Rituximab-associated acute thrombocytopenia: an under-diagnosed phenomenon

Risk factors of rituximab-induced thrombocytopenia in patients with autoimmune bullous diseases

Rituximab has been the mainstay treatment for autoimmune bullous diseases (AIBDs). Among the side effects of rituximab, rituximab-induced thrombocytopenia (RIT) is a rare but critical complication. However, there have been no reports or identification of risk factors for RIT in patients with AIBD. In our retrospective study, we compared rituximab-treated AIBD in patients with and without thrombocytopenia to explore the risk factors. In addition, we compared two different rituximab protocols (rheumatoid arthritis [RA] and lymphoma) in terms of the incidence and severity of thrombocytopenia. A total of 222 patients were enrolled, and 46 patients (20.7%) developed RIT. Multivariate logistic regression analysis identified age and chronic kidney disease (CKD) as significant factors for RIT. We also found that patients treated with the lymphoma protocol demonstrated a significantly higher mean post-rituximab platelet count compared with those on the RA protocol. This was the first analysis, to our knowledge, of risk factors for RIT in patients with AIBD. Individuals aged 70 or older and those with multiple comorbidities, particularly CKD, should be closely monitored for thrombocytopenia. For patients with CKD, it may be safer to use the lymphoma protocol for rituximab administration as it results in a lesser reduction in post-rituximab platelet count.

Impact of Rituximab and Corticosteroids on Late Cytopenias Post-Chimeric Antigen Receptor T Cell Therapy

Chimeric antigen receptor (CAR) T cell therapy represents a significant advancement in the treatment of patients with relapsed/refractory B cell lymphoid malignancies. Cytokine release syndrome and immune effector cell-associated neurotoxicity represent the most acute serious adverse events post CAR T cell therapy but the occurrence and persistence of cytopenias post CAR T cell therapy represent a significant adverse event and a management challenge. While most patients typically recover blood counts by 30 days, a significant subset of patients have persistent or late cytopenias beyond 30 days. Patients receiving CAR T cell are heavily pre-treated and the impact of prior therapies on late cytopenias is not well understood. In this study, we found an association between increased number of rituximab infusions and/or cumulative rituximab dose received prior to CAR T cell infusion and persistent anemia and thrombocytopenia at 90 and 180 days afterwards. An overall increased number of prior lines of therapy was also associated with persistent lymphopenia and anemia at 90 days while receiving a prior autologous hematopoietic cell transplant was associated with a greater risk of neutropenia and lymphopenia.

What Therapeutic Regimen Will Be Optimal for Initial Clinical Trials of Pig Organ Transplantation?

We discuss what therapeutic regimen might be acceptable/successful in the first clinical trial of genetically engineered pig kidney or heart transplantation. As regimens based on a calcineurin inhibitor or CTLA4-Ig have proved unsuccessful, the regimen we administer to baboons is based on induction therapy with antithymocyte globulin, an anti-CD20 mAb (Rituximab), and cobra venom factor, with maintenance therapy based on blockade of the CD40/CD154 costimulation pathway (with an anti-CD40 mAb), with rapamycin, and a corticosteroid. An anti-inflammatory agent (etanercept) is administered for the first 2 wk, and adjuvant therapy includes prophylaxis against thrombotic complications, anemia, cytomegalovirus, and pneumocystis. Using this regimen, although antibody-mediated rejection certainly can occur, we have documented no definite evidence of an adaptive immune response to the pig xenograft. This regimen could also form the basis for the first clinical trial, except that cobra venom factor will be replaced by a clinically approved agent, for example, a C1-esterase inhibitor. However, none of the agents that block the CD40/CD154 pathway are yet approved for clinical use, and so this hurdle remains to be overcome. The role of anti-inflammatory agents remains unproven. The major difference between this suggested regimen and those used in allotransplantation is the replacement of a calcineurin inhibitor with a costimulation blockade agent, but this does not appear to increase the complications of the regimen.

Rituximab induced acute thrombocytopenia in a patient with systemic lupus erythematosus: a case report

BACKGROUND

Rituximab is a novel chimeric monoclonal antibody that has established itself as a potent therapeutic option for autoimmune medical conditions, including systemic lupus erythematosus, owing to its mechanism of action targeting CD20 cells. Rituximab is also known to cause a spectrum of side effects including hematological abnormalities. Acute isolated thrombocytopenia following rituximab is an uncommon occurrence and, when seen, occurs in the presence of underlying hematological malignancies. Its occurrence in autoimmune diseases is rare. Despite this, acute isolated thrombocytopenia in the backdrop of systemic lupus erythematosus is undocumented.

CASE PRESENTATION

A young 36-year-old South Asian female with systemic lupus erythematosus with class IV lupus nephritis poorly responding to standard therapy was initiated on rituximab. Ten days later, she presented with mucocutaneous bleeding and ecchymotic skin lesions. Isolated severe thrombocytopenia was noted with a platelet count of 5 × 10⁹/L (150-450). Anticipating life-threatening bleeding, she was given intravenous immunoglobulin, methyl prednisolone, and platelet transfusion considering a spectrum of initial differential diagnosis. Rituximab was also withheld. Though extensively investigated, most investigations were negative. A platelet destructive process was suspected as bone marrow biopsy showed adequate megakaryocytes. Weighing the risk versus benefit, following recovery, she was reinitiated on rituximab. Within 4 days, she presented again with similar symptoms and severe isolated thrombocytopenia was noted. Rituximab-induced acute thrombocytopenia was considered the working clinical diagnosis.

CASE DISCUSSION AND CONCLUSION

Rituximab can cause a spectrum of hematological abnormalities, including isolated acute thrombocytopenia. Its occurrence in autoimmune conditions is rare, and its manifestation in systemic lupus erythematosus is undocumented. Its exact etiology is still disputed. Usually considered benign, the platelet numbers tend to show improvement with cessation of therapy. However, in the presence of mucocutaneous bleeding in our patient, we took an aggressive approach to management. Though evidence for corrective therapy is anecdotal, it could be justified on the basis of averting potential catastrophic hemorrhagic manifestations. The spectrum of autoimmune disease that potentially predisposes rituximab to cause thrombocytopenia should be extended to include systemic lupus erythematosus.

Rituximab-induced acute thrombocytopenia in patients with splenomegaly B Cell lymphoma: an underdiagnosed but severe complication

Rituximab is popularly used in the treatment of B-cell lymphomas that bear CD20 antigen. Most of the adverse events (AEs) induced by rituximab are infusion-related symptoms. However, rituximab-induced acute thrombocytopenia (RIAT), which often develops within the 1-3 days after rituximab administration, is relatively unusual, severe, and usually self-recovering. Until now, most of the reports about RIAT were described as case reports and RIAT often occurred in patients with mantle cell lymphoma (MCL). Here, we report two patients who developed severe RIAT, one patient had a refractory and relapsed follicular lymphoma (FL), and the other patient was newly diagnosed with splenic marginal zone lymphoma (SMZL). RIAT is a rare, under-diagnosed but serious adverse event that should arouse attention to clinicians, and routine blood count monitoring should be considered after the administration of rituximab, especially for high-risk lymphoma patients or patient with splenomegaly.

Successful rechallenge of rituximab following severe rituximab-induced acute thrombocytopenia in a patient with splenic marginal zone lymphoma

Rituximab-induced acute thrombocytopenia (RIAT) is a relatively rare complication of rituximab treatment that has been infrequently reported in a number of patients with malignant lymphoma. Most commonly encountered in mantle cell lymphoma, the extent to which RIAT occurs in splenic marginal zone lymphoma is unknown. In this report, we describe a case of RIAT in a patient with splenic marginal zone lymphoma. Rituximab was safely rechallenged with increased premedications and slowed infusion rate. While the exact mechanism of this phenomenon has yet to be elucidated, diligent monitoring of platelet counts following rituximab infusion can be considered in high-risk patients to avoid potential adverse events. Split dose rituximab for high-risk patients may provide an alternative approach to improve patient safety.

A Case of Rituximab-Induced Acute Thrombocytopenia in a Patient with Splenic Marginal Zone Lymphoma and Chronic Hepatitis C Virus Infection

Patient: Female, 46

Final Diagnosis: Rituximab induced acute thrombocytopenia

Symptoms: Abdominal discomfort

Medication:—

Clinical Procedure: —

Specialty: Hematology

Disseminated Intravascular Coagulation-like Reaction after Rituximab Infusion in a Patient with Nephrotic Syndrome

Several case series have suggested that rituximab is efficacious in adult patients with minimal change disease. We herein report a case of disseminated intravascular coagulation-like reaction after rituximab infusion in a patient with nephrotic syndrome. A 58-year-old Japanese man with minimal change disease diagnosed 15 years earlier was started on rituximab to prevent relapse of nephrotic syndrome when he presented to our clinic with low albuminemia, massive proteinuria, and leg edema. Eleven days after rituximab infusion, he presented with abdominal pain, appetite loss, and tarry stool. A laboratory examination revealed severe thrombocytopenia and coagulopathy, and upper gastrointestinal endoscopy revealed multiple hemorrhagic ulcers in his esophagus and stomach. The patient died two days later. Physicians should consider disseminated intravascular coagulation-like reaction when encountering cases with thrombocytopenia after rituximab infusion for any disease.

Spontaneous Splenic Rupture and Rituximab-Induced Acute Thrombocytopenia in a Patient with High-Risk Mantle Cell Lymphoma

Mantle cell lymphoma is a relatively rare type of mature B-cell non-Hodgkin's lymphoma with an incidence of approximately 8 cases per million persons per year. In patients with mantle cell lymphoma, there are rare case reports of the potentially life-threatening consequences of splenic rupture and rituximab-induced acute thrombocytopenia (RIAT) occurring separately, but there are no reports of these occurring in the same patient. Whilst rare, they are important to be aware of as early detection may prevent fatal outcomes.

Early and late hematologic toxicity following CD19 CAR-T cells

Autologous T cells transduced with CD19-directed chimeric antigen receptors have recently been approved by several regulatory agencies for the treatment of relapsed and refractory leukemia and lymphoma, after demonstrating remarkable remission rate in advanced patients. The most common adverse events reported are cytokine-release syndrome (CRS), neurotoxicity, and hematologic toxicity. Here, we focus on early and late cytopenia occurring after CD19 CAR-T cells in 38 patients treated with CD19 CAR-T cells. Neutropenia, thrombocytopenia, and anemia occur frequently (94, 80, and 51%, respectively) after CAR-T cell infusion, and are associated with a biphasic nature, as in 93% of patients hematologic toxicity occurs after 21 days from cell infusion. Late hematologic toxicity was more common in patients with high grade CRS and in patients treated after a recent stem cell transplantation. Interestingly, since these events occur late after the lymphodepleting chemotherapy and after resolution of CRS, we found perturbations in SDF-1 levels to correlate with events of late neutropenia, likely associated with B-cell recovery.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Rituximab-induced Acute Thrombocytopenia in Granulomatosis with Polyangiitis

A 72-year-old Japanese woman diagnosed with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis was admitted to our hospital with hearing loss, temporal pain, and sudden blindness. We finally diagnosed recurrent granulomatosis with polyangiitis and initiated methyl-prednisolone pulse therapy (1,000 mg) followed by prednisolone (30 mg/day) and rituximab (RTX). After the third RTX administration, she developed bloody stools along with acute thrombocytopenia and low complement levels. We diagnosed rituximab-induced acute thrombocytopenia (RIAT), and her platelet counts spontaneously recovered. This case suggests that after RTX therapy RIAT may sometimes cause severe thrombocytopenia, and that monitoring the complements may be useful for making an early diagnosis of RIAT.

Rituximab-induced Acute Thrombocytopenia in a Patient with Follicular Lymphoma: A Case Report and Review of the Literature

Rituximab is a highly effective agent that is used in the treatment of B-cell lymphoma. Rituximab-induced acute thrombocytopenia is a rare side effect that has previously been reported in a small number of patients with malignant lymphoma; its mechanism is still unknown. We herein report the case of a 74-year old man who was diagnosed with follicular lymphoma and who developed severe acute thrombocytopenia the day after the administration of rituximab. Coagulation abnormality, which mimicked disseminated intravascular coagulation, also appeared. When physicians use rituximab to treat high-risk patients, the platelet count should be closely monitored to avoid possible adverse events.

Intravenous immunoglobulin-induced acute thrombocytopenia

BACKGROUND

Intravenous immunoglobulin (IVIG) has known efficacy in various hematologic conditions, including immune thrombocytopenic purpura.

STUDY DESIGN AND METHODS

We present the clinical course of a patient with splenic marginal zone lymphoma, who developed acute thrombocytopenia on three consecutive episodes, with nadir counts of 27 × 10⁹ , 50 × 10⁹ , and 9 × 10⁹ /L, upon administration of Intratect IVIG for hypogammaglobulinemia. An immunofluorescence test applying flow cytometry and monoclonal antibody immobilization of platelet antigens (MAIPA) assay were used to evaluate the reaction between IgG present in the IVIG preparations and the patient's or healthy donors' platelets (PLTs).

RESULTS

A strong direct binding reaction was observed between the patient's PLTs and Intratect IgG using both methods. A similar reaction failed to materialize with controls. Binding was not antigen specific according to MAIPA.

CONCLUSIONS

This is the first reported case of thrombocytopenia as a possible adverse effect of IVIG.

Theranostic of biopharmaceuticals

Monoclonal antibodies (mAbs) and fusion proteins with an Fc portion of immunoglobulin G (IgG) are emblematic of the remarkable expansion of biopharmaceuticals. Despite their biological origin, these products display an interindividual variability in their efficacy and/or side effects, which must be taken into consideration. Biological monitoring allowing for adapted prescription and dose adjustments may lead to therapeutic optimization and limitation of the high costs of these drugs. Herein, we review the biological theranostic of mAbs and Fc fusion proteins, including pre-treatment analyses, monitoring of efficacy, therapeutic drug monitoring, and monitoring of side effects. Supported by concrete evidence, a specific interest is given to individualised therapeutic monitoring that combines intention to treat, biomarkers of efficacy and adaptation of serum concentrations.

Disseminated intravascular coagulation-like reaction following rituximab infusion

Rituximab generally is a well-tolerated medication used in a variety of haematological and autoimmune conditions. The safety profile of the medication has been reviewed in the literature. Infusion reactions due to cytokine release are the most common side effects. With the increased use of rituximab, there is an increase incidence of cytopenias, most commonly thrombocytopenia and leucopenia. Coagulopathy is quite rare, reported previously in four cases in the literature. We highlighted the clinical course of a 39-year-old patient with precursor B-cell acute lymphoblastic leukaemia who was started on rituximab infusion. The patient developed a cytokine-release syndrome with haemodynamic instability, followed by rapid-onset cytopenias and disseminated intravascular coagulation abnormalities characterised by coagulopathy with fibrinolysis and mucocutaneous bleeding. The report is followed by a review of the literature. It is important to recognise rituximab-induced coagulopathy early as part of the differential diagnosis of thrombocytopenia and disseminated intravascular coagulation following rituximab administration.

Immune pancytopenia after chemotherapy in a patient with diffuse large B-cell lymphoma

During treatment for malignant lymphoma, cytopenia can develop for several reasons. In the treatment of cytopenia, various possibilities should be considered because inadequate treatment causes exacerbation of cytopenia and can lead to fatal conditions, such as infection and bleeding. Herein, we describe immune pancytopenia 3 months after the last exposure to chemotherapy in a patient with diffuse large B-cell lymphoma (DLBCL). She suffered from severe pancytopenia after two courses of rituximab and bendamustine therapy for a second relapse of DLBCL. Immune pancytopenia was diagnosed with bone marrow tests and the presence of autoantibodies; it promptly resolved after initiation of prednisolone therapy. Clinicians should be aware of immune cytopenia and monitor for it carefully, even if patients have already finished chemotherapy treatment.

[Rituximab-induced acute thrombocytopenia in a patient with chronic lymphocytic leukemia]

INTRODUCTION

Rituximab is a chimeric anti-CD20 monoclonal antibody generally well tolerated. However, a severe but rare rituximab-related immune-toxic syndrome, associating fever, chills and thrombocytopenia can occur shortly after the infusion.

CASE REPORT

We report a case of severe acute rituximab-induced thrombocytopenia with favorable outcome in a patient with chronic lymphocytic leukemia and discuss the possible underlying mechanisms.

CONCLUSION

Despite the potential initial severity of rituximab-induced thrombocytopenia in CLL, chemotherapy should not be discontinued; tolerance might increase as the hematologic disorder is controlled.

Rituximab-induced Acute Thrombocytopenia in High Tumor Burden Follicular Lymphoma

Rituximab-induced acute thrombocytopenia (RIAT), a rare complication of rituximab administration, has not yet been described in follicular lymphoma (FL). A 65-year-old man received rituximab for the treatment of high tumor burden follicular lymphoma in the leukemic phase. The next day, his platelet count abruptly dropped from 85,000 to 5,000/μL, which spontaneously recovered in a few days without specific treatment. We speculate that the occurrence of infusion-related cytokine release syndrome in rituximab-sensitive high tumor burden FL contributed to the development of RIAT. Frequent monitoring of the platelet count is advisable for select patients considered to be at a high risk for RIAT.

Early-onset neutropenia induced by rituximab in a patient with lupus nephritis and hemolytic anemia

Rituximab is an anti-CD20 monoclonal antibody that has been used to treat several complications of systemic lupus erythematosus (SLE) including nephritis, cerebritis, and hematological disorders. Neutropenia is among the adverse events associated with rituximab; this usually occurs several weeks after therapy. However, early-onset neutropenia has been reported only in a few cases. Herein, we describe a 36-year-old Hispanic SLE woman who developed severe early-onset neutropenia (0.3 × 10⁹/L) after the second weekly rituximab infusion (375 mg/m² weekly × 4) given for nephritis and hemolytic anemia. She also had early-onset thrombocytopenia after rituximab therapy. Both hematological disorders resolved 12 days after the fourth and final dose. This case, together with few others, suggests that early-onset neutropenia may occur during rituximab therapy. Even though rituximab-induced neutropenia seems to be transient, it may predispose SLE patients to severe complications such as infections.

Monoclonal antibody therapy and renal transplantation: focus on adverse effects

A series of monoclonal antibodies (mAbs) are commonly utilized in renal transplantation as induction therapy (a period of intense immunosuppression immediately before and following the implant of the allograft), to treat steroid-resistant acute rejections, to decrease the incidence and mitigate effects of delayed graft function, and to allow immunosuppressive minimization. Additionally, in the last few years, their use has been proposed for the treatment of chronic antibody-mediated rejection, a major cause of late renal allograft loss. Although the exact mechanism of immunosuppression and allograft tolerance with any of the currently used induction agents is not completely defined, the majority of these medications are targeted against specific CD proteins on the T or B cells surface (e.g., CD3, CD25, CD52). Moreover, some of them have different mechanisms of action. In particular, eculizumab, interrupting the complement pathway, is a new promising treatment tool for acute graft complications and for post-transplant hemolytic uremic syndrome. While it is clear their utility in renal transplantation, it is also unquestionable that by using these highly potent immunosuppressive agents, the body loses much of its innate ability to mount an adequate immune response, thereby increasing the risk of severe adverse effects (e.g., infections, malignancies, haematological complications). Therefore, it is extremely important for clinicians involved in renal transplantation to know the potential side effects of monoclonal antibodies in order to plan a correct therapeutic strategy minimizing/avoiding the onset and development of severe clinical complications.

Unexpected hematologic effects of biotherapeutics in nonclinical species and in humans

Biotherapeutics are expanding the arsenal of therapeutics available for treating and preventing disease. Although initially thought to have limited side effects due to the specificity of their binding, these drugs have now been shown to have potential for adverse drug reactions including effects on peripheral blood cell counts or function. Hematotoxicity caused by a biotherapeutic can be directly related to the activity of the biotherapeutic or can be indirect and due to autoimmunity, biological cascades, antidrug antibodies, or other immune system responses. Biotherapeutics can cause hematotoxicity primarily as a result of cellular activation, cytotoxicity, drug-dependent and independent immune responses, and sequelae from initiating cytokine and complement cascades.  The underlying pathogenesis of biotherapeutic-induced hematotoxicity often is poorly understood. Nonclinical studies have generally predicted clinical hematotoxicity for recombinant cytokines and growth factors.  However, most hematologic liabilities of biotherapeutics are not based on drug class but are species specific, immune-mediated, and of low incidence. Despite the potential for unexpected hematologic toxicity, the risk-benefit profile of most biotherapeutics is favorable; hematologic effects are readily monitorable and managed by dose modification, drug withdrawal, and/or therapeutic intervention.  This article reviews examples of biotherapeutics that have unexpected hematotoxicity in nonclinical or clinical studies. 

Adverse events to monoclonal antibodies used for cancer therapy: Focus on hypersensitivity responses

Fifteen monoclonal antibodies (mAbs) are currently registered and approved for the treatment of a range of different cancers. These mAbs are specific for a limited number of targets (9 in all). Four of these molecules are indeed directed against the B-lymphocyte antigen CD20; 3 against human epidermal growth factor receptor 2 (HER2 or ErbB2), 2 against the epidermal growth factor receptor (EGFR), and 1 each against epithelial cell adhesion molecule (EpCAM), CD30, CD52, vascular endothelial growth factor (VEGF), tumor necrosis factor (ligand) superfamily, member 11 (TNFSF11, best known as RANKL), and cytotoxic T lymphocyte-associated protein 4 (CTLA4). Collectively, the mAbs provoke a wide variety of systemic and cutaneous adverse events including the full range of true hypersensitivities: Type I immediate reactions (anaphylaxis, urticaria); Type II reactions (immune thrombocytopenia, neutopenia, hemolytic anemia); Type III responses (vasculitis, serum sickness; some pulmonary adverse events); and Type IV delayed mucocutaneous reactions as well as infusion reactions/cytokine release syndrome (IRs/CRS), tumor lysis syndrome (TLS), progressive multifocal leukoencephalopathy (PML) and cardiac events. Although the term "hypersensitivity" is widely used, no common definition has been adopted within and between disciplines and the requirement of an immunological basis for a true hypersensitivity reaction is sometimes overlooked. Consequently, some drug-induced adverse events are sometimes incorrectly described as "hypersensitivities" while others that should be described are not.

Approach to the diagnosis and management of drug-induced immune thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) is a challenging clinical problem that is under-recognized, difficult to diagnose and associated with severe bleeding complications. DITP may be caused by classic drug-dependent platelet antibodies (eg, quinine); haptens (eg, penicillin); fiban-dependent antibodies (eg, tirofiban); monoclonal antibodies (eg, abciximab); autoantibody formation (eg, gold); and immune complex formation (eg, heparin). A thorough clinical history is essential in establishing the diagnosis of DITP and should include exposures to prescription medications, herbal preparations and even certain foods and beverages. Clinical and laboratory criteria have been established to determine the likelihood of a drug being the cause of thrombocytopenia, but these criteria can only be applied retrospectively. The most commonly implicated drugs include quinine, quinidine, trimethoprim/sulfamethoxazole and vancomycin. We propose a practical approach to the diagnosis of the patient with suspected DITP. Key features are: the presence of severe thrombocytopenia (platelet nadir <20×10(9)/L); bleeding complications; onset 5 to 10days after first drug exposure, or within hours of subsequent exposures or after first exposure to fibans or abciximab; and exposure to drugs that have been previously implicated in DITP reactions. Treatment involves stopping the drug(s), administering platelet transfusions or other therapies if bleeding is present and counselling on future drug avoidance. The diagnosis can be confirmed by a positive drug re-challenge, which is often impractical, or by demonstrating drug-dependent platelet reactive antibodies in vitro. Current test methods, which are mostly flow cytometry-based, must show drug-dependence, immunoglobulin binding, platelet specificity and ideally should be reproducible across laboratories. Improved standardization and accessibility of laboratory testing should be a focus of future research.

Rituximab in renal transplantation

Rituximab is a chimeric anti-CD20 monoclonal antibody that leads to B cell depletion. It is not licensed for use in renal transplantation but is in widespread use in ABO blood group incompatible transplantation. It is an effective treatment for post-transplant lymphoproliferative disorder, and is also used in both HLA antibody incompatible renal transplantation and the treatment of acute rejection. Recent evidence suggests rituximab may prevent the development of chronic antibody mediated rejection. The mechanisms underlying its effects are likely to relate both to long-term effects on plasma cell development and to the impact on B cell modulation of T cell responses. Rituximab (in multiple doses or in combination with other monoclonal antibodies and/or other immunosuppressants) may lead to an increase in infectious complications, although the evidence is not clear. Rarely, the drug can cause a cytokine release syndrome, thrombocytopenia and neutropenia. It has been related to an increased risk of progressive multifocal leucoencephalopathy and, recently, deaths from cardiovascular causes. Trials examining the effects of rituximab in induction therapy for compatible renal transplantation and the treatment of chronic antibody mediated rejection are ongoing. These trials should aid greater understanding of the role of B-cells in the alloresponse to renal transplantation.

Rituximab and dexamethasone vs dexamethasone monotherapy in newly diagnosed patients with primary immune thrombocytopenia

In this study, we report the results from the largest cohort to date of newly diagnosed adult immune thrombocytopenia patients randomized to treatment with dexamethasone alone or in combination with rituximab. Eligible were patients with platelet counts ≤25×10(9)/L or ≤50×10(9)/L with bleeding symptoms. A total of 133 patients were randomly assigned to either dexamethasone 40 mg/day for 4 days (n = 71) or in combination with rituximab 375 mg/m(2) weekly for 4 weeks (n = 62). Patients were allowed supplemental dexamethasone every 1 to 4 weeks for up to 6 cycles. Our primary end point, sustained response (ie, platelets ≥50×10(9)/L) at 6 months follow-up, was reached in 58% of patients in the rituximab + dexamethasone group vs 37% in the dexamethasone group (P = .02). The median follow-up time was 922 days. We found longer time to relapse (P = .03) and longer time to rescue treatment (P = .007) in the rituximab + dexamethasone group. There was an increased incidence of grade 3 to 4 adverse events in the rituximab + dexamethasone group (P = .04). In conclusion, rituximab + dexamethasone induced higher response rates and longer time to relapse than dexamethasone alone. This study is registered at http://clinicaltrials.gov as NCT00909077.

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.

The effect of rituximab on humoral and cell mediated immunity and infection in the treatment of autoimmune diseases

Depletion of B lymphocytes using the anti-CD20 monoclonal antibody rituximab has wide-spread use in the treatment of patients with autoimmune disorders. As haematopoietic progenitor cells and only a fraction of differentiated plasma express CD20, the effect of rituximab on immune function appears to be minimal. However, hypogammagobulinaemia can occur with repeated doses and emerging data from large studies suggest a subtle increase in the risk of infection. Reactivation of latent JC virus, resulting in progressive multifocal leucoencephalopathy, and hepatitis B virus, resulting in hepatoxicity, have been documented in patients receiving rituximab; although confounding effects of concomitant immunosuppressive therapies and immune dysregulation due to the underlying disease make causal associations of infections problematic. This review discusses the efficacy of B cell depletion therapy in the treatment of autoimmune diseases, the effect of B cell depletion on infection and immunity including the role of the B cell in autoimmunity, and identifies areas of controversy.

Immune thrombocytopenia in lymphoproliferative disorders

Lymphoproliferative disorders are recognized as a common cause of secondary immune thrombocytopenia (ITP). The mechanisms involved in the pathogenesis of ITP associated with lymphoproliferative disorders are heterogeneous and often linked to the presence and activity of the malignant clone. A better understanding of the responsible mechanisms leading to ITP in each disease may allow for targeted treatment decisions, avoiding unwarranted immunosuppression and bleeding complications.

The late adverse events of rituximab therapy--rare but there!

Rituximab, an anti CD20 monoclonal antibody, has now become a cornerstone in the treatment of many CD20 positive hematological malignancies and a variety of autoimmune disorders. In contrast to the acute allergic and cytokine associated reactions, late adverse events of rituximab are indeed uncommon but at the same time probably under-reported. In this review, we detail late adverse events reported since its use in hemato-oncological neoplasias and other disorders. These adverse events include the development of late-onset neutropenia, defects of immune reconstitution with associated immune compromise, infections, progressive multifocal leukoencephalopathy, reactivation of hepatitis, intestinal perforation and interstitial pneumonitis. Possible mechanisms involved in rituximab-associated complications and the pathogenesis of these adverse effects are reviewed and discussed. Evidence based graded recommendations for the management of these adverse effects are proposed.