Prior rituximab correlates with less acute graft-versus-host disease and better survival in B-cell lymphoma patients who received allogeneic peripheral blood stem cell transplantation

Cisplatin as a Viable and Secure Alternative to Carmustine in BEAM-Based Conditioning for Autologous Hematopoietic Stem Cell Transplantation in Patients with Lymphoma

BACKGROUND

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) is a standard treatment for relapsed/refractory lymphoma patients. Yet, the widespread use of BEAM is hindered by carmustine accessibility. This study evaluates the efficacy and safety of PEAM (Cisplatin, Etoposide, Cytarabine, and Melphalan) versus BEAM in auto-HSCT for Hodgkin (HL) and non-Hodgkin lymphoma (NHL) patients.

METHODS

We conducted a retrospective single-center study of adult lymphoma patients who received PEAM or BEAM pretransplant conditioning between January 2004 to December 2022, comparing efficacy and safety outcomes.

RESULTS

Among 143 patients (median age of 33 years, 58% males), 55 had HL, and 88 had NHL. The overall response rate (ORR) was 86.7% for PEAM and 72.3% for BEAM, and the relapse rate (RR) was lower for PEAM than BEAM (22.9% vs 45.6%). Median time to relapse (TTR) and overall survival (OS) were not reached for either group. PEAM exhibited a shorter time to both neutrophil (NE) and platelet (PE) engraftment compared to BEAM (10 vs 12 days), with a more tolerable gastrointestinal (GI) toxicity profile.

CONCLUSIONS

Both BEAM and PEAM showed similar outcomes, demonstrating comparable efficacy in terms of ORR, TTR, and OS for both HL and NHL patients. However, PEAM-conditioning was associated with a shorter time to engraftment and fewer GI adverse events.

Pretransplant Blinatumomab Improves Outcomes in B Cell Acute Lymphoblastic Leukemia Patients Who Undergo Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

Blinatumomab, a bispecific monoclonal antibody, effectively controls refractory B cell acute lymphoblastic leukemia (ALL) and promotes measurable residual disease (MRD) negativity. This study investigated the impact of pretransplant blinatumomab on allogeneic hematopoietic cell transplantation (HCT) outcomes in B cell ALL patients.

METHODS

We analyzed the effect of pretransplant blinatumomab on transplant outcomes of 117 adults undergoing allogeneic HCT for B cell ALL at Princess Margaret Hospital, Toronto, between 2010 and 2021. Outcomes assessed included overall survival (OS), graft-versus-host disease and relapse-free survival (GRFS), cumulative incidences of relapse (CIR), and nonrelapse mortality (NRM).

RESULTS

The median follow-up was 36 months. Thirty-one participants (26.5%) received blinatumomab. Blinatumomab group had higher proportions of individuals with high disease risk index, primary induction failure and was more likely to receive dual T cell depletion with antithymocyte globulin and post-transplant cyclophosphamide. Two-year OS, GRFS, NRM, and CIR in the blinatumomab and nonblinatumomab groups were, respectively: 65.4% versus 45.6% (P = .05), 42.2% versus 17.3% (P = .01), 3.2% versus 43.0% (P = .007) and 34.4% versus 14.4% (P = .02). Blinatumomab was associated with a lower incidence of day-100 grade 2 to 4 and grade 3 to 4 acute graft-versus-host disease (aGVHD): 27.5% versus 56.7% (P = .009), and 10.9% versus 34.7% (P = .04), respectively. Multivariate analysis confirmed the association between pretransplant blinatumomab and improved OS and NRM.

CONCLUSIONS

Pretransplant blinatumomab is associated with improved OS and lower risk of NRM in B cell ALL patients undergoing allogeneic HCT, likely reflecting lower burden of treatment-related toxicity in this population. Larger prospective trials are warranted to validate our findings.

Ofatumumab as part of reduced intensity conditioning in high risk B-cell lymphoma patients: final long-term analysis from a prospective multicenter Phase-II Trial

Curative potential of allogeneic transplantation (AlloSCT) in high-risk non-Hodgkin lymphoma (NHL) could be enhanced by the integration of Ofatumumab (OFA), a 2nd generation anti-CD20 moAb, due to an antitumor effect and a role over graft-versus-host disease (GVHD). In this phase II trial (NCT01613300), we investigated safety and effectiveness of OFA-based reduced intensity conditioning (RIC). High-risk B-cell NHL patients with chemorrefractory disease or post-autologous SCT relapse were eligible. OFA was added to a standard RIC regimen. Primary endpoint was grade 3-4 aGVHD rate, while secondary endpoints included CR and survival rates. Thirty-three patients were included (median age 51; diffuse large B-cell:68%, HLA-identical donor: 74%). No grade >2 OFA toxicity was observed. Acute GVHD affected 77% of patients (16% grade 3-4). Remarkably, GVHD achieved CR in 75% of patients after first-line treatment. Chronic GVHD, primarily mild or moderate, occurred in 54% of patients. NHL CR rate at day +100 was 81%. Relapses occurred in 7 patients after a median of 3 months. Causes of death were lymphoma progression (5), infections (10), and GVHD (2). At 24 months, progression-free and overall survival rates were 50.1 and 51.6% respectively. OFA-RIC regimen is safe and effective, though acute GVHD remains a significant complication. However, data suggest that OFA could mitigate its severity.

BAFF blockade attenuates acute graft-versus-host disease directly via the dual regulation of T- and B-cell homeostasis

Introduction

B-cell-activating factor (BAFF) is associated with donor-specific antibodies and chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the effects of BAFF on T-cell physiological function have not been fully elucidated in acute GVHD.

Methods

We examined the effects of belimumab, a monoclonal antibody targeting BAFF, for the treatment of acute GVHD. We examined the effects of T cells and B cells separately when inducing GVHD in mouse model.

Results

Therapeutic functional manipulation of endogenous BAFF can improve acute GVHD during the early post-transplant period. In this study, BAFF was shown to increase the proportions of CD4⁺IL-17⁺, CD4⁺IL-6⁺ Th17, and CD4⁺IFN-γ⁺ Th1 cells and to reduce the proportion of regulatory T (Treg) cells. Furthermore, the belimumab therapy group showed increased B220⁺IgD⁺IgM⁺ mature B cells but decreased B220⁺IgD^-IgM^- memory B cells, B220⁺Fas⁺GL-7⁺ germinal center formation, and B220⁺IgD^-CD138⁺ plasma cells. These results indicate that BAFF can alleviate acute GVHD by simultaneously regulating T and B cells. Interestingly, the BAFF level was higher in patients with acute GVHD after HSCT compared with patients receiving chemotherapy.

Conclusion

This study suggests that BAFF blockade might modulate CD4 +T-cell-induced acute GVHD early after allo-HSCT and the possibility of simultaneously controlling chronic GVHD, which may appear later after allo-HSCT.

Impact of HLA Epitope Matching on Outcomes After Unrelated Bone Marrow Transplantation

The significance of antibody-identified epitopes stimulating humoral alloimmunity is not well understood in the identification of non-permissive human leukocyte antigen (HLA) mismatching patterns in hematopoietic stem cell transplantation (HSCT). This was a retrospective study in a cohort of 9,991 patients who underwent their first HSCT for hematologic malignancies from unrelated bone marrow donors in the Transplant Registry Unified Management Program (TRUMP). HLA eplet mismatches (EMM) were quantified using HLAMatchmaker (HLAMM). The median age of patients was 48 years (range, 16 to 77). The number of EMM in recipient-donor pairs in our study population ranged from 0 to 37 in HLA class I (median, 0) and 0 to 60 in HLA class II (median, 1). In addition to the known high-risk mismatch patterns in the Japanese cohort, HLA-C EMM in the GVH direction was associated with a significantly higher risk for grade III-IV aGVHD, leading to a higher risk of non-relapse mortality and lower overall survival (compared with HLA-C matched patients, HR 1.67, 95% CI 1.44–1.95; HR 1.39, 95% CI 1.25–1.54; HR 1.20, 95% CI 1.10–1.30, respectively). HLAMM-based epitope matching might be useful for identifying patients who are at high risk for serious complications after HSCT from HLA mismatched unrelated donors.

Mature naive B cells regulate the outcome of murine acute graft-versus-host disease in an IL-10 independent manner

Graft-versus-host disease (GVHD) is the main complication of bone marrow transplantation (BMT). T CD4+ lymphocytes are the main effector cells for disease development but other cell types can determine disease outcome through cytokine production and antigen presentation. B cells are abundant in BMT products and are involved in chronic GVHD immunopathogenesis. However, their role in acute GVHD is still unclear. Here, we studied the role of donor resting B cells in a model of acute GVHD. Animals receiving transplants depleted of B cells presented a more severe disease, indicating a protective role for B cells. Mice transplanted with IL-10 KO B cells developed GVHD as severe as those receiving WT B cells. Besides that, mice transplanted with MHC II deficient B cells and as so, unable to present antigen to CD4+ T cells, developed as severe GVHD as animals transplanted without B cells. This result suggests that protection provided by mature naive B cells depends on antigen presentation and not IL-10 production by B cells. In the absence of donor B cells, transplanted mice exhibited disorganized lymphoid splenic tissue. Additionally, donor B cell depletion diminished the follicular T (Tfh)/T effector (Teff) ratio suggesting that protection was correlated with a shift to Tfh differentiation, reducing the number of effector T cells. Importantly, the Tfh/Teff shift impacts disease outcome since observed proinflammatory cytokine levels and tissue damage in target organs were consistent with disease protection. The role of transplanted B cells in the outcome of BMT and the development of acute GVHD should be carefully studied, since these cells are abundant in BMT products and are potent modulator and effector cells in allogeneic response. Extended Abstract Background: B cells are widely known for their ability to produce antibodies. In addition, B cells can act efficiently as antigen-presenting cells, implying the mutual regulation of both T and B lymphocyte subsets. T cell help for B cells has been known for more than 50 years; however, B cell help for T cells, especially regarding the modulation of follicular and regulatory phenotypes, had only lately been explored. Here, we studied the role of resting B cells in a model of systemic inflammatory disease mediated by T cells, graft-versus-host disease (GVHD), which is the main complication of allogeneic bone marrow transplantation. Objetive: The objective of this paper is to investigate the role of donor B cells in acute Graft-versus-Host Disease.

STUDY DESIGN

To investigate the role of donor B cells in aGVHD, we used a full MHC-mismatched bone marrow transplantation model. We infused C57BL/6 BM cells along with splenocytes depleted or not of B220⁺ cells into lethally irradiated BALB/c mice. We also used B cells from IL-10 KO mice to investigate the role of IL-10 produced by donor B cells and B cells from mice which cannot express MHC-II (CIITA KO) to investigate the role of cognate interaction between donor B and T cells.

RESULTS

Animals receiving transplants depleted of B cells presented a more severe disease, showing the existence of B cell-dependent protection. This protection was dependent on the T cell-B cell cognate interaction but not on IL-10 or Treg induction. In the absence of donor B cells, transplanted mice exhibited fewer GCs and a lower follicular T (Tfh)/T effector (Teff) ratio than mice transplanted in the presence of B cells. Protection was correlated with a shift to Tfh differentiation, reducing the number of effector cells. Importantly, the Tfh/Teff shift impacts disease outcome with less T cell-mediated disease due to more B cell-dependent Tfh generation with fewer effector T cells and lower proinflammatory cytokine levels detected in target organs.

CONCLUSION

We show that B-cell depleted bone marrow transplantation leads to a more severe disease, with earlier mortality related to increased organ damage. Such differences depend on cognate interactions between T cells and B cells, are IL-10 independent and are related to a shift in the differentiation of lymphocytes from the follicular helper phenotype to the effector phenotype. Therefore, Teffs, which are circulating cells, become relatively more numerous and can reach and damage the target tissues. These results point to caution in the early posttransplantation elimination of donor B cells. It is not a matter of eliminating only antibody-forming cells or cells that mediate Tfh generation but of B cells, which interact and modulate T cell activity, impacting a disease that is not antibody mediated.

Immune Suppression in Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for high-risk hematologic disorders. There are multiple immune-mediated complications following allo-HSCT that are prevented and/or treated by immunosuppressive agents. Principal among these immune-mediated complications is acute graft-versus-host disease (aGVHD), which occurs when the new donor immune system targets host tissue antigens. The immunobiology of aGVHD is complex and involves all aspects of the immune system. Due to the risk of aGVHD, immunosuppressive aGVHD prophylaxis is required for nearly all allogeneic HSCT recipients. Despite prophylaxis, aGVHD remains a major cause of nonrelapse mortality. Here, we discuss the clinical features of aGVHD, the immunobiology of aGVHD, the immunosuppressive therapies used to prevent and treat aGVHD, how to mitigate the side effects of these immunosuppressive therapies, and what additional immune-mediated post-allo-HSCT complications are also treated with immunosuppression.

Impact of Rituximab and Host/Donor Fc Receptor Polymorphisms after Allogeneic Hematopoietic Cell Transplantation for CD20+ B Cell Malignancies

We previously reported a 24% 1-year relapse rate in 93 older or medically unfit patients with CD20⁺ B cell malignancies after allogeneic hematopoietic cell transplantation (HCT) with low-intensity conditioning. The current prospective study tested the hypothesis that disease relapse could be reduced and overall survival (OS) improved by peritransplantation administration of rituximab (RTX). Sixty-three patients received RTX (375 mg/m²/day) on days -3, +10, +24, and +38 along with 2 to 3 Gy total body irradiation with or without fludarabine (30 mg/m² for 3 days). Median RTX levels of >25 μg/mL were achieved through day +84 after transplantation, but RTX level was not correlated with relapse or graft-versus-host disease (GVHD). HCT recipients with F/F and V/F FCγRIIIa polymorphisms showed a trend toward a higher relapse rate compared with those with V/V polymorphism (P= .15). No difference in outcome was found based on V/V donor pairing. Five-year relapse rates were similar between RTX-treated patients and historical controls (32% versus 28%; P = .94). RTX-treated patients had greater 5-year OS (47% versus 38%; P = .13) and progression-free survival (41% versus 32%; P = .12) compared with historical controls who underwent HCT without RTX, although the difference was not statistically significant. The incidence of acute GVHD was similar in the 2 groups (grade II-IV, 57% versus 56%; grade III-IV, 13% versus 17%), but the 5-year incidence of chronic GVHD was higher among RTX-treated patients (62% versus 47%). In patients with relapsed or refractory non-Hodgkin lymphoma, peritransplantation RTX neither reduced relapse nor improved GVHD. The role of donor-recipient pairing by FCγRIIIa polymorphisms in outcomes remains to be determined.

R-BEAM versus Reduced-Intensity Conditioning Regimens in Patients Undergoing Allogeneic Stem Cell Transplantation for Relapsed Refractory Diffuse Large B Cell Lymphoma

Allogeneic stem cell transplant (alloSCT) is considered in diffuse large B cell lymphoma (DLBCL) patients with chemorefractory disease or who have relapsed after autologous SCT. Here we present the first report of alloSCT using the R-BEAM (rituximab, carmustine, etoposide, cytarabine, melphalan) conditioning regimen in DLBCL patients. We retrospectively compared long-term alloSCT outcomes of DLBCL patients who received either R-BEAM (n = 47) or reduced-intensity conditioning (RIC) regimens (n = 23). Seventy patients (median age, 53 years) with DLBCL received alloSCT between January 2005 and December 2017. The median number of pretransplant therapies was 3, and 17 patients (24%) received prior autologous SCT. All received rituximab as a frontline or salvage therapy before alloSCT. The donor was unrelated in 42 patients (60%), and peripheral blood stem cells were commonly used (96%). The 6-month cumulative incidence of grades III to IV acute graft-versus-host disease (GVHD) was 36.2% and 8.7% for R-BEAM and RIC, respectively (P = .03). Median follow-up of surviving patients after R-BEAM and RIC was 3.1 and 5.5 years, respectively. Three-year overall survival (OS) after R-BEAM and RIC was 34.4% and 43.4%, respectively (P = .48). At 3 years, R-BEAM was associated with a similar relapse rate (25.5% versus 26.1%, P = .96), nonrelapse mortality (NRM; 39.7% versus 39.1%, P = .98), and relapse-free survival (RFS; 34.8% versus 34.7%, P = .75) compared with RIC. In multivariable analysis lower Karnofsky performance score was associated with lower OS (hazard ratio, .96; P = .05), whereas chemorefractory disease was associated with a higher relapse risk (hazard ratio, 8.8; P = .04). No difference in OS, relapse, NRM, or RFS was noticed between R-BEAM and RIC. R-BEAM regimen seems to be feasible and results in equivalent rates of long-term OS, relapse, NRM, and RFS compared with RIC. However, a significantly higher rate of severe acute GVHD was noticed.

Outcome of Rituximab-Based Treatment for Post-Transplant Lymphoproliferative Disorder After Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Experience

Background

Post-transplant lymphoproliferative disorder (PTLD) is a rare complication following solid organ transplantation and allogeneic hematopoietic stem cell transplantation (Allo-HSCT), which gives rise to high mortality rates.

Material/Methods

This was a single-center retrospective analysis based on 27 patients who were diagnosed with PTLD following Allo-HSCT between January 1, 2007 and June 2018 at the Chinese PLA General Hospital. The purpose of this analysis was to investigate responses and prognostic factors of rituximab-based treatment.

Results

Twenty-seven patients were treated with rituximab. Among them, 20 of 27 patients (74.07%) had a complete response, 2 of 27 patients (7.41%) had a partial response, 5 of 27 patients (18.52%) had no response, and 22 of 27 patients (81.48%) cleared Epstein-Barr virus (EBV) copies. There were no obvious side effects. The 1-year overall survival (OS) estimate was 46.8% (95% CI, 23.1–65.5%). Univariate analysis revealed that lower OS was correlated with Eastern Cooperative Oncology Group (ECOG) score standard (3–4), Epstein-Barr virus (EBV) viral load (≥10⁶ copies/mL), bacteria or fungal infection, and EBV reactivation were positive after treatment with 1 or 2 doses of rituximab (P<0.05). Multivariate analysis showed that each of the following were independently associated with lower OS (P<0.05): female, ECOG score standard (3–4), and EBV reactivation were positive after treatment with 1 or 2 doses of rituximab.

Conclusions

Our results demonstrated that rituximab-based treatment was a safe and effective strategy for patients who were diagnosed with PTLD following Allo-HSCT. The identified prognostic factors may help to detect which PTLD patients are at a higher risk of mortality.

TCR αβ+/CD19+ cell depletion in haploidentical hematopoietic allogeneic stem cell transplantation: a review of current data

Allogeneic hematopoietic stem cell transplantation is a curative option for patients with a variety of diseases. Transplantation from a related haploidentical donor is being increasingly utilized for patients who lack an available human leukocyte antigen matched related or unrelated donor. One of the strategies used for haploidentical transplants involves selective depletion of T cells expressing the αβ T cell receptor and CD19+ B cells prior to transplant. This allows for the removal of cells responsible for graft-versus-host disease and post-transplant lymphoproliferative disorder but maintains hematopoietic progenitor and stem cells for engraftment (CD34+ cells), as well as cells to elicit graft-versus-tumor effect and provide anti-infective activity (such as gamma-delta T cells and natural killer cells). The aim of this review article is to present and discuss the data available to date from studies utilizing this method of transplantation.

Risk factors predisposing to the development of hypogammaglobulinemia and infections post-Rituximab

Rituximab (RTX) is a monoclonal antibody against CD20, commonly used in the treatment of hematological malignancies and autoimmune diseases. The use of RTX is related to the development of hypogammaglobulinemia and infections. Aim of this review is to summarize the evidence supporting the association of specific risk factors with the development of hypogammaglobulinemia and infections post-RTX. Immunological complications are more common in patients with malignant diseases as compared to non-malignant diseases. Moreover, the use of more than one dose of RTX, maintenance regimens, low pre-treatment basal immunoglobulin levels and the association with Mycophenolate and purine analogues represent risk factors for the development of hypogammaglobulinemia. The number of RTX courses, the evidence of low IgG levels for more than 6 months, the use of G-CSF, the occurrence of chronic lung disease, cardiac insufficiency, extra-articular involvement in patients with rheumatoid arthritis, low levels of IgG and older age have been correlated with a higher risk of infections. Even though the heterogeneity of the studies in terms of study population age and underlying disease, RTX schedules as well as differences in pre-treatment or concomitant therapy doesn't allow drawing definitive conclusions, the study of the literature highlight the association of specific risk factors with the occurrence of hypogammaglobulinemia and/or infections. A long term randomized controlled clinical trial could be useful to define a personalized evidence-based risk management plan for patients treated with RTX.

Management of Epstein-Barr Virus infections and post-transplant lymphoproliferative disorders in patients after allogeneic hematopoietic stem cell transplantation: Sixth European Conference on Infections in Leukemia (ECIL-6) guidelines

Epstein-Barr virus-related post-transplant lymphoproliferative disorders are recognized as a significant cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation. To better define current understanding of post-transplant lymphoproliferative disorders in stem cell transplant patients, and to improve its diagnosis and management, a working group of the Sixth European Conference on Infections in Leukemia 2015 reviewed the literature, graded the available quality of evidence, and developed evidence-based recommendations for diagnosis, prevention, prophylaxis and therapy of post-transplant lymphoproliferative disorders exclusively in the stem cell transplant setting. The key elements in diagnosis include non-invasive and invasive methods. The former are based on quantitative viral load measurement and imaging with positron emission tomography; the latter with tissue biopsy for histopathology and detection of Epstein-Barr virus. The diagnosis of post-transplant lymphoproliferative disorder can be established on a proven or probable level. Therapeutic strategies include prophylaxis, preemptive therapy and targeted therapy. Rituximab, reduction of immunosuppression and Epstein-Barr virus-specific cytotoxic T-cell therapy are recommended as first-line therapy, whilst unselected donor lymphocyte infusions or chemotherapy are options as second-line therapy; other methods including antiviral drugs are discouraged.

Donor-to-Recipient ABO Mismatch Does Not Impact Outcomes of Allogeneic Hematopoietic Cell Transplantation Regardless of Graft Source

The impact of ABO mismatch has been studied on various hematopoietic cell transplant (HCT) outcomes, including neutrophil and platelet engraftment, pure red cell aplasia, acute and chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), and overall survival (OS). Yet conflicting results have been reported. However, the impact of ABO mismatch on transplant outcomes with various graft types has not been carefully investigated. We analyzed the impact of various graft sources and type of ABO mismatch on transplant outcomes for 1502 patients who underwent HCT at the University of Minnesota between 2000 and 2014: 312 receiving marrow (BM), 475 filgrastim-mobilized blood (peripheral blood stem cell [PBSC]), and 715 umbilical cord blood (UCB) grafts. Neutrophil engraftment by day 28 was marginally less frequent in the bidirectional ABO mismatched transplants receiving UCB, whereas ABO matching had no influence on engraftment in the BM or PBSC cohorts. ABO mismatch led to no significant differences in platelet engraftment irrespective of stem cell source. We observed a modest but not significantly lower incidence of grades II/IV acute GVHD in the bidirectional ABO mismatched transplants in the UCB and the PBSC cohorts but not in the BM group. We found a higher incidence of chronic GVHD in the PBSC group, but it was not significantly lower in the minor ABO mismatched transplants. The incidence of chronic GVHD was similar in the major ABO mismatched transplants receiving BM. We found no significant difference in the OS and NRM between ABO matched and ABO mismatched transplants within each of the 3 graft source groups. Multivariable analysis adjusting for other relevant factors confirmed that ABO match status did not significantly influence the outcomes of either engraftment, acute or chronic GVHD or NRM. We conclude that ABO mismatch does not influence the outcomes of allogeneic HCT, regardless of stem cell source.

Impact of Immune-Modulatory Drugs on Regulatory T Cell

Immunosuppression strategies that selectively inhibit effector T cells while preserving and even enhancing CD4FOXP3 regulatory T cells (Treg) permit immune self-regulation and may allow minimization of immunosuppression and associated toxicities. Many immunosuppressive drugs were developed before the identity and function of Treg were appreciated. A good understanding of the interactions between Treg and immunosuppressive agents will be valuable to the effective design of more tolerable immunosuppression regimens. This review will discuss preclinical and clinical evidence regarding the influence of current and emerging immunosuppressive drugs on Treg homeostasis, stability, and function as a guideline for the selection and development of Treg-friendly immunosuppressive regimens.

ABO blood group antigen mismatch has an impact on outcome after allogeneic peripheral blood stem cell transplantation

ABO blood group antigen incompatibility (ABO mismatch) is not an obstacle to allogeneic stem cell transplantation (allo-SCT). However, the impact on clinical outcome after allo-SCT remains controversial. We analyzed 512 patients after allogeneic peripheral blood SCT (allo-PBSCT) for an association of ABO mismatch with transfusion requirements, myeloid and platelet engraftment, the incidence of GvHD, relapse, transplant-related mortality (TRM), and overall survival (OS). A total of 260 patients underwent ABO-mismatched transplantation and the control group consisted of 252 patients with ABO-matched allo-PBSCT. We found a significant association between major-0 ABO mismatch (group 0 recipient/group A, B, or AB donor) and increased red blood cell (RBC) and platelet transfusion requirements (both P<.001) as well as delayed platelet engraftment (P<.001). Minor-A (group A recipient/group 0 donor) and minor-AB (group AB recipient/group 0, A, or B donor) ABO mismatch was significantly associated with an increased TRM after allo-PBSCT (P=.001 and P=.02). In multivariate analysis performed using Cox regression, minor ABO mismatch appeared as independent risk factor for TRM after allo-PBSCT. No association was found for ABO mismatch with the incidence of GvHD, relapse, and OS. Our results suggest that ABO blood group mismatch has a significant impact on the outcome and that minor-A and minor-AB ABO mismatch represents a risk factor for increased TRM after allo-PBSCT.

The Role of Biomarkers in the Diagnosis and Risk Stratification of Acute Graft-versus-Host Disease: A Systematic Review

Allogeneic hematopoietic cell transplantation (HCT) is an increasingly used curative modality for hematologic malignancies and other benign conditions. Attempts to reduce morbidity and mortality and improve survival in patients undergoing HCT are crucial. The ability to diagnose acute graft-versus-host disease (aGVHD) in a timely manner, or to even predict aGVHD before clinical manifestations, along with the accurate stratification of these patients, are critical steps to improve the treatment and outcomes of these patients. Many novel biomarkers that may help achieve these goals have been studied recently. This overview is intended to assist clinicians and investigators by providing a comprehensive review and analytical interpretation of the current knowledge concerning aGVHD and biomarkers likely to prove useful in diagnosis and risk stratification of this condition, along with the difficulties that hamper this approach.

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.

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.

Rituximab for indolent lymphomas before and after allogeneic hematopoietic stem cell transplantation

PURPOSE OF REVIEW

The most substantial advancement in the treatment of indolent B-cell non-Hodgkin lymphoma (NHL), since the advent of combination chemotherapy, has been the introduction of the monoclonal anti-CD20 antibody rituximab. However, the optimal schedule, timing, and duration of rituximab therapy remain controversial.

RECENT FINDINGS

Since its initially reported single-agent activity in 1997, the role of rituximab has greatly expanded and it is now ubiquitously integrated in all treatment phases of indolent NHL. Yet, several questions remain to be addressed: should asymptomatic patients be treated at diagnosis with single-agent rituximab or still kept in watchful waiting, what are the optimal first-line treatments to combine with rituximab, what is the role of maintenance therapy, and is there a benefit in incorporating rituximab in autologous and allogeneic stem cell transplantation schemes for these diseases? Recent and ongoing clinical trials tackling these relevant issues will be presented and critically discussed in this article.

SUMMARY

Excellent outcomes are reported with rituximab therapy in indolent NHL, both early and late in the disease course. Continued study of this most valuable therapeutic agent is warranted to set the optimal treatment approach leading to cure the majority of patients.

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.

ABO mismatch is associated with increased nonrelapse mortality after allogeneic hematopoietic cell transplantation

We evaluated ABO associated outcomes in 1737 patients who underwent allogeneic hematopoietic cell transplantation (allo-HCT) at Stanford University between January 1986 and July 2011. Grafts were 61% ABO matched, 18% major mismatched (MM), 17% minor MM, and 4% bidirectional MM. Median follow-up was 6 years. In multivariate analysis, overall survival (OS) was inferior in minor MM hematopoietic cell transplantations (median 2.1 versus 6.3 years; hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.19 to 2.05; P = .001) in comparison with ABO-matched grafts. ABO minor MM was associated with an increase in early nonrelapse mortality (NRM) (18% versus 13%; HR, 1.48; 95% CI, 1.06 to 2.06; P = .02). In an independent Center for International Blood and Marrow Transplant Research (CIBMTR) analysis of 435 lymphoma patients receiving mobilized peripheral blood grafts, impairment of OS (HR, 1.55; 95% CI, 1.07 to 2.25; P = .021) and increased NRM (HR, 1.72; 95% CI, 1.11 to 2.68; P = .03) were observed in recipients of ABO minor-MM grafts. A second independent analysis of a CIBMTR data set including 5179 patients with acute myeloid leukemia and myelodysplastic syndrome identified a nonsignificant trend toward decreased OS in recipients of ABO minor-MM grafts and also found ABO major MM to be significantly associated with decreased OS (HR, 1.19; 95% CI, 1.08 to 1.31; P < .001) and increased NRM (HR, 1.23; 95% CI, 1.08 to 1.4; P = .002). ABO minor and major MM are risk factors for worse transplantation outcomes, although the associated hazards may not be uniform across different transplantation populations. Further study is warranted to determine which patient populations are at greatest risk, and whether this risk can be modified by anti-B cell therapy or other peri-transplantation treatments.

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.

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.

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.

Outcomes of human leukocyte antigen-matched sibling donor hematopoietic cell transplantation in chronic lymphocytic leukemia: myeloablative versus reduced-intensity conditioning regimens

Allogeneic hematopoietic cell transplantation (HCT) can cure some chronic lymphocytic leukemia (CLL) subjects. This study compared outcomes of myeloablative (MA) and reduced-intensity conditioning (RIC) transplants from HLA-matched sibling donors (MSD) for CLL. From 1995 to 2007, information regarding 297 CLL subjects was reported to the Center of International Blood and Marrow Transplant Research; of these, 163 underwent MA and 134 underwent RIC MSD HCT. The MA subjects underwent transplantation less often after 2000 and less commonly received antithymocyte globulin (4% versus 13%, P = .004) or prior antibody therapy (14% versus 53%; P < .001). RIC was associated with a greater likelihood of platelet recovery and less grade 2 to 4 acute graft-versus-host disease compared with MA conditioning. One- and 5-year treatment-related mortality (TRM) were 24% (95% confidence intervals [CI], 16% to 33%) versus 37% (95% CI, 30% to 45%; P = .023), and 40% (95% CI, 29% to 51%) versus 54% (95% CI, 46% to 62%; P = .036), respectively, and the relapse/progression rates at 1 and 5 years were 21% (95% CI, 14% to 29%) versus 10% (95% CI, 6% to 15%; P = .020), and 35% (95% CI, 26% to 46%) versus 17% (95% CI, 12% to 24%; P = .003), respectively. MA conditioning was associated with better progression-free (PFS) (relative risk, .60; 95% CI, .37 to .97; P = .038) and 3-year survival in transplantations before 2001, but for subsequent years, RIC was associated with better PFS and survival (relative risk, 1.49 [95% CI, .92 to 2.42]; P = .10; and relative risk, 1.86 [95% CI, 1.11 to 3.13]; P = .019). Pretransplantation disease status was the most important predictor of relapse (P = .003) and PFS (P = .0007) for both forms of transplantation conditioning. MA and RIC MSD transplantations are effective for CLL. Future strategies to decrease TRM and reduce relapses are warranted.

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.

Acute graft-versus-host disease: a bench-to-bedside update

Over the past 5 years, many novel approaches to early diagnosis, prevention, and treatment of acute graft-versus-host disease (aGVHD) have been translated from the bench to the bedside. In this review, we highlight recent discoveries in the context of current aGVHD care. The most significant innovations that have already reached the clinic are prophylaxis strategies based upon a refinement of our understanding of key sensors, effectors, suppressors of the immune alloreactive response, and the resultant tissue damage from the aGVHD inflammatory cascade. In the near future, aGVHD prevention and treatment will likely involve multiple modalities, including small molecules regulating immunologic checkpoints, enhancement of suppressor cytokines and cellular subsets, modulation of the microbiota, graft manipulation, and other donor-based prophylaxis strategies. Despite long-term efforts, major challenges in treatment of established aGVHD still remain. Resolution of inflammation and facilitation of rapid immune reconstitution in those with only a limited response to corticosteroids is a research arena that remains rife with opportunity and urgent clinical need.

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.

Accelerated therapeutic progress in diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma in the world. Clinically, biologically, and pathologically, DLBCL is a heterogeneous entity with a range of potential outcomes. Immunochemotherapy regimens, consisting of the chimeric monoclonal anti-CD20 antibody rituximab in combination with chemotherapy, have improved the outcomes. Relapsed DLBCL is generally treated with salvage immunochemotherapy followed by high-dose therapy and autologous stem cell transplantation; however, DLBCL is not yet curable in up to a third of patients. The real promise for cure lies in novel agents and their rational combinations. The improved understanding of DLBCL subtypes and gene expression profiling has led to the identification of targeted drugs that may allow for subtype specific therapy. We have summarized the existing data on the prognostic factors and the treatment of DLBCL, including the use of novel agents such as lenalidomide, carfilzomib, and ibrutinib. We also share our thoughts on the direction of future clinical trials.

Recent progress in managing graft-versus-host disease and viral infections following allogeneic stem cell transplantation

Despite recent reductions in transplant-related mortality, post-transplant complications such as graft-versus-host disease (GvHD) remain major obstacles to the successful application of allogeneic hematopoietic transplantation. Steroid-refractory GvHD has a poor outcome. Although there are a variety of new approaches to the treatment of refractory GvHD, many have limited evidence of efficacy. Other approaches appear to be unacceptably toxic. It would be preferable to improve GvHD prophylaxis. There is good evidence that rates of GvHD can be reduced without unacceptable reduction of the graft-versus-leukemia effect or compromising overall survival. However, prophylactic measures aimed at reducing T-cell numbers or functions are associated with high rates of reactivation of latent viruses. New technologies that allow rapid generation of virus-specific T-cells show promise to reduce the frequency and severity of such reactivations and have the potential to revolutionize the approach to post-transplant infectious complications.

The role of allogeneic haematopoietic progenitor cell transplantation in patients with diffuse large B-cell non-Hodgkin lymphomas (DLBCL)

Despite the undoubted improvement in the prognosis of patients with diffuse large B-cell lymphomas (DLBCLs) with the addition of rituximab in the front-line treatment, a significant proportion of patients still relapse. Salvage immune-chemotherapy followed by high-dose therapy with autologous haematopoietic cell transplantation (auto-HCT) remains the treatment of choice for such patients, especially in those who demonstrate chemosensitive disease. In recent years, allogeneic haematopoietic cell transplantation (allo-HCT) has increasingly been used for patients who are resistant to salvage treatment or relapse after an auto-HCT. Strategies using reduced intensity conditioning regimens have allowed application of this approach to a broader range of patients. PFS is up to 55% with a risk of relapse up to 80% depending on different studies. In multivariate analysis, several factors have been associated with favourable outcome including chemosensitivity of the disease, younger age and Karnofsky performance status at the time of the transplant being the strongest ones. DLIs have shown to induce durable responses in relapsed or progressed disease; however, its role remains controversial as the results are inferior to the responses seen in other haematological malignancies. More recently, the addition of MoAbs in the non-myeloablative conditioning regimens has shown encouraging results. In conclusion, allo-HCT is a feasible option in selective patients with chemosensitive DBCL, as it reduces the risk of relapse; however, this is achieved at the cost of significant non-relapse mortality.

Prevention of graft-vs.-host disease

INTRODUCTION

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment for many malignant and non-malignant hematologic disorders. However, graft-vs.-host disease (GVHD) remains a major complication of allogeneic HCT and limits the success of this approach.

AREAS COVERED

This paper reviews recent developments in the prevention of acute and chronic GVHD. In the setting of acute GVHD prevention, recent trials of T-cell depletion using Fresenius-ATG are reviewed, as well as studies testing total lymphoid irradiation, mesenchymal stromal cells, rituximab, statins, sirolimus and other investigational agents. In the setting of chronic GVHD, results with Fresenius-ATG are reviewed, as well as B-cell depletion with rituximab, and the potential role of the B-cell regulatory cytokine BAFF in chronic GVHD is also discussed. Finally, the emerging role of resident skin and gut bacterial flora-the so-called microbiome-in the pathogenesis of GVHD is covered.

EXPERT OPINION

Current methods of acute GVHD prevention are highly successful, and a number of investigational approaches promise to further reduce the risk of this complication. By contrast, chronic GVHD is more poorly understood and more difficult to prevent. Future studies are required to delineate the roles of these approaches and to abrogate GVHD without sacrificing the beneficial immunologic graft-vs.-tumor effect.

Graft-versus-host disease: part II. Management of cutaneous graft-versus-host disease

Dermatologists are ideally suited to manage the various cutaneous sequelae of graft-versus-host disease (GVHD) outlined in part I of this review. However, the complexity of the patient with GVHD, including comorbidities, potential drug interactions related to polypharmacy, and the lack of evidence-based treatment guidelines, are significant challenges to optimizing patient care. In this section, we will provide an outline for the role of the dermatologist in a multispecialty approach to caring for patients with GVHD.

Prophylactic rituximab after allogeneic transplantation decreases B-cell alloimmunity with low chronic GVHD incidence

B cells are involved in the pathogenesis of chronic GVHD (cGVHD). We hypothesized that prophylactic anti-B-cell therapy delivered 2 months after transplantation would decrease allogeneic donor B-cell immunity and possibly the incidence of cGVHD. Therefore, in the present study, patients with high-risk chronic lymphocytic leukemia (n = 22) and mantle-cell lymphoma (n = 13) received a total lymphoid irradiation of 80 cGy for 10 days and antithymocyte globulin 1.5 mg/kg/d for 5 days. Rituximab (375 mg/m(2)) was infused weekly on days 56, 63, 70, and 77 after transplantation. The incidence of acute GVHD was 6%. The cumulative incidence of cGVHD was 20%. Nonrelapse mortality was 3%. Rituximab treatment after allogeneic transplantation significantly reduced B-cell allogeneic immunity, with complete prevention of alloreactive H-Y Ab development in male patients with female donors (P = .01). Overall survival and freedom from progression at 4 years for chronic lymphocytic leukemia patients were 73% and 47%, respectively; for mantle-cell lymphoma patients, they were 69% and 53%, respectively.

Genetic variation in recipient B-cell activating factor modulates phenotype of GVHD

B-cell activating factor (BAFF) single nucleotide polymorphisms (SNPs) are associated with autoimmune diseases. Because patients with classic and overlap chronic GVHD (cGVHD) have features of autoimmune diseases, we studied the association of recipient and/or donor BAFF SNPs with the phenotype of GVHD after allogeneic stem cell transplantation. Twenty tagSNPs of the BAFF gene were genotyped in 164 recipient/donor pairs. GVHD after day 100 occurred in 124 (76%) patients: acute GVHD (aGVHD) subtypes (n = 23), overlap GVHD (n = 29), and classic cGVHD (n = 72). In SNP analyses, 9 of the 20 tag SNPs were significant comparing classic/overlap cGVHD versus aGVHD subtypes/no GVHD. In multivariate analyses, 4 recipient BAFF SNPs (rs16972217 [odds ratio = 2.72, P = .004], rs7993590 [odds ratio = 2.35, P = .011], rs12428930 [odds ratio2.53, P = .008], and rs2893321 [odds ratio = 2.48, P = .009]) were independent predictors of GVHD subtypes, adjusted for conventional predictors of cGVHD. This study shows that genetic variation of BAFF modulates GVHD phenotype after allogeneic stem cell transplantation.

Rituximab for prevention and treatment of graft-versus-host disease

Growing understanding of the important role of B lymphocytes in alloreactivity has paved the way for evaluating anti-B cell therapy with rituximab in patients undergoing allogeneic hematopoietic cell transplantation. Data suggesting a beneficial reduction in incidence and severity of acute graft-versus-host disease (GVHD) are limited to non-randomized studies from single institutions using higher than conventional doses of rituximab. Additionally, rituximab is used as an effective treatment of corticosteroid-refractory chronic GVHD with good responses, particularly in cases of dermatologic and mucosal involvement. Post-transplant administration of rituximab appears to reduce the rate of chronic GVHD in preliminary studies.

Current and future approaches for control of graft-versus-host disease

Graft-versus-host disease (GVHD), both acute and chronic, remains one of the major barriers to improving outcomes after allogeneic stem cell transplantation. The pathophysiology of GVHD is complex and incompletely understood. GVHD is believed to arise from the interaction of: tissue damage and proinflammatory cytokines causing activation of antigen-presenting cells (APCs, donor T-cell activation by APCs and cytokines and host tissue injury by effector T lymphocytes and proinflammatory cytokines. There is also a role for additional lymphocyte subtypes (naive and memory T cells, regulatory T cells, natural killer T cells and B cells) in GVHD pathogenesis. Strategies to improve donor-recipient HLA match, and to minimize conditioning toxicity, cytokine release and APC and effector T-lymphocyte activation, will likely improve prophylaxis of acute (and possibly chronic) GVHD. Therapy of established acute and chronic GVHD is still heavily dependent on corticosteroids, despite their limited efficacy and considerable toxicity. Novel agents (and/or combinations of agents) comprising pharmacologic, biologic and cellular therapies targeting specific steps or subsets involved in immune activation will likely comprise future advances in GVHD control. This article reviews the current state of knowledge regarding the prevention and treatment of acute and chronic GVHD. Novel approaches currently undergoing evaluation are also highlighted.

In vivo B-cell depletion with rituximab for alternative donor hemopoietic SCT

We retrospectively analyzed 55 patients given a fixed dose of rituximab (200 mg) on day+5 after an alternative donor transplant, to prevent EBV DNA-emia; 68 alternative transplants who did not receive prophylactic rituximab served as controls. The two groups were comparable for donor type, and all patients received anti-thymocyte globulin in the conditioning regimen. Rituximab patients had a significantly lower rate of EBV DNA-emia 56 vs 85% (P=0.0004), a lower number of maximum median EBV copies (91 vs 1321/10(5) cells, P=0.003) and a significantly lower risk of exceeding 1000 EBV copies per 10(5)cells (14 vs 49%, P=0.0001). Leukocyte and lymphocyte counts were lower on day +50 and+100 in rituximab patients, whereas Ig levels were comparable. The cumulative incidence of grade II-IV acute GvHD was significantly reduced in rituximab patients (20 vs 38%, P=0.02). Chronic GvHD was comparable. There was a trend for a survival advantage for patients receiving rituximab (46 vs 40%, P=0.1), mainly because of lower transplant mortality (25 vs 37%, P=0.1). Despite the drawback of a retrospective study, these data suggest that a fixed dose of rituximab on day +5 reduces the risk of a high EBV load, and also reduces acute GvHD.

Anti-CD20 monoclonal antibodies and their use in adult autoimmune hematological disorders

Autoimmune hematological disorders encompass a broad group of hematological conditions characterized by the loss of self-tolerance to a variety of antigens. Despite good response to first-line therapy in the majority of patients, relapses are common, necessitating new and safe therapeutic options. The anti-CD20 monoclonal antibody rituximab has led to substantial improvement in the treatment of malignant and immune-mediated disorders involving B cells. Although experience with rituximab in immune-mediated hematological disorders is rarely supported by randomized trials, there is now substantial experience with rituximab suggesting that anti-CD20 therapy is an effective and well-tolerated alternative to immunosuppressive therapy in these disorders. However, caution is needed based on recent reports describing-sometimes severe-rituximab-related complications.

(90)Y-ibritumomab tiuxetan followed by reduced-intensity conditioning and allo-SCT in patients with advanced follicular lymphoma

RIC HSCT is a potentially curative therapeutic option for patients with advanced FL but disease relapse remains the most common cause of failure. Radioimmunoconjugates administered prior to RIC allogeneic HSCT may enhance cytoreduction and allow more time for graft versus lymphoma effect to develop without the associated toxicity of a myeloablative HSCT. We performed a retrospective study to describe the outcomes of patients with relapsed, refractory or transformed FL who received ⁹⁰Y ibritumomab tiuxetan followed by fludarabine and low-dose busulfan RIC allogeneic HSCT at the Dana-Farber Cancer Institute between 2006 and 2009, inclusively. Twelve patients were identified with a median age of 55 (40–66) years and a median number of lines of therapy of 5 (2–10). Two patients (17%) had transformed to a more aggressive histology and 5 (42%) had chemorefractory FL. Cumulative incidences of grade II–IV acute GVHD at 100 days were 17% (± 11%) and chronic GVHD at 12 months were 63% (±19%). Two-year non-relapse mortality was 18% (± 12%). Two-year OS and progression-free survival (PFS) were 83% (± 11%) and 74% (± 13%), respectively. This treatment is associated with favorable outcomes including acceptable rates of GVHD and relapse in advanced FL patients and warrants prospective studies.

Targeted IV busulfan and fludarabine followed by post-allogeneic hematopoietic cell transplantation rituximab demonstrate encouraging activity in CD20+ lymphoid malignancies without increased risk of infectious complications

We examined pharmacokinetic-targeted IV busulfan (75-170 mg/m(2), with target AUC of 3500-6000 μmol min) and fludarabine (40 mg/m(2)) × 4 days with rituximab (t-IV Bu/Flu + rituximab) 375 mg/m(2) on days +1 and +8 followed by allogeneic hematopoietic cell transplantation in 19 patients (median age 56, range 35-68 years) with CD20+ lymphoid malignancies. Median time to neutrophil and platelet engraftment was 15 and 12 days. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 58% (95% confidence interval, CI 39-85%), and chronic GVHD was 50% (95% CI 28-88%). With a median follow up of 7 (range 1-31) months, overall response was observed in 15, and stable or progressive disease in 4. Overall survival at 1 year was 67%. Engraftment, chimerism, and infectious complications did not differ significantly from a contemporaneous non-rituximab containing comparator group. The addition of rituximab 375 mg/m(2) to t-IV Bu/Flu does not appear to adversely affect engraftment, donor chimerism, or increase the risk of infectious complications.