006 and 2011 in Japan. The subjects were divided into groups who had received myeloablative conditioning (MAC) or reduced-intensity conditioning (RIC), either with or without TBI. There was a significant difference in the incidence of aGVHD 2–4 among the different conditioning types: 39% in TBI-MAC, 35% in TBI-RIC and 32% in both no-TBI MAC and no-TBI-RIC (P<0.001). In a multivariate analysis, TBI-MAC, but not no-TBI MAC, was significantly associated with an increased risk of aGVHD 2–4 (hazard ratio (HR) 1.33, P<0.01), whereas TBI-RIC was associated with an increased risk of GVHD 3–4 (HR 1.36, P=0.048). TBI-MAC and TBI-RIC were significantly associated with skin and gastrointestinal aGVHD. Subgroup analyses demonstrated that not only TBI-MAC, but also TBI-RIC, was significantly associated with aGVHD 2–4 in older patients. Furthermore, high-dose TBI only had an adverse impact on aGVHD 2–4 in HLA-matched HCT. Impacts of intensity and TBI on aGVHD differ by patient backgrounds, and this difference should be considered to establish a risk-adapted strategy for the prevention of aGVHD.

Therapeutic benefits targeting B-cells in chronic graft-versus-host disease

Allogeneic hematopoietic cell transplantation (allo-HCT) can be a curative strategy for hematological diseases, and the indications for allo-HCT have broadened widely due to recent progress in supportive strategies. However, patients must overcome various complications and chronic graft-versus-host disease (cGVHD) remains the most common allo-HCT cause of long-term morbidity and mortality. cGVHD is difficult to biologically assess due to the heterogeneity of cGVHD symptoms, and the pathogenesis of cGVHD has yet to be established. Recent experimental model progressxa0has suggested that B-cells play a critical role in cGVHD development. Consistent with these experimental results, some clinical studies investigating B-cell depletion and modulation of B-cell signaling pathways have decreased cGVHD incidence and provided some therapeutic benefit. However, randomized control studies are necessary to confirm the efficacy of B-cell targeting drugs for cGVHD. Here, we review the pathophysiology of cGVHD, especially focusing on the role of B-cell immunity, and discuss the efficacy of both B-cell depletion and modulation of B-cell signaling pathways inxa0human cGVHD prevention, initial treatment, and salvage treatment.

Risks and benefits of sex-mismatched hematopoietic cell transplantation differ according to conditioning strategy

Sex-mismatched hematopoietic cell transplantation is linked to increased graft-versus-host disease and mortality in myeloablative conditioning. Here we evaluated outcomes of 1,041 adult transplant recipients at two centers between 2006 and 2013 and investigated how the effect of sex-mismatching differed in myeloablative, reduced-intensity, and non-myeloablative total lymphoid irradiation with anti-thymocyte globulin conditioning. Among patients who underwent myeloablative conditioning, male recipients with female donors had increased chronic graft-versus-host disease (hazard ratio 1.83, P<0.01), increased non-relapse mortality (hazard ratio 1.84, P=0.022) and inferior overall survival (hazard ratio 1.59, P=0.018). In contrast, among patients who received reduced-intensity conditioning, male recipients with female donors had increased acute graft-versus-host disease (hazard ratio 1.96, P<0.01) but no difference in non-relapse mortality or overall survival. Among the patients who underwent total lymphoid irradiation with anti-thymocyte globulin, male recipients with female donors showed no increase in graft-versus-host disease or non-relapse mortality. Notably, only in the cohort receiving total lymphoid irradiation with anti-thymocyte globulin were male recipients with female donors significantly associated with reduced relapse (hazard ratio 0.64, P<0.01), and allo-antibody responses against H-Y antigens were predictive of reduced relapse. In the cohort given total lymphoid irradiation with anti-thymocyte globulin, the graft-versus-leukemia effect resulted in superior overall survival in recipients of sex-mismatched grafts (HR 0.69, P=0.037). In addition, only in the cohort treated with total lymphoid irradiation with anti-thymocyte globulin were female recipients with male donors associated with reduced relapse (hazard ratio 0.59, P<0.01) and superior survival (hazard ratio 0.61, P=0.014) compared with sex-matched pairs. We conclude that the risks and benefits of sex-mismatched transplants appear to differ according to conditioning strategy and this could affect donor selection.

Presensitization to HY antigens in female donors prior to transplant is not associated with male recipient post-transplant HY antibody development nor with clinical outcomes.

It has been shown that chronic graft-versus-host disease (cGVHD) incidence is significantly increased in male recipients receiving allogeneic hematopoietic cell transplant from female donors (F→M HCT).1,2 B cell immunity plays a critical role in cGVHD development,3,4 and we have so far investigated clinically relevant immune responses against minor antigens encoded by the Y-chromosome (HY antigens) following F→M HCT.5–7 Recently, we have demonstrated that in F→M HCT, antibody responses against HY antigens (HY-Ab) are correlated with cGVHD and that the cumulative number of HY-Abs three months post-HCT could significantly predict cGVHD development and non-relapse mortality.8

Risk factors and prognosis of hepatic acute GvHD after allogeneic hematopoietic cell transplantation.

Hepatic acute GvHD (aGvHD) is associated with high mortality owing to poor response to immunosuppressive therapy. The pathogenesis of hepatic aGvHD differs from that of other lesions, and specific risk factors related to pre-transplant liver conditions should be determined. We conducted a cohort study by using a Japanese transplant registry database (N=8378). Of these subjects, 1.5% had hepatitis C virus Ab (HCV-Ab) and 9.4% had liver dysfunction (elevated transaminase or bilirubin levels) before hematopoietic cell transplantation (HCT). After HCT, the cumulative incidence of hepatic aGvHD was 6.7%. On multivariate analyses, HCV-Ab positivity (hazard ratio (HR), 1.93; P=0.02) and pre-transplant liver dysfunction (HR, 1.85; P<0.01), as well as advanced HCT risk, unrelated donors, HLA mismatch and cyclosporine as GvHD prophylaxis, were significant risk factors for hepatic aGvHD, whereas hepatitis B virus surface Ag was not. Hepatic aGvHD was a significant risk factor for low overall survival and high transplant-related mortality in all aGvHD grades (P<0.01). This study is the first to show the relationship between pre-transplant liver conditions and hepatic aGvHD. A prospective study is awaited to validate the results of this study and establish a new strategy especially for high-risk patients.

Upper gastrointestinal acute graft-versus-host disease adds minimal prognostic value in isolation or with other graft-versus-host disease symptoms as currently diagnosed and treated

Upper gastrointestinal acute graft-versus-host disease is reported in approximately 30% of hematopoietic stem cell transplant recipients developing acute graft-versus-host disease. Currently classified as Grade II in consensus criteria, upper gastrointestinal acute graft-versus-host disease is often treated with systemic immunosuppression. We reviewed the Center for International Blood and Marrow Transplant Research database to assess the prognostic implications of upper gastrointestinal acute graft-versus-host disease in isolation or with other acute graft-versus-host disease manifestations. 8567 adult recipients of myeloablative allogeneic hematopoietic stem cell transplant receiving T-cell replete grafts for acute leukemia, chronic myeloid leukemia or myelodysplastic syndrome between 2000 and 2012 were analyzed. 51% of transplants were from unrelated donors. Reported upper gastrointestinal acute graft-versus-host disease incidence was 12.1%; 2.7% of recipients had isolated upper gastrointestinal acute graft-versus-host disease, of whom 95% received systemic steroids. Patients with isolated upper gastrointestinal involvement had similar survival, disease-free survival, transplant-related mortality, and relapse as patients with Grades 0, I, or II acute graft-versus-host disease. Unrelated donor recipients with isolated upper gastrointestinal acute graft-versus-host disease had less subsequent chronic graft-versus-host disease than those with Grades I or II disease (P=0.016 and P=0.0004, respectively). Upper gastrointestinal involvement added no significant prognostic information when present in addition to other manifestations of Grades I or II acute graft-versus-host disease. If upper gastrointestinal symptoms were reclassified as Grade 0 or I, 425 of 2083 patients (20.4%) with Grade II disease would be downgraded, potentially impacting the interpretation of clinical trial outcomes. Defining upper gastrointestinal acute graft-versus-host disease as a Grade II entity, as it is currently diagnosed and treated, is not strongly supported by this analysis. The general approach to diagnosis, treatment and grading of upper gastrointestinal symptoms and their impact on subsequent acute graft-versus-host disease therapy warrants reevaluation.

High-throughput allogeneic antibody detection using protein microarrays.

Enzyme-linked immunosorbent assays (ELISAs) have traditionally been used to detect alloantibodies in patient plasma samples post hematopoietic cell transplantation (HCT); however, protein microarrays have the potential to be multiplexed, more sensitive, and higher throughput than ELISAs. Here, we describe the development of a novel and sensitive microarray method for detection of allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome, called HY antigens. Six microarray surfaces were tested for their ability to bind recombinant protein and peptide HY antigens. Significant allogeneic immune responses were determined in male patients with female donors by considering normal male donor responses as baseline. HY microarray results were also compared with our previous ELISA results. Our overall goal was to maximize antibody detection for both recombinant protein and peptide epitopes. For detection of HY antigens, the Epoxy (Schott) protein microarray surface was both most sensitive and reliable and has become the standard surface in our microarray platform.

Sensitization to HY-Antigen in Female Donors Was Not Associated with the Post-Transplant HY-IgG Development Nor Clinical Outcomes in Sex-Mismatched Transplantation

s / Biol Blood Marrow Transplant 20 (2014) S45eS56 S54 results suggest that post-transplant IL-22 administration represents a novel strategy to reduce gut GVHD by direct protection of intestinal epitheliumwithout limiting immune function post-transplant.