Rituximab prophylaxis prevents corticosteroid-requiring chronic GVHD after allogeneic peripheral blood stem cell transplantation: results of a phase 2 trial

Rituximab-based first-line treatment of cGVHD after allogeneic SCT: results of a phase 2 study

Chronic graft-versus-host disease (cGVHD) is the main cause of late nonrelapse mortality and morbidity after allogeneic stem cell transplantation (allo-SCT). To improve such patients' outcomes, we conducted a phase 2, prospective, multicenter trial to test the efficacy of the addition of rituximab to corticosteroids (CSs) and cyclosporine A (CsA) as first-line therapy for newly diagnosed cGVHD after allo-SCT. Twenty-four patients (median age, 47 years) with mild (n = 2), moderate (n = 7), or severe (n = 15) cGVHD were included. All patients received rituximab 375 mg/m² weekly for 4 weeks, followed by a second course 1 month later for patients with partial response. Twenty of 24 patients (83%) were in response at 1 year. Furthermore, among 19 evaluable patients, 14 (74%) were off CSs. The estimated 1-year overall survival was 83%, and the 1-year cumulative incidence of nonrelapse mortality was 14%. One patient died of progressive multifocal leukoencephalopathy. Although PD-L1^hi naive B cells were significantly decreased at diagnosis of cGVHD, they increased after anti-CD20 B-cell depletion. In contrast, activated ICOS^hi PD-1^hi circulating T follicular helper (Tfh) cells decreased after rituximab treatment. Overall, the addition of rituximab to corticosteroid and CsA appeared to be safe and effective for first-line treatment of cGVHD. Furthermore, our data suggest that this efficacy may be in part related to an effect on PD-L1^hi B cells and Tfh cells. This study was registered at www.clinicaltrials.gov as identifier NCT01135641.

Long-term outcome of Epstein-Barr virus DNAemia and PTLD with the use of preemptive rituximab following allogeneic HSCT

We studied retrospectively the outcome of Epstein-Barr virus (EBV)-related disease with EBV monitoring and preemptive rituximab to prevent post-transplant lymphoproliferative disorder (PTLD) in 319 consecutive allogeneic stem cell transplantations 2004-2012. Patients who received anti-thymocyte globulin (ATG) or alemtuzumab were regarded as high-risk for PTLD (n = 214). EBV DNAemia ≥1000 copies/mL plasma was observed in 50 (23%) of the high-risk patients. Thirty-three of the high-risk (15%) and one of the low-risk (1%) patients received rituximab, in combination with reduction of immunosuppression (n = 24) or chemotherapy (n = 4). Although rituximab was initiated only 5 d after first EBV load ≥1000 copies/mL, 85% of the rituximab-treated patients developed symptoms (lymphadenopathy 50%, fever 76%, and encephalitis/meningitis 12%). Response-rate to EBV treatment was 88%. Overall survival at 1- and 5-year was 71 and 52% for rituximab-treated patients, which was not inferior to all other patients post-transplant. In conclusion, rituximab therapy for EBV DNAemia does not affect long-term survival negatively.

A review of late complications of allogeneic hematopoietic stem cell transplantations

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective and curative treatment of different malignant and non-malignant diseases. Early transplant-related mortality after allo-HSCT has decreased with reduced-intensity conditioning regimens and effective anti-infectious treatments, but late transplant-related mortality is still a problem. Physicians are now paying more attention to late complications that may worsen the quality of life of many transplant recipients. Chronic graft versus host disease (cGVHD) is one of the major causes of late transplant-related mortality after allo-HSCT. This review discusses recent advances that have been made in clinical evaluation and treatment of late transplant-related complications including cGVHD. The different sites of involvement are organs, especially the skin and eye, and the gastrointestinal, endocrinologic, metabolic, renal, cardiologic, pulmonary, connective tissue, and neurological systems. In addition, this review includes infections and secondary malignancies in post-transplant settings that worsen quality of life in long-term follow-ups.

In vitro effects of different 8-methoxypsoralen treatment protocols for extracorporeal photopheresis on mononuclear cells

Extracorporeal photopheresis (ECP) is an important second-line therapy for graft-versus-host disease. A central therapeutic mechanism is the induction of immune tolerance through apoptosis in patient’s leukocytes, caused by ex vivo incubation with 8-methoxypsoralen (8-MOP) and subsequent UVA irradiation.

We hypothesized that different 8-MOP incubation times and an additional 8-MOP removal step could influence the apoptosis kinetics of leukocytes in general and in particular could lead to different apoptotic levels in the leukocyte subpopulations. After 8-MOP/UVA treatment of human leukocytes, cells were cultured and the percentage of annexin V positive cells from several leukocyte subpopulations was determined. Only regulatory T cells (Tregs) were relatively resistant to 8-MOP/UVA induced apoptosis. When cells were incubated for 30 minutes with 8-MOP prior to UVA exposure, higher percentages of annexin V positive cells were detected on day 1 and day 2 after treatment. Removal of 8-MOP after UVA exposure caused no significant changes in the apoptosis kinetics during the 72 h culture period compared with unwashed cells. The results of our in vitro study indicate that it could be possible to adjust the apoptosis kinetics via modulation of the 8-MOP incubation time. In further in vivo studies it should be elucidated to which extent different apoptosis kinetics influence the therapeutic effect of ECP since steady-state apoptosis levels are probably important for establishing a long lasting immune tolerance. Furthermore we found that Tregs, according to their well-known tolerogenic function, are more resistant to apoptosis after 8-MOP/UVA treatment compared to GvHD inducing T cell populations.

Rituximab-containing reduced-intensity conditioning improves progression-free survival following allogeneic transplantation in B cell non-Hodgkin lymphoma

Background

In B cell non-Hodgkin lymphoma (B-NHL), rituximab-containing reduced-intensity conditioning regimens (R-RIC) have been shown to provide favorable outcomes in single-arm studies; however, large multicenter studies comparing R-RIC and non-rituximab-containing reduced-intensity conditioning regimens (nonR-RIC) have not been performed. Using the CIBMTR database, we report the outcomes of R-RIC versus nonR-RIC regimens in B-NHL.

Methods

We evaluated 1401 adult B-NHL patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) who received nonR-RIC (n = 1022) or R-RIC (n = 379) regimens. Graft-versus-host disease (GVHD) prophylaxis was limited to calcineurin inhibitor-based approaches.

Results

Median follow-up of survivors in the R-RIC and nonR-RIC groups was 47 and 37 months, respectively. On multivariate analysis, no difference was seen between the R-RIC and nonR-RIC cohorts in terms of acute GVHD grade II–IV (RR = 1.14, 95%CI = 0.83–1.56, p = 0.43) or grade III–IV (RR = 1.16, 95%CI = 0.72–1.89, p = 0.54), chronic GVHD (RR = 1.15, 95%CI = 0.92–1.46, p = 0.22), non-relapse mortality (RR = 0.90; 95%CI = 0.67–1.22; p = 0.51), relapse/progression (RR = 0.79; 95%CI = 0.63–1.01; p = 0.055), and mortality (RR = 0.84, 95%CI = 0.69–1.02, p = 0.08) risk. However, R-RIC was associated with a significantly improved progression-free survival (RR = 0.76; 95%CI 0.62–0.92; p = 0.006). On subgroup analysis, mortality benefit was noted in the R-RIC group patients not receiving busulfan-based RIC (RR = 0.76; 95%CI = 0.60–0.96; p = 0.02) and with the use of a higher cumulative rituximab dose (RR = 0.43; 95%CI = 0.21–0.90; p = 0.02).

Conclusion

Our analysis shows that inclusion of rituximab in RIC regimens improves progression-free survival in patients with B cell NHL. These data supports the use of R-RIC in B-NHL patients undergoing allo-HCT.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0487-y) contains supplementary material, which is available to authorized users.

Allogeneic Stem Cell Transplantation for Relapsed/Refractory B Cell Lymphomas: Results of a Multicenter Phase II Prospective Trial including Rituximab in the Reduced-Intensity Conditioning Regimen

The treatment of patients with refractory/relapsed B cell non-Hodgkin lymphoma (NHL) is evolving because of the availability of novel drugs. Allogeneic stem cell transplantation (alloSCT) can be curative, but its morbidity and mortality remain a matter of concern. We conducted a multicenter prospective phase II trial to evaluate the benefit of including only 1 dose of rituximab in the conditioning regimen before alloSCT. The primary endpoint was progression-free survival. The study enrolled 121 patients with relapsed/refractory B cell lymphomas. The conditioning regimen consisted of thiotepa, cyclophosphamide, fludarabine, and rituximab (500 mg/m²). Rabbit antithymocyte globulin was administered only in case of unrelated donors. Sixty-seven (55%) and 54 (45%) patients received grafts from related and unrelated donors, respectively. The crude cumulative incidence (CCI) of nonrelapse mortality (NRM) was 21% at 3 years. The CCIs of chronic graft-verus-host disease (GVHD) at 3 years were 54% and 31% in recipients of matched sibling and unrelated grafts, respectively. At a median follow-up of 41 months, the estimated 3-year progression-free and overall survival were 50% and 61%, respectively. Long-term outcome was also evaluated with the composite endpoint of GVHD-free and relapse-free survival (GRFS). This is the first work evaluating the GRFS in a prospective trial of lymphoma patients: the 1-year and 3-year GRFS were 40% and 34%, respectively. AlloSCT can cure a fraction of patients with rather low NRM and an encouraging PFS and GRFS.

Protective Effect of Rituximab in Chronic Graft-Versus-Host Disease Occurrence in Allogeneic Transplant patients with Epstein Barr Virus Viremia

B cells are involved in chronic graft-versus-host disease (cGVHD) pathogenesis, and Rituximab may have a therapeutic effect on cGVHD in allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients. Herein, we retrospectively evaluated the prophylactic effect of Rituximab on cGVHD in a group of Chinese allo-HSCT patients. A total of 102 patients, who suffered Epstein Barr virus (EBV) viremia within 100 days after allo-HSCT, were included in this study. Fifty patients received Rituximab (375 mg/m² weekly) for EBV viremia, while fifty-two patients did not receive Rituximab. A competing risk model was adopted to compare cumulative incidence of cGVHD, cumulative incidence of relapse (CIR) and transplantation-related mortality (TRM) between two groups. Cumulative incidence of cGVHD in the Rituximab group was lower than in controls (P = 0.0579). Multivariate analyses confirmed that Rituximab was an independent factor for the reduction of cumulative cGVHD incidence (P = 0.0069). No significant difference was observed in CIR (P = 0.39) or TRM (P = 0.48) between two groups and 2-year OS and DFS were comparable (OS, P = 0.667; DFS, P = 0.571). Administration of Rituximab in the early post-transplantation phase may protect against cGVHD in allo-HSCT patients without increasing CIR or TRM.

The Biology of Chronic Graft-versus-Host Disease: A Task Force Report from the National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (GVHD) is the leading cause of late, nonrelapse mortality and disability in allogeneic hematopoietic cell transplantation recipients and a major obstacle to improving outcomes. The biology of chronic GVHD remains enigmatic, but understanding the underpinnings of the immunologic mechanisms responsible for the initiation and progression of disease is fundamental to developing effective prevention and treatment strategies. The goals of this task force review are as follows: This document is intended as a review of our understanding of chronic GVHD biology and therapies resulting from preclinical studies, and as a platform for developing innovative clinical strategies to prevent and treat chronic GVHD.

Novel targets in the treatment of chronic graft-versus-host disease

Despite advances that have improved survival after allogeneic hematopoietic stem cell transplantation (HCT), chronic graft-versus-host disease (GVHD) remains a leading cause of late morbidity and mortality after transplant. Current treatment options show limited efficacy in steroid-refractory disease, and there exists a paucity of robust data to guide management decisions. Lack of United States Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved agents in GVHD underscore the importance of developing novel therapies. Better understanding of the biology of chronic GVHD has provided novel targets for treatment, and structured guidelines in diagnosis and in clinical trial design have provided a common language and pathways for research in this area. These, combined with the surge of drug development in Oncology and Immunology, are factors that have contributed to the accelerating field of drug development and clinical research in chronic GVHD. In these exciting times, it is possible to foresee long awaited advances in the treatment of this devastating complication of HCT. This review will summarize the ongoing clinical development for novel therapies in chronic GVHD.

Mechanistic approaches for the prevention and treatment of chronic GVHD

Clinical outcomes for patients undergoing allogeneic hematopoietic stem cell transplantation continue to improve, but chronic graft-versus-host disease (GVHD) remains a common toxicity and major cause of nonrelapse morbidity and mortality. Treatment of chronic GVHD has previously relied primarily on corticosteroids and other broadly immune suppressive agents. However, conventional immune suppressive agents have limited clinical efficacy in chronic GVHD, and prolonged immune suppressive treatments result in additional toxicities that further limit clinical recovery from transplant and return to normal daily function. Recent advances in our understanding of the immune pathology of chronic GVHD offer the possibility that new therapeutic approaches can be directed in more precise ways to target specific immunologic mechanisms and pathways. In this review, we briefly summarize current standard treatment options and present new therapeutic approaches that are supported by preclinical studies and early-phase clinical trials suggesting that these approaches may have clinical utility for treatment or prevention of chronic GVHD. Further evaluation of these new therapeutic options in well-designed prospective multicenter trials are needed to identify the most effective new agents and improve outcomes for patients with chronic GVHD.

Chronic graft-versus-host disease: biological insights from preclinical and clinical studies

With the increasing use of mismatched, unrelated, and granulocyte colony-stimulating factor-mobilized peripheral blood stem cell donor grafts and successful treatment of older recipients, chronic graft-versus-host disease (cGVHD) has emerged as the major cause of nonrelapse mortality and morbidity. cGVHD is characterized by lichenoid changes and fibrosis that affects a multitude of tissues, compromising organ function. Beyond steroids, effective treatment options are limited. Thus, new strategies to both prevent and treat disease are urgently required. Over the last 5 years, our understanding of cGVHD pathogenesis and basic biology, born out of a combination of mouse models and correlative clinical studies, has radically improved. We now understand that cGVHD is initiated by naive T cells, differentiating predominantly within highly inflammatory T-helper 17/T-cytotoxic 17 and T-follicular helper paradigms with consequent thymic damage and impaired donor antigen presentation in the periphery. This leads to aberrant T- and B-cell activation and differentiation, which cooperate to generate antibody-secreting cells that cause the deposition of antibodies to polymorphic recipient antigens (ie, alloantibody) or nonpolymorphic antigens common to both recipient and donor (ie, autoantibody). It is now clear that alloantibody can, in concert with colony-stimulating factor 1 (CSF-1)-dependent donor macrophages, induce a transforming growth factor β-high environment locally within target tissue that results in scleroderma and bronchiolitis obliterans, diagnostic features of cGVHD. These findings have yielded a raft of potential new therapeutics, centered on naive T-cell depletion, interleukin-17/21 inhibition, kinase inhibition, regulatory T-cell restoration, and CSF-1 inhibition. This new understanding of cGVHD finally gives hope that effective therapies are imminent for this devastating transplant complication.

Reduced-Intensity Conditioning with Fludarabine, Cyclophosphamide, and Rituximab Is Associated with Improved Outcomes Compared with Fludarabine and Busulfan after Allogeneic Stem Cell Transplantation for B Cell Malignancies

Reduced-intensity conditioning (RIC) has been used increasingly for allogeneic hematopoietic cell transplantation to minimize transplant-related mortality while maintaining the graft-versus-tumor effect. In B cell lymphoid malignancies, reduced-intensity regimens containing rituximab, an antiCD20 antibody, have been associated with favorable survival; however, the long-term outcomes of rituximab-containing versus nonrituximab-containing regimens for allogeneic hematopoietic cell transplantation in B cell lymphoid malignancies remain to be determined. We retrospectively analyzed 94 patients who received an allogeneic transplant for a B cell lymphoid malignancy. Of these, 33 received RIC with fludarabine, cyclophosphamide, and rituximab (FCR) and graft-versus-host disease (GVHD) prophylaxis with a calcineurin inhibitor and mini-methotrexate, and 61 received RIC with fludarabine and busulfan (FluBu) and GVHD prophylaxis with a calcineurin inhibitor and mycophenolate mofetil. The 2-year overall survival was superior in patients who received FCR versus FluBu (72.7% versus 54.1%, P = .031), and in multivariable analysis adjusted for Disease Risk Index and donor type, only the conditioning regimen (FluBu versus FCR: HR, 2.06; 95% CI, 1.04 to 4.08; P = .037) and Disease Risk Index (low versus intermediate/high: HR, .38; 95% CI, .17 to .86; P = .02) were independent predictors of overall survival. The 2-year cumulative incidence of chronic GVHD was lower in patients who received FCR versus FluBu (24.2% versus 51.7%, P = .01). There was no difference in rate of relapse/progression or acute GVHD. Our results demonstrate that the use of RIC with FCR and GVHD prophylaxis with a calcineurin inhibitor and mini-methotrexate is associated with decreased chronic GVHD and improved overall survival.

Reduced-Intensity Conditioning with Fludarabine, Cyclophosphamide, and High-Dose Rituximab for Allogeneic Hematopoietic Cell Transplantation for Follicular Lymphoma: A Phase Two Multicenter Trial from the Blood and Marrow Transplant Clinical Trials Network

Allogeneic (allo) hematopoietic cell transplantation (HCT) can induce long-term remissions in chemosensitive relapsed follicular lymphoma (FL). The Blood and Marrow Transplant Clinical Trials Network conducted a multicenter phase 2 trial to examine the efficacy of alloHCT using reduced-intensity conditioning with rituximab (RTX) in multiply relapsed, chemosensitive FL. The primary endpoint was 2-year progression-free survival (PFS). The conditioning regimen consisted of fludarabine, cyclophosphamide, and high-dose RTX (FCR), in which 3 of the 4 doses of RTX were administered at a dose of 1 gm/m(2). Graft-versus-host disease (GVHD) prophylaxis was with tacrolimus and methotrexate. Sixty-five patients were enrolled and 62 were evaluable. Median age was 55 years (range, 29 to 74). This group was heavily pretreated: 77% had received ≥ 3 prior regimens, 32% had received ≥ 5 prior regimens, and 11% had received prior autologous HCT. Donors were HLA-matched siblings (n = 33) or HLA-matched unrelated adults (n = 29). No graft failures occurred. The overall response rate after HCT was 94% with 90% in complete remission (CR), including 24 patients not in CR before alloHCT. With a median follow-up of 47 months (range, 30 to 73), 3-year PFS and overall survival rates were 71% (95% confidence interval, 58% to 81%) and 82% (95% confidence interval, 70% to 90%), respectively. Three-year cumulative incidences of relapse/progression and nonrelapse mortality were 13% and 16%, respectively. Two-year cumulative incidences of grades 2 to 4 and grades 3 or 4 acute GVHD were 27% and 10%, respectively, and extensive chronic GVHD incidence was 55%. Serum RTX concentrations peaked at day +28 and remained detectable as late as 1 year in 59% of patients with available data. In conclusion, alloHCT with FCR conditioning confers high CR rates, a low incidence of relapse/progression, and excellent survival probabilities in heavily pretreated FL patients.

Impact of Donor Epstein-Barr Virus Serostatus on the Incidence of Graft-Versus-Host Disease in Patients With Acute Leukemia After Hematopoietic Stem-Cell Transplantation: A Study From the Acute Leukemia and Infectious Diseases Working Parties of the European Society for Blood and Marrow Transplantation

PURPOSE

We investigated the effect of Epstein-Barr virus (EBV) serostatus on the overall outcome of allogeneic hematopoietic stem-cell transplantation (allo-HSCT).

PATIENTS AND METHODS

The study included 11,364 patients who underwent allogeneic peripheral-blood or bone marrow transplantation for acute leukemia between 1997 and 2012. We analyzed the impact of donor and recipient EBV serologic status on overall survival, relapse-free survival, relapse incidence, nonrelapse mortality, and incidence of graft-versus-host disease (GVHD) after allo-HSCT.

RESULTS

Patients receiving grafts from EBV-seropositive donors had the same overall survival as patients who received grafts from EBV-seronegative donors (hazard ratio [HR], 1.05; 95% CI, 0.97 to 1.12; P = .23). Seropositive donors also had no influence on relapse-free survival (HR, 1.04; 95% CI, 0.97 to 1.11; P = 0.31), relapse incidence (HR, 1.03; 95% CI, 0.94 to 1.12; P = .58), and nonrelapse mortality (HR, 1.05; 95% CI, 0.94 to 1.17; P = .37). However, in univariate analysis, recipients receiving grafts from seropositive donors had a higher risk of chronic GVHD than those with seronegative donors (40.8% v 31.0%, respectively; P < .001; HR, 1.42; 95% CI, 1.30 to 1.56). When adjusting for confounders, higher risk was identified for both acute and chronic GVHD. In seronegative patients with seropositive donors, the HR for chronic GVHD was 1.30 (95% CI, 1.06 to 1.59; P = .039). In seropositive patients with seropositive donors, the HR was 1.24 (95% CI, 1.07 to 1.45; P = .016) for acute GVHD and 1.43 (95% CI, 1.23 to 1.67; P < .001) for chronic GVHD. Seropositive patients with seronegative donors did not have an increased risk of GVHD.

CONCLUSION

Our data suggest that donor EBV status significantly influences development of acute and chronic GVHD after allo-HSCT.

Emerging drugs for graft-versus-host disease

INTRODUCTION

Graft-versus-host disease (GVHD) leads to significant morbidity and mortality after allogeneic stem cell transplantation. While corticosteroids alone are adequate in some cases, they are often insufficient, leading to poor quality of life associated with the symptoms of disease, or mortality from infection and GVHD. Moreover, corticosteroids have significant side effects and often do not lead to durable responses. New therapies are needed to improve the development and progression of acute and chronic GVHD.

AREAS COVERED

We discuss the spectrum of emerging drugs for GVHD prevention and therapy. Cellular therapies will be briefly discussed. The available pre-clinical and clinical data regarding monoclonal antibodies, interleukin-2, alpha-1 antitrypsin, histone deacetylase inhibitors, tyrosine kinase inhibitors, and proteasome inhibitors will be reviewed.

EXPERT OPINION

Although therapies emerging for GVHD remain promising, most of these drugs are still in early phase clinical trials and require randomized comparisons before formal conclusions can be drawn. It is likely that in the near future some of these agents will show improvements in response when compared with corticosteroids alone. Although it is difficult to predict which of these agents will be most promising, alpha-1 antitrypsin, ruxolitinib and interleukin-2 have demonstrated encouraging results.

Risk of graft-versus-host disease with rituximab-containing conditioning regimens in allogeneic hematopoietic stem cell transplant

Graft-versus-host disease represents a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant patients. There is growing evidence that B lymphocytes may play a role in the pathogenesis of acute graft-versus-host disease. The purpose of this retrospective cohort study was to evaluate the efficacy of rituximab-containing conditioning regimens in decreasing graft-versus-host disease in allogeneic hematopoietic stem cell transplant patients who received standardized tacrolimus-based graft-versus-host disease prophylaxis regimens. Patients were divided into two cohorts, based on the presence (RTX, n = 54) or absence (No-RTX, n = 105) of rituximab in the conditioning regimen and were matched 1:2 for major graft-versus-host disease risk factors. The incidence of grade II-IV acute graft-versus-host disease was not different between the two groups (37% vs. 26%, p = 0.147). When restricting the analysis to recipients of peripheral blood hematopoietic stem cell transplants, the RTX group had a higher incidence of grade II-IV acute graft-versus-host disease, relapse, or death prior to day 100 (55% vs. 36%, p = 0.037). The median time to the onset of acute graft-versus-host disease was no different between the RTX and No-RTX groups (67 vs. 74 days, respectively, p = 0.141). Inhibition of antigen presentation by B cells with rituximab-based conditioning regimens does not appear to reduce the incidence of acute graft-versus-host disease in allogeneic hematopoietic stem cell transplant recipients.

Circulating T follicular helper cells with increased function during chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) remains a major late complication of allogeneic hematopoietic stem cell transplantation (HSCT). Previous studies have established that both donor B and T cells contribute to immune pathology in cGVHD but the mechanisms responsible for coordinated B- and T-cell responses directed against recipient antigens have not been understood. T follicular helper cells (TFH) play an important role in the regulation of B-cell immunity. We performed extensive phenotypic and functional analysis of circulating TFH (cTFH) and B cells in 66 patients after HSCT. Patients with active cGVHD had a significantly lower frequency of cTFH compared with patients without cGVHD. This was associated with higher CXCL13 plasma levels suggesting increased homing of TFH to secondary lymphoid organs. In patients with active cGVHD, cTFH phenotype was skewed toward a highly activated profile with predominance of T helper 2 (Th2)/Th17 subsets. Activated cTFH in patients with cGVHD demonstrated increased functional ability to promote B-cell immunoglobulin secretion and maturation. Moreover, the activation signature of cTFH was highly correlated with increased B-cell activation and plasmablast maturation in patients after transplant. These studies provide new insights into the immune pathogenesis of human cGVHD and identify TFH as a key coordinating element supporting B-cell involvement in this disease.

Potential of glycosylation research in graft versus host disease after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Glycans, complex oligosaccharides, are directly involved in almost every biological process, have a fundamental role in the immune system, and are probably involved in nearly every human disease. However, glycosylation has been greatly ignored in the area of allogeneic hematopoietic stem cell transplantation (alloHSCT) and graft versus host disease (GVHD). Both acute and chronic GVHD are multisystemic debilitating immunological disturbances arising after alloHSCT.

SCOPE OF REVIEW

In this paper, we review the glycosylation research already done in the field of alloHSCT and GVHD and evaluate further potential of glycan analysis in GVHD by looking into resembling inflammatory and autoimmune conditions.

MAJOR CONCLUSIONS

Glycan research could bring significant improvement in alloHSCT procedure with reduction in following complications, such as GVHD. Identifying glycan patterns that induce self-tolerance and the ones that cause the auto- and allo-immune response could lead to innovative and tissue-specific immunomodulative therapy instead of the current immunosuppressive treatment, enabling preservation of the graft-versus-tumor effect. Moreover, improved glycan pattern analyses could offer a more complete assessment and greatly needed dynamic biomarkers for GVHD.

GENERAL SIGNIFICANCE

This review is written with a goal to encourage glycan research in the field of alloHSCT and GVHD as a perspective tool leading to improved engraftment, discovery of much needed biomarkers for GVHD, enabling an appropriate therapy and improved monitoring of therapeutic response. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Approaches for the prevention of graft-versus-host disease following hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) is an important therapeutic option for malignant and non-malignant diseases, but the more widespread application of the therapy remains limited by the occurrence of graft versus host disease (GVHD). GVHD results from immune-mediated injury by donor immune cells against tissues in the HCT recipient, and can be characterized as acute or chronic depending on the time of onset and site of organ involvement. The majority of efforts have focused on GVHD prevention. Calcineurin inhibitors are the most widely used agents and are included in almost all regimens. Despite current prophylaxis strategies, 40-70% of patients remain at risk for developing GVHD. Herein, we review standard and emerging therapies used in GVHD management.

Phase II Study of Nonmyeloablative Allogeneic Bone Marrow Transplantation for B Cell Lymphoma with Post-Transplantation Rituximab and Donor Selection Based First on Non-HLA Factors

Outcomes of nonmyeloablative (NMA), HLA-haploidentical (haplo), related-donor allogeneic blood or marrow transplantation (allo-BMT) with high-dose post-transplantation cyclophosphamide (PTCy) appear to be similar to those using HLA-matched donors. Thus, it may be possible to prioritize donor factors other than HLA matching that could enhance antitumor activity. The Fc receptor polymorphism FCGR3A-158VV may confer greater sensitivity to rituximab than FCGR3A-158FF. In a prospective phase II study of NMA, related-donor allo-BMT with PTCy and post-transplantation rituximab for patients with B cell lymphomas, we hypothesized that donor selection that prioritized FCGR3A-158 polymorphism over HLA matching would be feasible, safe, and improve outcomes. The primary endpoint was 1-year progression-free survival (PFS). Of 83 patients transplanted (median age, 59 years), 69 (83%) received haplo grafts. Fifty-four (65%) received a graft that maintained or improved their Fc receptor polymorphism status. With 2.6-year median follow-up, the 1-year PFS and overall survival (OS) probabilities were 71% and 86%, respectively, with 1-year relapse and nonrelapse mortality (NRM) probabilities of 20% and 8%. At 1 year, the probability of acute grades II to IV graft-versus-host disease (GVHD) was 41%, with acute grades III to IV GVHD probability of 5% and chronic GVHD probability of 11%. Among haplo transplants, the 1-year probabilities of PFS, OS, relapse, and NRM were 70%, 83%, 20%, and 10%, respectively. No differences in outcomes were observed based on donor FCGR3A-158 polymorphism. Excess infection risk was not apparent with post-transplantation rituximab. Although donor selection based on FCGR3A-158 polymorphism was not shown to influence PFS, this study suggests that donor selection based on criteria other than best HLA match is feasible and safe. This study opens the way for the future investigation of donor prioritization based on promising non-HLA factors that may improve antitumor activity and decrease relapse after allo-BMT. This study was registered at www.clinicaltrials.gov as NCT00946023.

Reprint of: B cells in chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) continues to be a common complication of allogeneic hematopoietic stem cell transplantation. Unlike acute graft-versus-host disease, which is mediated almost entirely by donor T cells, the immune pathology of cGVHD is more complex and donor B cells have also been found to play an important role. Recent studies from several laboratories have enhanced our understanding of how donor B cells contribute to this clinical syndrome and this has led to new therapeutic opportunities. Here, Dr Sarantopoulos reviews some of the important mechanisms responsible for persistent B cell activation and loss of B cell tolerance in patients with cGVHD. Dr Blazar describes recent studies in preclinical models that have identified novel B cell-directed agents that may be effective for prevention or treatment of cGVHD. Some B cell-directed therapies have already been tested in patients with cGVHD and Dr Cutler reviews the results of these studies documenting the potential efficacy of this approach. Supported by mechanistic studies in patients and preclinical models, new B cell-directed therapies for cGVHD will now be evaluated in clinical trials.

Targeting Syk-activated B cells in murine and human chronic graft-versus-host disease

Novel therapies for chronic graft-versus-host disease (cGVHD) are needed. Aberrant B-cell activation has been demonstrated in mice and humans with cGVHD. Having previously found that human cGVHD B cells are activated and primed for survival, we sought to further evaluate the role of the spleen tyrosine kinase (Syk) in cGVHD in multiple murine models and human peripheral blood cells. In a murine model of multiorgan system, nonsclerodermatous disease with bronchiolitis obliterans where cGVHD is dependent on antibody and germinal center (GC) B cells, we found that activation of Syk was necessary in donor B cells, but not T cells, for disease progression. Bone marrow-specific Syk deletion in vivo was effective in treating established cGVHD, as was a small-molecule inhibitor of Syk, fostamatinib, which normalized GC formation and decreased activated CD80/86(+) dendritic cells. In multiple distinct models of sclerodermatous cGVHD, clinical and pathological disease manifestations were not eliminated when mice were therapeutically treated with fostamatinib, though both clinical and immunologic effects could be observed in one of these scleroderma models. We further demonstrated that Syk inhibition was effective at inducing apoptosis of human cGVHD B cells. Together, these data demonstrate a therapeutic potential of targeting B-cell Syk signaling in cGVHD.

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 progress has 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 in human cGVHD prevention, initial treatment, and salvage treatment.

Advances and challenges in immunotherapy for solid organ and hematopoietic stem cell transplantation

Although major advances have been made in solid organ and hematopoietic stem cell transplantation in the last 50 years, big challenges remain. This review outlines the current immunological limitations for hematopoietic stem cell and solid organ transplantation and discusses new immune-modulating therapies in preclinical development and in clinical trials that may allow these obstacles to be overcome.

Preferential depletion of host over donor T cells through in vivo decay of active rabbit-anti-thymocyte globulin levels during reduced intensity conditioning

Inadequate T-cell chimerism following reduced-intensity conditioning transplantation may contribute to graft rejection and disease relapse. Anti-thymocyte globulin (ATG) enhances early donor T-cell chimerism, but may also deplete donor T cells, increasing risks of infection and relapse. We prospectively tested administration of rabbit ATG (rATG) ⩾14 days before the infusion of the graft, followed by in vivo decay of active rATG levels, to selectively deplete host T cells. Twenty-three patients received rATG total dose 4.5 mg/kg on days -16 and -15, fludarabine 30 mg/m(2) per day on day -7 through -3, IV busulfan 130 mg/m(2) per day on days -4 and -3 and cyclophosphamide 1500 mg/m(2) on day -2. rATG levels were therapeutic in all patients on day -14, but were sub-therapeutic (<1 μg/mL) by day 0 in 82% of patients. Median donor T-cell chimerisms on days 30 and 180 were 100% (75-100%) and 100% (90-100%), respectively. Non-relapse mortality and relapse/progression at 48 months were 17 and 30%. Cumulative incidences of acute GvHD grades II-IV and III-IV were 39 and 9%. Median follow-up is 64 months (46-79 months). Survival and disease-free survival at 48 months were 70 and 52%. These data suggest that selective depletion of host T cells using this regimen is a feasible and effective strategy.

Ofatumumab in combination with glucocorticoids for primary therapy of chronic graft-versus-host disease: phase I trial results

Standard primary therapy for chronic graft-versus-host disease (GVHD) is incompletely effective. Based on biologic insights implicating pathogenic B cells, we conducted a phase I trial examining the combination of standard (1 mg/kg/day prednisone) glucocorticoid therapy with ofatumumab, a humanized anti-CD20 monoclonal antibody, for primary chronic GVHD therapy. Patients ages ≥ 18 with National Institutes of Health Consensus moderate-to-severe chronic GVHD newly requiring 1 mg/kg/day prednisone were treated at 3 escalating dose levels (300 mg, 700 mg, and 1000 mg) of i.v. ofatumumab on days 1 and 14 of initial glucocorticoid therapy. Dose-limiting toxicity (DLT) was defined by grade 4 infusion reactions, related grade 4 constitutional symptoms, related grade ≥ 3 organ toxicities, or grade 4 neutropenia lasting > 14 days. A total of 12 patients (median age 54; range, 25 to 72) were treated (dose level 1: n = 3; level 2: n = 3; level 3: n = 6). At enrollment, overall chronic GVHD was moderate (n = 7) or severe (n = 5), with diverse organ involvement (skin: n = 8; mouth: n = 8; eye: n = 8; lung: n = 4; gastrointestinal: n = 3; liver: n = 5; genital: n = 2; joint/fascia: n = 5). Infusion of ofatumumab was well tolerated, and no DLT was observed. From the total number of adverse events (n = 29), possibly related adverse events (n = 4) included grade 1 fatigue, grade 1 transaminitis, and 2 infusion reactions (grades 2 and 3). Infectious complications were expected, and there were no cases of hepatitis B reactivation or progressive multifocal leukoencephalopathy. Ofatumumab in combination with prednisone is safe and a phase II examination of efficacy is ongoing.

Allogeneic HY antibodies detected 3 months after female-to-male HCT predict chronic GVHD and nonrelapse mortality in humans

Allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome (HY-Abs) develop after hematopoietic cell transplant (HCT) of male recipients with female donors (F→M). However, the temporal association between HY-Ab development and chronic graft-versus-host disease (cGVHD) has yet to be elucidated. We studied 136 adult F→M HCT patients, with plasma prospectively collected through 3 years posttransplant, and measured immunoglobulin G against 6 H-Y antigens. Multiple HY-Abs were frequently detected beginning at 3 months posttransplant: 78 (57%) of F→M patients were seropositive for at least 1 of the 6 HY-Abs, and 3-month seropositivity for each HY-Ab was associated with a persistent seropositive response throughout the posttransplant follow-up period (P < .001 in each). There were no associations between pretransplant features and 3-month overall HY-Ab development. Detection of multiple HY-Abs at 3 months (represented by HY score) was significantly associated with an increased risk of cGVHD (P < .0001) and nonrelapse mortality (P < .01). Compared to clinical factors alone, the addition of HY score to clinical factors improved the predictive potential of cGVHD (P < .01). Monitoring HY-Ab development thus stratifies cGVHD risk in F→M HCT patients and may support preemptive prophylaxis therapy for cGVHD beginning at 3 months posttransplant.

Aberrant B-cell homeostasis in chronic GVHD

Recent studies have compelled further interest in the potential pathological role of B cells in chronic graft-versus-host disease (cGVHD). In patients with cGVHD, B cells are activated and primed for survival via B-cell activating factor and B-cell receptor-associated pathways. Understanding the signaling pathways that drive immune pathology in cGVHD will facilitate the development of new strategies to selectively target aberrantly activated B cells and restore normal B-cell homeostasis after allogeneic stem cell transplantation.

CD24(hi)CD27⁺ and plasmablast-like regulatory B cells in human chronic graft-versus-host disease

Interleukin 10 (IL-10)-producing B cells (regulatory B cells [Bregs]) regulate autoimmunity in mice and humans, and a regulatory role of IL-10-producing plasma cells has been described in mice. Dysfunction of B cells that maintain homeostasis may play a role in the pathogenesis of chronic graft-versus-host disease (cGVHD) after allogeneic stem cell transplantation. Here, we found a relation between decreased Breg frequencies and cGVHD severity. An impaired ability of B cells to produce IL-10, possibly linked to poor signal transducer and activator of transcription 3 and extracellular signal-regulated kinase phosphorylation, was found in patients with active cGVHD. IL-10 production was not confined to a single B-cell subset, but enriched in both the CD24(hi)CD27(+) and CD27(hi)CD38(hi) plasmablast B-cell compartments. In vitro plasmablast differentiation increased the frequency of IL-10-producing B cells. We confirmed that allogeneic transplant recipients had an impaired reconstitution of the memory B-cell pool. cGVHD patients had less CD24(hi)CD27(+) B cells and IL-10-producing CD24(hi)CD27(+) B cells. Patients with cGVHD had increased plasmablast frequencies but decreased IL-10-producing plasmablasts. These results suggest a role of CD24(hi)CD27(+) B-cell and plasmablast-derived IL-10 in the regulation of human cGVHD.

Graft-versus-host disease versus graft-versus-leukemia

Graft-versus-host disease (GVHD) is a significant clinical problem after allogenic hematopoietic cell transplantation (HCT) associated with substantial morbidity and mortality that limits the potential utility of transplantation. Associated with GVHD is the well-recognized phenomenon of the graft-versus-leukemia (GVL) effect that results in reduced risk of disease relapse. GVL effects have been observed after treatment for a broad range of hematological malignancies. Both GVHD and GVL are the results of T cell-effector functions that frames a major question in the field of how linked are these two phenomena. A major goal of basic science and translational research has been to develop strategies to reduce the risk of GVHD while maintaining or enhancing GVL. In this review, a number of different strategies developed from preclinical animal models will be explored with a focus on those approaches that have been extended to the clinic in an attempt to achieve this goal. Needless to say, there is no proven strategy; however, with the use of modern technology and clinical translation, there has been substantial progress toward this goal of reducing the risks of GVHD while promoting and enhancing GVL responses.

B cells in chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) continues to be a common complication of allogeneic hematopoietic stem cell transplantation. Unlike acute graft-versus-host disease, which is mediated almost entirely by donor T cells, the immune pathology of cGVHD is more complex and donor B cells have also been found to play an important role. Recent studies from several laboratories have enhanced our understanding of how donor B cells contribute to this clinical syndrome and this has led to new therapeutic opportunities. Here, Dr Sarantopoulos reviews some of the important mechanisms responsible for persistent B cell activation and loss of B cell tolerance in patients with cGVHD. Dr Blazar describes recent studies in preclinical models that have identified novel B cell-directed agents that may be effective for prevention or treatment of cGVHD. Some B cell-directed therapies have already been tested in patients with cGVHD and Dr Cutler reviews the results of these studies documenting the potential efficacy of this approach. Supported by mechanistic studies in patients and preclinical models, new B cell-directed therapies for cGVHD will now be evaluated in clinical trials.

Managing high-risk CLL during transition to a new treatment era: stem cell transplantation or novel agents?

Allogeneic hematopoietic stem cell transplantation (HSCT) has been considered as the treatment of choice for patients with high-risk chronic lymphocytic leukemia (HR-CLL; ie, refractory to purine analogs, short response [<24 months] to chemoimmunotherapy, and/or presence of del[17p]/TP53 mutations). Currently, treatment algorithms for HR-CLL are being challenged by the introduction of novel classes of drugs. Among them, BCR signal inhibitors (BCRi) and B-cell lymphoma 2 antagonists (BCL2a) appear particularly promising. As a result of the growing body of favorable outcome data reported for BCRi/BCL2a, uncertainty is emerging on how to advise patients with HR-CLL about indication for and timing of HSCT. This article provides an overview of currently available evidence and theoretical considerations to guide this difficult decision process. Until the risks and benefits of different treatment strategies are settled, all patients with HR-CLL should be considered for treatment with BCRi/BCL2a. For patients who respond to these agents, there are 2 treatment possibilities: (1) performing an HSCT or (2) continuing treatment with the novel drug. Individual disease-specific and transplant-related risk factors, along with patient's preferences, should be taken into account when recommending one of these treatments over the other.

Inhibition of protein geranylgeranylation specifically interferes with CD40-dependent B cell activation, resulting in a reduced capacity to induce T cell immunity

Ab-independent effector functions of B cells, such as Ag presentation and cytokine production, have been shown to play an important role in a variety of immune-mediated conditions such as autoimmune diseases, transplant rejection, and graft-versus-host disease. Most current immunosuppressive treatments target T cells, are relatively unspecific, and result in profound immunosuppression that places patients at an increased risk of developing severe infections and cancer. Therapeutic strategies, which interfere with B cell activation, could therefore be a useful addition to the current immunosuppressive armamentarium. Using a transcriptomic approach, we identified upregulation of genes that belong to the mevalonate pathway as a key molecular event following CD40-mediated activation of B cells. Inhibition of 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme of the mevalonate pathway, by lipophilic statins such as simvastatin and atorvastatin resulted in a specific inhibition of B cell activation via CD40 and impaired their ability to act as stimulatory APCs for allospecific T cells. Mechanistically, the inhibitory effect resulted from the inhibition of protein geranylgeranylation subsequent to the depletion of mevalonate, the metabolic precursor for geranylgeranyl. Thus, inhibition of geranylgeranylation either directly through geranylgeranyl transferase inhibitors or indirectly through statins represents a promising therapeutic approach for the treatment of diseases in which Ag presentation by B cells plays a role.

Low-dose antithymocyte globulin enhanced the efficacy of tacrolimus and mycophenolate for GVHD prophylaxis in recipients of unrelated SCT

We performed a retrospective analysis of the outcome of 197 consecutive unrelated donor transplant recipients who received GVHD prophylaxis either TM regimen (tacrolimus and mycophenolate) (121 patients) or TM/ATG-G regimen (TM with low-dose antithymocyte globulin (ATG) of 4.5 mg/kg, ATG-G, Genzyme) (76 patients). Cumulative incidences of grade II-IV acute GVHD for the TM and TM/ATG-G cohorts were 49% and 61% (P=0.11) and grade III-IV acute GVHD for the TM and TM/ATG-G cohorts were 27% and 14% (P=0.02), respectively. There was no difference in the incidence of relapse or disease progression between TM and TM/ATG-G-16% and 23% (P=0.64). TM/ATG-G cohort had lower incidence of non-relapse mortality (NRM; 37% vs 20%, P=0.01), chronic GVHD (56% vs 43%, P<0.001) and more favorable global chronic GVHD severity (P<0.001). Univariate analyses showed improved OS and PFS of patients who received TM/ATG-G. Multivariate analysis confirmed TM/ATG-G had a favorable influence on OS (P=0.05) but not on PFS (P=0.07). We concluded that low-dose ATG of 4.5 mg/kg given in conjunction with TM improved GVHD prophylaxis without increased risk of relapse. Lower NRM, lower incidence and severity of chronic GVHD could potentially improve survival.

Recent advances on cellular therapies and immune modulators for graft-versus-host disease

The efficacy of allogeneic hematopoietic stem cell transplantation is counterbalanced by the occurrence of life-threatening immune-mediated complications, such as graft-versus-host disease (GVHD), a multistep disease which is reportedly fatal to approximately 15% of transplant recipients. It is now established that T-cell-dendritic cell interactions, T-cell activation, release of proinflammatory cytokines and T-cell trafficking partake in GVHD pathogenesis. This article will focus on the most recent strategies aimed at preventing/treating GVHD by manipulating components of the innate and adaptive immune response from both the donor and the host.

A phase II study of bortezomib plus prednisone for initial therapy of chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) induces significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Corticosteroids are standard initial therapy, despite limited efficacy and long-term toxicity. Based on our experience using bortezomib as effective acute GVHD prophylaxis, we hypothesized that proteasome-inhibition would complement the immunomodulatory effects of corticosteroids to improve outcomes in chronic GVHD (cGVHD). We undertook a single-arm phase II trial of bortezomib plus prednisone for initial therapy of cGVHD. Bortezomib was administered at 1.3 mg/m(2) i.v. on days 1, 8, 15, and 22 of each 35-day cycle for 3 cycles (15 weeks). Prednisone was dosed at .5 to 1 mg/kg/day, with a suggested taper after cycle 1. All 22 enrolled participants were evaluable for toxicity; 20 were evaluable for response. Bortezomib plus prednisone therapy was well tolerated, with 1 occurrence of grade 3 sensory peripheral neuropathy possibly related to bortezomib. The overall response rate at week 15 in evaluable participants was 80%, including 2 (10%) complete and 14 (70%) partial responses. The organ-specific complete response rate was 73% for skin, 53% for liver, 75% for gastrointestinal tract, and 33% for joint, muscle, or fascia involvement. The median prednisone dose decreased from 50 mg/day to 20 mg/day at week 15 (P < .001). The combination of bortezomib and prednisone for initial treatment of cGVHD is feasible and well tolerated. We observed a high response rate to combined bortezomib and prednisone therapy; however, in this single-arm study, we could not directly measure the impact of bortezomib. Proteasome inhibition may offer benefit in the treatment of cGVHD and should be further evaluated.

Current and emerging strategies for the prevention of graft-versus-host disease

Graft-versus-host disease (GVHD) represents the most serious and challenging complication of allogeneic haematopoietic stem-cell transplantation (HSCT). New insights on the role of regulatory T-cells, T cells, and antigen-presenting cells have led to an improved understanding of the pathophysiology of GVHD. However, little progress has been made since the introduction of calcineurin-inhibitor-based regimens in the mid-1980s. Despite standard prophylaxis with these regimens, GVHD still develops in approximately 40-60% of recipients. Thus, there is a need for developing newer approaches to mitigate GVHD, which may facilitate the use of allogeneic HSCT for the treatment of a wider range of haematological cancers. We discuss the rationale, clinical evidence, and outcomes of current (and widely employed) strategies for GVHD prophylaxis, namely calcineurin-inhibitor-based regimens (such as cyclosporine or tacrolimus) combined with methotrexate or mycophenolate mofetil. We assess the clinical evidence for emerging approaches in the prevention of GVHD, including therapies targeting T cells or B cells, the use of mesenchymal stem cells, chemo-cytokine antagonists (such as maraviroc, TNF-α inhibitor, IL-2 receptor antagonist, IL-6 inhibitor), and the use of novel molecular regulators that target multiple cell types simultaneously, including atorvastatin, bortezomib, and epigenetic modulators.

Current issues in chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) is a frequent and potentially life-threatening complication of allogeneic hematopoietic stem cell transplantation. Increased transplantation of older patients and the more frequent use of unrelated donors has led to increased numbers of patients with this painful complication. Recent advances have been made in understanding the pathophysiology of chronic GVHD and in establishing precise criteria for diagnosis and classification of disease manifestations. These advances will hopefully pave the way for improving both the prophylaxis and treatment of chronic GVHD.

Current issues in chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) is a frequent and potentially life-threatening complication of allogeneic hematopoietic stem cell transplantation. Increased transplantation of older patients and the more frequent use of unrelated donors has led to increased numbers of patients with this painful complication. Recent advances have been made in understanding the pathophysiology of chronic GVHD and in establishing precise criteria for diagnosis and classification of disease manifestations. These advances will hopefully pave the way for improving both the prophylaxis and treatment of chronic GVHD.

Rituximab after lymphoma-directed conditioning and allogeneic stem-cell transplantation for relapsed and refractory aggressive non-Hodgkin lymphoma (DSHNHL R3): an open-label, randomised, phase 2 trial

BACKGROUND

Allogeneic stem-cell transplantation has had limited success for patients with refractory and relapsed aggressive B-cell or T-cell lymphoma. We investigated the effect of adding rituximab to standard prophylaxis for graft-versus-host disease after transplantation and estimated overall survival when using a lymphoma-directed myeloablative conditioning regimen.

METHODS

We did this randomised, open-label, phase 2 study at seven German transplantation centres. We enrolled patients with aggressive B-cell or T-cell lymphoma and primary refractory disease, early relapse (<12 months after first-line treatment), or relapse after autologous transplantation. Conditioning with fludarabine (125 mg/m(2)), busulfan (12 mg/kg oral or 9·6 mg/kg intravenous), and cyclophosphamide (120 mg/kg) was followed by allogeneic stem-cell transplantation. Patients were randomly assigned (1:1) to receive rituximab (375 mg/m(2) on days 21, 28, 35, 42, 175, 182, 189, and 196) or not. Allocation was done with a centralised computer-generated procedure; patients were stratified by histological subtype (B-cell vs T-cell lymphoma) and donor match (HLA-identical vs non-identical). Neither investigators nor patients were masked to allocation. The primary endpoints were the incidence of acute graft-versus-host disease grade 2-4 in each treatment group and overall survival at 1 year in both groups combined. All analyses were done for the intention-to-treat population. The study is registered with ClinicalTrials.gov, number NCT00785330.

FINDINGS

Between June 16, 2004, and March 24, 2009, we screened 86 patients and enrolled 84; 42 were randomly assigned to each group. The cumulative incidence of grade 2-4 acute graft-versus-host disease was 46% (95% CI 32-62) in the rituximab group and 42% (95% CI 29-59) in the no rituximab group (hazard ratio [HR] 0·91, 95% CI 0·52-1·60; p=0·74). Overall survival at 1 year for the whole study population was 52% (95% CI 41-62). Grade 4 haematological toxic effects and grade 3 alopecia occurred in all patients. The most common non-haematological grade 5 toxic effects were pneumonia (nine in the no rituximab group vs ten in the rituximab group) and other infections (seven vs four).

INTERPRETATION

The lymphoma-directed myeloablative conditioning regimen developed here is promising for patients with refractory and relapsed aggressive B-cell and T-cell lymphomas. However, the addition of rituximab did not affect the incidence of graft-versus-host disease or overall survival.

FUNDING

Hoffmann-La Roche, Amgen, Astellas Pharma.

Administration of anti-CD20 mAb is highly effective in preventing but ineffective in treating chronic graft-versus-host disease while preserving strong graft-versus-leukemia effects

Chronic graft-versus-host disease (cGVHD) is an autoimmune-like syndrome, and donor B cells play important roles in augmenting its pathogenesis. B cell-depleting anti-CD20 mAb has been administered before or after cGVHD onset for preventing or treating cGVHD in the clinic. Although administration before onset appeared to be more effective, the effect is variable and sometimes minimal. Here, we used 2 mouse cGVHD models to evaluate the preventive and therapeutic effect of anti-CD20 mAb. With the model of DBA/2 donor to MHC-matched BALB/c recipient, 1 intravenous injection of anti-CD20 mAb (40 mg/kg) the following day or on day 7 after hematopoietic cell transplantation when serum autoantibodies were undetectable effectively prevented induction of cGVHD and preserved a strong graft-versus-leukemia (GVL) effect. The separation of GVL effect from GVHD was associated with a significant reduction of donor CD4(+) T cell proliferation and expansion and protection of host thymic medullary epithelial cells. Anti-CD20 mAb administration also prevented expansion of donor T cells and induction of cGVHD in another mouse model of C57BL/6 donor to MHC-mismatched BALB/c recipients. In contrast, administration of anti-CD20 mAb after GVHD onset was not able to effectively deplete donor B cells or ameliorate cGVHD in either model. These results indicate that administration of anti-CD20 mAb before signs of cGVHD can prevent induction of autoimmune-like cGVHD while preserving a GVL effect; there is little effect if administered after cGVHD onset. This provides new insights into clinical prevention and therapy of cGVHD with B cell-depleting reagents.

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.

Graft-versus-host disease: why have we not made more progress?

PURPOSE OF REVIEW

Although allogeneic hematopoietic stem cell transplantation (allo-SCT) is potentially curative for a number of hematologic malignancies, its use is limited by the development of acute and chronic graft-versus-host disease (GVHD). This potentially fatal complication occurs in approximately 50% of allo-SCT recipients.

RECENT FINDINGS

The pathogenesis of acute and chronic GVHD remains poorly understood, methods to prevent it are largely unchanged over the last two decades, and response to front-line treatment with corticosteroids is suboptimal. For patients with steroid-refractory disease, response to second-line treatment is dismal. The prospective clinical studies evaluating new agents for GVHD have been hampered by the inconsistencies in design, making generalization difficult, and few multicenter studies have been conducted.

SUMMARY

Advances have been made over the last decade in grading both acute and chronic GVHD, with the development of biomarkers that provide improved prognostic information in acute GVHD and National Institutes of Health Consensus Criteria for improved grading of chronic GVHD. This, along with the broad understanding of the need to conduct prospective studies with uniform inclusion criteria and endpoints leading to multicenter studies, will hopefully lead to advancements in the prevention of GVHD in the near future.

Post-transplantation B cell activating factor and B cell recovery before onset of chronic graft-versus-host disease

Excessive levels of B cell activating factor (BAFF) are found in patients with active chronic graft-versus-host disease (cGVHD). In mice, BAFF has been shown to be essential for B cell recovery after myeloablation. To assess how BAFF levels relate to transplantation factors and subsequent development of cGVHD, we prospectively monitored 412 patients in the first year after allogeneic peripheral blood or bone marrow hematopoietic stem cell transplantation (HSCT) and censored data at time of cGVHD onset. In patients who did not develop cGVHD, we affirmed a temporal pattern of gradually decreasing BAFF levels as B cell numbers increase after myeloablative conditioning. In contrast, after reduced-intensity conditioning, BAFF levels remained high throughout the first post-HSCT year, suggesting that the degree of myeloablation resulted in delayed B cell recovery associated with persistence of higher BAFF levels. Given that high BAFF/B cell ratios have been associated with active cGVHD, we examined differences in early BAFF/B cell ratios and found significantly different BAFF/B cell ratios at 3 months post-HSCT only after myeloablative conditioning in patients who subsequently developed cGVHD. In addition to HSCT conditioning type, the use of sirolimus was significantly associated with higher BAFF levels after HSCT, and this also was potentially related to lower B cell numbers. Taken together, our results are important for interpreting BAFF measurements in cGVHD biomarker studies.

A phase II study of a nonmyeloablative allogeneic stem cell transplant with peritransplant rituximab in patients with B cell lymphoid malignancies: favorably durable event-free survival in chemosensitive patients

The aim of this prospective phase II trial was to determine the safety and efficacy of a nonmyeloablative conditioning program incorporating peritransplant rituximab in patients with CD20+ B cell non-Hodgkin lymphoma (B-NHL) receiving an allogeneic stem cell transplant (allo-SCT). Fifty-one adult B-NHL patients, with a median age of 54 years, were treated with cyclophosphamide, fludarabine, and 200 cGy of total body irradiation. Rituximab 375 mg/m(2) was given on day -8 and in 4 weekly doses beginning day +21. Equine antithymocyte globulin was given to recipients of volunteer unrelated donor grafts. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate mofetil and tacrolimus, sirolimus, and methotrexate in 8 and 43 patients, respectively. Thirty-three patients received grafts from unrelated donors, and 18 received grafts from matched related donors. All patients engrafted. Full donor chimerism in bone marrow and peripheral T cells was seen in 92% and 89% of patients, respectively, at 3 months after allo-SCT. The cumulative incidence of grades II to IV acute GVHD at 6 months was 25% (95% confidence interval [CI], 13% to 38%) and grades III to IV was 11% (95% CI, 2% to 20%). The 2-year cumulative incidence of chronic GVHD was 29% (95% CI, 15% to 44%). The 2-year event-free and overall survival for all patients was 72% (95% CI, 59% to 85%) and 78% (95% CI, 66% to 90%), respectively. The 2-year event-free survival for chemosensitive patients was 84% (95% CI, 72% to 96%) compared with 30% (95% CI, 2% to 58%) for chemorefractory patients before allo-SCT (P < .001). This nonmyeloablative regimen, with peritransplant rituximab, is safe and effective in patients with B-NHL.