Clinical applications of rituximab in allogeneic stem cell transplantation: Anti-tumor and immunomodulatory effects

Applying Rituximab During the Conditioning Regimen Prevents Epstein-Barr Virus Infection Following Allogeneic Hematopoietic Stem Cell Transplant in a Children's Cohort: A Retrospective Case-Control Study

INTRODUCTION

Since hematopoietic stem cell transplant (HSCT) is an important therapy for malignant and non-malignant pediatric diseases, improving transplant-related mortality remains a challenge. Currently, rituximab, a monoclonal antibody of anti-CD20, is widely used for several post-HSCT complications. However, few studies have focused on the application of rituximab before HSCT.

METHODS

We conducted a retrospective case-control study from January 2019 to July 2021 to determine this effect in a single center. Forty-eight patients were included in the rituximab group, with a one-to-one ratio matched to the control group.

RESULTS

Both the occurrence rate and cumulative incidence rate of Epstein-Barr virus (EBV) infection were significantly lower in the rituximab group than in the without-rituximab group (10.4% vs. 33.3%, p = 0.014 and 12.2% vs. 39.3% p = 0.0026, respectively). Furthermore, without the application of rituximab was identified as a risk factor for post-HSCT EBV infection via both univariate [hazard ratio (HR) = 4.17, 95%CI (1.52-11.43), p = 0.005] and multivariate analyses [HR = 4.65, 95%CI (1.66-13.0), p = 0.003]. Although the overall survival (OS) probability of the rituximab group was comparable to the without-rituximab group, a markedly improved OS of the rituximab group was found in the malignant disease subgroup (78.9% vs. 42.1%, p = 0.032). The outcomes of graft-versus-host disease, neutrophil and platelet engraftment, other viral infections, and the reconstitution of lymphocytes showed no significant differences between the two groups.

CONCLUSIONS

The administration of rituximab before HSCT may prevent EBV infection following HSCT.

The impact of Rituximab administered before transplantation in patients undergoing allogeneic hematopoietic stem cell transplantation: A real-world study

Rituximab is used to eliminate B cells as a chimeric monoclonal antibody directed against CD20, a B-cell antigen expressed on B cells. To explore the impact of rituximab administered before transplantation, we implemented a retrospective, monocentric study and utilized real-world data collected at our center between January 2018 and December 2020, and then followed until December 2021. Based on whether a dose of 375mg/m2 rituximab was used at least once within two weeks before transplantation, patients undergoing allo-HSCT were classified into two groups: rituximab (N=176) and non-rituximab (N=344) group. Amongst all the patients, the application of rituximab decreased EBV reactivation (P<0.01) and rituximab was an independent factor in the prevention of EBV reactivation by both univariate and multivariate analyses (HR 0.56, 95%CI 0.33-0.97, P=0.04). In AML patients, there were significant differences in the cumulative incidence of aGVHD between the two groups (P=0.04). Our data showed that rituximab was association with a decreased incidence of aGVHD in AML patients according to both univariate and multivariate analyses. There was no difference between the two groups in other sets of populations. Thus, our study indicated that rituximab administered before transplantation may help prevent EBV reactivation in all allo-HSCT patients, as well as prevent aGVHD in AML patients after allo-HSCT.

Tertiary Lymphatic Structures in Primary Hepatic Carcinoma: Controversy Cannot Overshadow Hope

Tertiary lymphoid structures (TLSs) are organized aggregates of immune cells found in the tumor microenvironment. TLS can influence primary hepatic carcinoma (PHC) occurrence and have an active role in cancer. TLS can promote or inhibit the growth of PHC depending on their location, and although available findings are controversial, they suggest that TLS have a protective role in PHC tissues and a non-protective role in paracancerous tissues. In addition, the cellular composition of TLS can also influence the outcome of PHC. As an immunity marker, TLS can act as a marker of immunotherapy to predict its effect and help to identify patients who will respond well to immunotherapy. Modulation of TLS formation through the use of chemokines/cytokines, immunotherapy, or induction of high endothelial vein to interfere with tumor growth has been studied extensively in PHC and other cancers. In addition, new tools such as genetic interventions, cellular crosstalk, preoperative radiotherapy, and advances in materials science have been shown to influence the prognosis of malignant tumors by modulating TLS production. These can also be used to develop PHC treatment.

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.

[Immunologic changes in diffuse large B-cell lymphomas after rituximab-CHOP treatment: own data and review of the literature]

INTRODUCTION

Rituximab treatment may induce a long-term B-cell depletion, which can be accompanied with an increased infection risk.

AIMS

To examine the changes of the white blood cell, CD19+ B-cell and CD4+ T-cell counts and the levels of immunoglobulin G, A, M after rituximab containing chemotherapy and to explore the infectious complications in our patients and review of the literature.

PATIENTS AND METHODS

Thirty-five diffuse large B-cell lymphoma patients were examined, who were treated with rituximab-cyclophosphamide-vincristine-doxoribicine-prednisolone (R-CHOP). The B- and T-cell populations were analyzed with flow-cytometry while the immunoglobulin levels were measured by nephelometry.

RESULTS

CD19+ B-lymphocytes were undetectable after the treatment and their count only increased from the post-therapeutic 12th month. Infection did not occur in this group of patients.

CONCLUSIONS

Rituximab induced B-cell depletion was appreciable also in this group of patients, while serious or unexpected infection did not occur. Increased infectious risk primarily can be observed after long-term, maintenance rituximab treatment.

Oral chronic graft-versus-host disease: current pathogenesis, therapy, and research

Optimal management of complex autoimmune diseases requires a multidisciplinary medical team including dentists to care for lesions of the oral cavity. In this review, we discuss the presentation, prevalence, diagnosis, and treatment of oral manifestations in chronic graft-versus-host disease (cGVHD), which is a major late complication in patients treated by allogeneic hematopoietic stem cell transplantation. We assess current general knowledge of systemic and oral cGVHD and present general treatment recommendations based on literature review and our clinical experience. Additionally, we review areas where the understanding of oral cGVHD could be improved by further research and address tools with which to accomplish the long-term goal of providing better health and quality of life to patients with cGVHD.

The chemokine system in allogeneic stem-cell transplantation: a possible therapeutic target?

Further improvements in allogeneic stem-cell transplantation will probably depend on a better balance between immunosuppression to control graft-versus-host disease and immunological reconstitution sufficient to ensure engraftment, reduction of infection-related mortality and maintenance of post-transplant antileukemic immune reactivity. The chemokine network is an important part of the immune system, and, in addition, CXCL12/CXCR4 seem to be essential for granulocyte colony-stimulating factor-induced stem-cell mobilization. Partial ex vivo graft T-cell depletion based on the expression of specific chemokine receptors involved in T-cell recruitment to graft-versus-host disease target organs may also become a future therapeutic strategy; an alternative approach could be pharmacological inhibition (single-receptor inhibitors or dual-receptor inhibitors) in vivo of specific chemokine receptors involved in this T-cell recruitment. Future clinical studies should therefore be based on a better characterization of various immunocompetent cells, including their chemokine receptor profile, both in the allografts and during post-transplant reconstitution.

The lack of memory B cells including T cell independent IgM+ IgD+ memory B cells in chronic graft-versus host disease is associated with susceptibility to infection

The chronic graft-versus host disease (cGVHD) is associated with a perturbed B cell homeostasis and an increased infection rate. Aiming to determine the impact of lymphocyte subsets on cGVHD, blood samples from 98 patients at least 100 days following allogeneic haematopoietic stem cell transplantation (median 1066 days) were analyzed, serum levels of immunoglobulins measured and the incidence of severe infections retrospectively documented. Absolute CD19(+) B cell counts, including counts of immature (CD10(+) CD38(++) CD20(+) IgM(++)) and transitional (CD10(-) CD38(++) CD20(+) IgM(++)) as well as class switched memory (CD19(+) CD27(+) IgM(-) IgD(-)) B cells in patients with active cGVHD (n = 52) were significantly decreased as compared to those with inactive (n = 18) or without cGVHD (n = 28). In addition, nonclass switched IgM(+) memory B cells (CD19(+) CD27(+) IgM(+) IgD(+)) were absent in patients with cGVHD, but not in patients with inactive (0.4 × 10(6) /l) or without (1.7 × 10(6) /l) cGVHD (both P < 0.001). In line with these results we found significantly decreased lgG levels in patients with cGVHD, which was associated with a significantly higher rate of severe infections in cGVHD patients. Our data underline the close association of diminished B cell counts with cGVHD and the onset of severe infections. The lack of IgM(+) memory B cells in patients with cGVHD may indicate functional asplenia.

Allogeneic mesenchymal stem cell therapy for refractory cytopenias after hematopoietic stem cell transplantation

BACKGROUND

Posttransplant cytopenias are a severe complication after allogeneic stem cell transplantation (allo-SCT) and their origin is often multifactorial or unknown. They are frequently refractory to standard therapy, which may include steroids and/or immunoglobulins. Mesenchymal stem cells (MSCs) are an attractive therapeutic tool in the allo-SCT setting for the ability to enhance engraftment as well as acting as immunosuppressants for graft-versus-host disease. There is no prior experience in the literature of the use of MSCs to treat cytopenias after allo-SCT.

CASE REPORTS

In this work we report for the first time four cases of refractory posttransplant cytopenias (three patients with thrombocytopenia and one with neutropenia) that were treated with MSCs from a third-party donor. MSCs were expanded from 100 mL of marrow obtained under standard good manufacturing practice conditions. Most patients received more than one cell dose, and median dose of MSCs administered was 1 × 10(6) /kg.

RESULTS

All patients recovered normal blood counts, with a mean follow-up of 12.5 months. There were no adverse events related to MSC administration.

CONCLUSION

MSC therapy may contribute to the recovery of refractory posttransplant peripheral cytopenias in patients undergoing allo-SCT.

Approaches to relapse after allogeneic stem cell transplantation

PURPOSE OF REVIEW

Relapse has become the leading cause of death following allogeneic hematopoietic stem cell transplantation (HSCT). Despite improved understanding of the biology that underlies the graft-versus-leukemia/tumor effect the relapse rate did not decrease over the past 20 years. In general, prognosis is poor for patients who relapsed to an allograft since effective treatment options are limited. Here, we review the available and upcoming treatment approaches for relapse.

RECENT FINDINGS

Treatment of relapse after allogeneic HSCT has been rarely investigated systematically and results differ substantially from diseases. Withdrawal of immunosuppressive medication, donor lymphocyte infusions with or without chemotherapy and/or second allogeneic HSCT are the most used options. New specific cellular approaches such as disease-specific T-cells, alloreactive natural killer cells or vaccination strategies are under investigation. Novel agents such as tyrosine-kinase inhibitors, hypomethylating agents, monoclonal antibodies, immunomodulating drugs, or proteasome-inhibitors either alone or in combination with adoptive immunotherapy are upcoming promising options, but valid data are lacking so far.

SUMMARY

With some exceptions (chronic myeloid leukemia), treatment options for patients who relapse are limited. The results are poor and the majority of patients ultimately die of their disease. More effort and research is needed to prevent and treat relapse after allogeneic HSCT.

Allogeneic hematopoietic stem cell transplantation overcomes the adverse prognostic impact of CD20 expression in acute lymphoblastic leukemia

CD20 expression is associated with early recurrence and inferior survival in precursor-B acute lymphoblastic leukemia patients treated with chemotherapy. Whether CD20 influences outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is unknown. We analyzed CD20 expression on blasts at diagnosis in 157 patients who underwent allo-HSCT in the first complete remission (57%) or the second complete remission (43%). Of 125 evaluable patients, 71 were ≥ 20 years of age. CD20 expression was observed in 58 patients (46%; 52% of children, 39% of adults). There was no association between age, Ph(+) status, white blood cell count at diagnosis, and CD20 positivity. After allo-HSCT, disease-free survival at 5 years was 48% for all patients, 55% (95% confidence interval 40%-67%) for CD20(+) patients, and 43% (95% confidence interval 30%-54%) for CD20(-) patients (P = .15). Relapse did not differ between the groups. These results can serve as a reference to evaluate incorporation of anti-CD20 therapeutics to HSCT for the CD20(+) acute lymphoblastic leukemia subset. Clinical trial numbers for www.clinicaltrials.gov are NCT00365287, NCT00305682, and NCT00303719.

Liposomes modified by carbohydrate ligands can target B cells for the treatment of B-cell lymphomas

Evaluation of: Chen WC, Completo GC, Sigal DS, Crocker PR, Saven A, Paulson JC. In vivo targeting of B-cell lymphoma with glycan ligands of CD22. Blood 115(23), 4778-4786 (2010). A strategy has been developed to deliver selectively chemotherapeutic drugs to B cells by employing doxorubicin-loaded liposomes modified by a ligand for the B-cell-specific cell-surface protein CD22, also known as Siglec-2. The liposomes bound in a rapid and saturable manner to the human Burkitt lymphoma Daudi B-cell line and exhibited significantly higher cytotoxicity in vitro and in vivo compared with similar untargeted liposomes. The CD22-targeted liposome bound to B cells isolated from lymphoma patients and although binding was proportional to CD22 expression on the cell surface, low levels of expression on chronic lymphocytic leukemia cells were sufficient to effect cell neutralization. The glycan-based strategy for delivery of chemotherapeutic agents may provide a new strategy for the treatment of B-cell lymphomas.

Gene expression profile of cytokines in patients with chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation with reduced conditioning

There are no reliable markers useful to predict the onset or the evolution of chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT), although several candidate biomarkers have been identified from limited hypothesis-driven studies. In this study we evaluated 14 patients who received a reduced intensity conditioning HSCT. Seven patients had cGVHD, whereas 7 never developed cGVHD during the period of observation. The expression of 114 cytokines in immunoselected cell populations was explored by microarray analysis and 11 cytokines were selected for further evaluation by real-time PCR. Differential gene expression measurements showed a significant up-regulation for INFγ (interferon, gamma) in CD8+ and for TNFSF3 (tumor necrosis factor superfamily, member 3) and for TNFSF10 (tumor necrosis factor superfamily, member 10) in CD14+ cell population when comparing cGVHD with control samples. The expression levels were significantly decreased for TNFSF10 in CD8+ cell population and for TNFSF12 (tumor necrosis factor superfamily, member 12) and for PDGFβ (platelet-derived growth factor, beta) in CD4+. Our data seem to suggest that different immune populations can play a role in cGVHD pathogenesis and the early detection of gene expression profile in these patients could be useful in the monitoring of GVHD. We hypothesized that PDGFβ down-regulation could represent a negative feedback to compensate for enhanced expression of its receptor recently reported.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: Report from the Committee on Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is a major cause of treatment failure after allogeneic hematopoietic stem cell transplantation (alloHSCT). Treatment options for relapse have been inadequate, and the majority of patients ultimately die of their disease. There is no standard approach to treating relapse after alloHSCT. Withdrawal of immune suppression and donor lymphocyte infusions are commonly used for all diseases; although these interventions are remarkably effective for relapsed chronic myelogenous leukemia, they have limited efficacy in other hematologic malignancies. Conventional and novel chemotherapy, monoclonal antibody therapy, targeted therapies, and second transplants have been utilized in a variety of relapsed diseases, but reports on these therapies are generally anecdotal and retrospective. As such, there is an immediate need for well-designed, disease-specific trials for treatment of relapse after alloHSCT. This report summarizes current treatment options under investigation for relapse after alloHSCT in a disease-specific manner. In addition, recommendations are provided for specific areas of research necessary in the treatment of relapse after alloHSCT.

The role of B cells in transplantation and immunopathic diseases

B cells, by virtue of their diverse roles in immune responses to foreign and self antigens, have become of increasing interest to the clinician as well as the basic immunologist. In particular, it is now apparent that the development of B cell unresponsiveness in antibody and T cell mediated autoimmune disorders and the transplant setting is both worthwhile and achievable.

Immune reconstitution after allogeneic transplantation and expanding options for immunomodulation: an update

Allogeneic hematopoietic stem cell transplantation (HSCT) has advanced to a common procedure for treating also older patients with malignancies and immunodeficiency disorders by redirecting the immune system. Unfortunately, cure is often hampered by relapse of the underlying disease, graft-versus-host disease, or severe opportunistic infections, which account for the majority of deaths after HSCT. Enhancing immune reconstitution is therefore an area of intensive research. An increasing variety of approaches has been explored preclinically and clinically: the application of cytokines, keratinocyte growth factor, growth hormone, cytotoxic lymphocytes, and mesenchymal stem cells or the blockade of sex hormones. New developments of allogeneic HSCT, for example, umbilical cord blood or haploidentical graft preparations leading to prolonged immunodeficiency, have further increased the need to improve immune reconstitution. Although a slow T-cell reconstitution is regarded as primarily responsible for deleterious infections with viruses and fungi, graft-versus-host disease, and relapse, the importance of innate immune cells for disease and infection control is currently being reevaluated. The groundwork has been prepared for the creation of individualized therapy partially based on genetic features of the underlying disease. We provide an update on selected issues of development in this fast evolving field; however, we do not claim completeness.