Rituximab in non-haematological disorders of adults and its mode of action

Risk of severe infection associated with immunoglobulin deficiency under rituximab therapy in immune-mediated inflammatory disease

OBJECTIVES

We evaluated the risk of severe infection in patients with immune-mediated inflammatory disease (IMID) treated with RTX and with Ig deficiency.

METHODS

This was an observational, retrospective single-centre study of patients undergoing treatment with at least one rituximab (RTX) infusion for an IMID until 31 May 2020. Patients were followed up for at least 12 months after the last infusion or until severe infection or death. Ig deficiency was classified as prevalent (before RTX) or acquired (normal Ig assay results before RTX but Ig deficiency during a follow-up).

RESULTS

Of 311 patients, 10.6% had prevalent and 19.6% acquired Ig deficiency. Prevalent Ig deficiency was related to concomitant treatment with glucocorticoids (GCs), in particular with a high daily dose at baseline; and acquired Ig deficiency to cumulative dose of RTX, mean Disease Activity Score in 28 joints (DAS28), immunosuppressor or GCs therapy at baseline, diabetes mellitus and obesity. Overall, 14.5% of patients had a severe infection during follow-up, which was numerically but not statistically more frequent in patients with prevalent Ig deficiency than normal Ig level. On multivariate analysis, risk of severe infection was associated with chronic pulmonary disease, GCs dose and mean DAS28-C reactive protein. In a time-dependent analysis, risk of severe infection was not associated with Ig deficiency, either acquired or prevalent (adjusted HR 1.04 (95% CI 0.5 to 2.3), p=0.92).

CONCLUSION

Risk of severe infection was not associated with RTX-induced Ig deficiency in patients with an IMID. RTX management should be discussed according to an individual assessment of the infectious risk, especially in patients with GC therapy or chronic lung disease.

Current Treatment Approach, Emerging Therapies and New Horizons in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE), the prototype of systemic autoimmune diseases is characterized by extreme heterogeneity with a variable clinical course. Renal involvement may be observed and affects the outcome. Hydroxychloroquine should be administered to every lupus patient irrespective of organ involvement. Conventional immunosuppressive therapy includes corticosteroids, methotrexate, cyclophosphamide, mycophenolate mofetil, azathioprine, cyclosporine and tacrolimus. However, despite conventional immunosuppressive treatment, flares occur and broad immunosuppression is accompanied by multiple side effects. Flare occurrence, target organ involvement, side effects of broad immunosuppression and increased knowledge of the pathogenetic mechanisms involved in SLE pathogenesis as well as the availability of biologic agents has led to the application of biologic agents in SLE management. Biologic agents targeting various pathogenetic paths have been applied. B cell targeting agents have been used successfully. Belimumab, a B cell targeting agent, has been approved for the treatment of SLE. Rituximab, an anti-CD20 targeting agent is also used in SLE. Anifrolumab, an interferon I receptor-targeting agent has beneficial effects on SLE. In conclusion, biologic treatment is applied in SLE and should be further evaluated with the aim of a good treatment response and a significant improvement in quality of life.

Fever of Unknown Origin, a Vascular Event, and Immunosuppression in Tick-Endemic Areas: Think About Neoehrlichiosis

Three patients were referred to our hospital because of fever of unknown origin (FUO) and thrombosis or thrombophlebitis. All of them had been under immunosuppression (IS) with rituximab. Intensive diagnostics for FUO and blood cultures remained negative. Finally, the association of fever, immunosuppression, and a vascular event led to the suspicion of Candidatus Neoehrlichia mikurensis (CNM) infection. The diagnosis was confirmed by species-specific polymerase chain reaction (PCR) in the peripheral blood. Therapy with doxycycline or rifampicin led to the resolution of the disease. A liver biopsy was performed in one patient due to hepatomegaly and elevated liver enzymes demonstrating hemophagocytosis. To our knowledge, this is the first histopathological study of liver tissue in CNM infection. The evidence of hemophagocytosis raises the question of whether symptomatic CNM infection might be in part related to host inflammatory and immune responses.

Bullous systemic lupus erythematosus in females

Bullous systemic lupus erythematosus (BSLE) is a rare blistering presentation of systemic lupus erythematosus, typically affecting women with the highest incidence in those of African descent. The key pathogenic insult includes the formation of autoantibodies against type VII collagen, which weaken the basement membrane zone and lead to the formation of subepidermal blisters. The acute vesiculobullous eruptions in BSLE generally tend to affect photo-distributed areas, although they can arise unrelated to sun exposure (eg, mucous membranes, axillae). The bullae can arise from erythematous macules, inflammatory plaques, or previously normal skin. Their appearance can range from small, grouped vesicles reminiscent of lesions in dermatitis herpetiformis to large, tense blisters, similar to bullous pemphigoid. Internal organ involvement occurs in up to 90% of those affected. This mostly includes lupus nephritis (classes III–V, lifetime prevalence of up to 90%), arthralgias/arthritis, and cytopenias, while serositis and neuropsychiatric involvement are rare. First-line management with dapsone should be considered in mild disease with stable underlying systemic lupus erythematosus. As discussed in this review, the off-label use of rituximab (an anti-CD20 B-cell depleting agent) has been shown to be safe and effective in several refractory cases of BSLE unresponsive to dapsone, glucocorticoids, or steroid-sparing immunosuppressants.

Quick preparation of ABO-incompatible living donor liver transplantation for acute liver failure

Acute liver failure is life-threatening and has to be treated by liver transplantation urgently. When deceased donors or ABO-compatible living donors are not available, ABO-incompatible (ABO-I) living donor liver transplantation (LDLT) becomes the only choice. How to prepare ABO-I LDLT urgently is an unsolved issue. A quick preparation regimen was designed, which was consisted of bortezomib (3.5mg) injection to deplete plasma cells and plasma exchange to achieve isoagglutinin titer ≤ 1: 64 just prior to liver transplantation and followed by rituximab (375mg/m² ) on post-operative day one to deplete B-cells. Eight patients received this quick preparation regimen to undergo ABO-I LDLT for acute liver failure from 2012 to 2019. They aged between 50 and 60 years. The median MELD score was 39 with a range from 35 to 48. It took 4.75 ± 1.58 days to prepare such an urgent ABO-I LDLT. All the patients had successful liver transplantations, but one patient died of antibody-mediated rejection at post-operative month 6. The 3-month, 6-month, and 1-year graft/patient survival were 100%, 87.5%, and 75%, respectively. In conclusion, this quick preparation regimen can reduce isoagglutinin titers quickly and make timely ABO-I LDLT feasible for acute liver failure. This article is protected by copyright. All rights reserved.

Presence of onconeural antibodies in sarcoidosis patients with parasarcoidosis syndrome

Background

Bothersome symptoms from sarcoidosis can develop in the absence of identified granulomas. These parasarcoidosis complaints can include small fiber neuropathy, diaphoresis, dysautonomia, and fatigue. Similar issues are also encountered in some cancer patients, especially those with onconeural antibodies.

Methods

Serum was obtained for onconeural antibody testing from sarcoidosis patients with parasarcoidosis symptoms seen at the University of Cincinnati Sarcoidosis clinic during a six month period. Detection of antibodies was performed using an onconeural antibody panel.

Results

A total of 268 patients with sarcoidosis and one or more features suggesting parasarcoidosis symptoms were enrolled in the study. Of these, 60 (22.4%) had one or more positive onconeural antibodies. In a control group of 46 non sarcoidosis patients seen in the interstitial lung disease clinic, there were only three patients with a positive antibody (Chi square=6.143, p=0.0132). A subgroup of sarcoidosis and control patients completed the small fiber neuropathy screening list. Sarcoidosis patients had a significantly higher score than the control patients (sarcoidosis: 7 [0-49] (Median [range] versus non sarcoidosis: 3 [0-31], p=0.0074). However, no significant differences were measured in the SFNL scores for sarcoidosis patients with an onconeural antibody (9 [3-36]) versus without (7 [0-49]).

Conclusion

In patients with parasarcoidosis symptoms, approximately 30% have evidence of onconeural antibody production. This may be a potential cause for parasarcoidosis symptoms in some patients.

Pneumocystis pneumonia versus rituximab-induced interstitial lung disease in lymphoma patients receiving rituximab-containing chemotherapy

It is difficult to differentiate Pneumocystis pneumonia (PCP) from rituximab-induced interstitial lung disease (RILD) in lymphoma patients with diffuse pulmonary infiltrates who are receiving rituximab-containing chemotherapy. Using a clinical scoring system, we aim to differentiate PCP from RILD who are receiving rituximab-containing chemotherapy. We reviewed the medical records of lymphoma patients who had received rituximab-containing chemotherapy between 2012 and 2015 in a tertiary hospital. Among 613 lymphoma patients receiving rituximab-containing chemotherapy, 97 (16%) had diffuse pulmonary infiltrates. Of these, 16 (16%) with an alternative diagnosis and 22 (23%) with an indeterminate diagnosis were excluded. Finally, 21 (22%) patients were classified as having PCP and the remaining 38 (39%) as having RILD. Fever, short duration of symptoms (≤5 days), systemic inflammatory response syndrome (SIRS), and severe extent of disease on CT scan (>75%) were more common in patients with PCP than in those with RILD. Clinical scores were determined using the following system: SIRS = score 1, symptom duration ≤5 days = score 1, extent of disease on CT >75% = score 4. A score of ≥2 differentiated PCP from RILD with 91% sensitivity (95% CI, 70-99) and 71% specificity (95% CI, 54-84). A clinical scoring system based on presence of SIRS, short duration of symptoms, and severe extent of disease on CT scan appears to be useful in differentiation of PCP from RILD.

Rituximab in pemphigus

Pemphigus is a severe autoimmune blistering disease mediated by pathogenic anti-desmoglein antibodies leading to an inter keratinocyte disjunction. Rituximab is a monoclonal antibody that binds to the CD-20 antigen of B lymphocytes, which causes B-cell depletion and a subsequent reduction in pathogenic autoantibodies. Its therapeutic role in pemphigus has been progressively growing with increasing evidence of successful outcomes. Rituximab was initially off-labeled used as an alternative in patients with recalcitrant or relapsing pemphigus and in patients with contraindications to systemic corticosteroids. Recently, a large randomized clinical trial has shown that first-line use of rituximab combined with short-term prednisone regimen was both more effective and potentially safer than a standard regimen of high doses of corticosteroids in patients with moderate to severe pemphigus.

Refractory myasthenia gravis - clinical profile, comorbidities and response to rituximab

Introduction: Myasthenia gravis (MG) is an antibody mediated autoimmune neuromuscular disorder characterized by fatigable muscle weakness. A proportion of myasthenia gravis patients are classified as refractory due to non responsiveness to conventional treatment. This retrospective study was done to evaluate clinical profile, epidemiological, laboratory, and features of patients with MG and mode of management using rituximab and complications. Methods: Data of myasthenia gravis patients admitted or presented to outpatient department (previous medical records) with MG between January 2008 and January 2016 were included. A total of 512 patients fulfilled the clinical and diagnostic criteria of myasthenia gravis of which 76 patients met the diagnostic certainty for refractory myasthenia gravis and were evaluated. Results: Out of 76 refractory MG patients, 53 (69.73%) patients fulfilled all the three defined criteria. The median age of onset of the refractory MG group was 36 years with a range of 27-53 years. In our study 25 patients (32.89%) belonged to the age group of 21-30 years. Anti-MuSK antibodies were positive in 8 non-refractory MG patients (2.06%) and 36 refractory MG patients (47.36%). Mean HbA_1C was found to be 8.6±2.33. The dose of administered prednisone decreased by a mean of 59.7% (p=3.3x10^-8) to 94.6% (p=2.2x10^-14) after the third cycle of rituximab treatment. Conclusion: The refractory MG patients are most commonly female with an early age of onset, anti-MuSK antibodies, and thymomas. Refractory MG patients have higher prevalence and poor control (HbA_1C >8%) of diabetes mellitus and dyslipidemia probably due to increased steroid usage. Rituximab is very efficient in treatment of refractory MG with adverse effects being low.

Rituximab use in adult primary glomerulopathy: where is the evidence?

Rituximab is a chimeric anti-CD20 antibody that results in depletion of B-cell lymphocytes. It is currently used in the treatment of a variety of autoimmune diseases, in addition to CD20-positive lymphomas. The use of rituximab in the treatment of the adult primary glomerular diseases has emerged recently, although not yet established as first-line therapy in international guidelines. In patients with steroid-dependent minimal change disease or frequently relapsing disease, and in patients with idiopathic membranous nephropathy (IMN), several retrospective and prospective studies support the use of rituximab to induce remission, whereas in idiopathic focal and segmental glomerulosclerosis (FSGS), the use of rituximab has resulted in variable results. Evidence is still lacking for the use of rituximab in patients with immunoglobulin A nephropathy (IgAN) and idiopathic membranoproliferative glomerulonephritis (MPGN), as only few reports used rituximab in these two entities. Randomized controlled trials (RCTs) are warranted and clearly needed to establish the definitive role of rituximab in the management of steroid-dependent and frequently relapsing minimal change disease, IMN, both as first-line and second-line treatment, and in MPGN. We await the results of an ongoing RCT of rituximab use in IgAN. Although current evidence for the use of rituximab in patients with idiopathic FSGS is poor, more RCTs are needed to clarify its role, if any, in the management of steroid-resistant or steroid-dependent FSGS.

Current and emerging treatment options for interstitial lung disease in patients with rheumatic disease

The management of connective tissue disease-associated interstitial lung disease (CTD-ILD) is complex and this arena offers many challenges to the practicing clinician. Unfortunately, treatment strategies and recommendations are often based on experience rather than evidence, and there are few effective therapeutic options. Pharmacologic intervention with immunosuppression is usually the mainstay of therapy and is reserved for those with clinically significant and/or progressive ILD. There is a desperate need for controlled trials across the spectrum of CTD-ILD and a number of potentially promising novel therapies warrant further study. It is important to address co-morbid conditions or aggravating factors (e.g., gastroesophageal reflux, aspiration, bone health, pulmonary hypertension, Pneumocystis jiroveci prophylaxis) and to institute non-pharmacologic management strategies (e.g., supplemental oxygen and cardiopulmonary rehabilitation) as part of a comprehensive treatment plan in CTD-ILD.

Adult Living Donor Liver Transplantation Across ABO-Incompatibility

The objective of this study was to evaluate the results of adult ABO-incompatible living donor liver transplantation (LDLT).ABO-incompatible LDLT is an aggressive treatment that crosses the blood-typing barrier for saving lives from liver diseases. Although graft and patient survival have been improved recently by various treatments, the results of adult ABO-incompatible LDLT require further evaluation.Two regimens were designed based on isoagglutinin IgG and IgM titers and the time course of immunological reactions at this institute. When isoagglutinin IgG and IgM titers were ≤64, liver transplantation was directly performed and rituximab (375 mg/m) was administrated on postoperative day 1 (regimen I). When isoagglutinin titers were >64, rituximab (375 mg/m) was administered preoperatively with or without plasmapheresis and boosted on postoperative day 1 (regimen II). Immunosuppression was achieved by administration of mycophenolate mofetil, tacrolimus, and steroids.Forty-six adult ABO-incompatible and 340 ABO-compatible LDLTs were performed from 2006 to 2013. The Model for End-Stage Liver Disease scores for ABO-incompatible recipients ranged from 7 to 40, with a median of 14. The graft-to-recipient weight ratio ranged from 0.61% to 1.61% with a median of 0.91%. The 1-, 3-, and 5-year survival rates were 81.7%, 75.7%, and 71.0%, respectively, for ABO-incompatible LDLT recipients, compared to 81.0%, 75.2%, and 71.5% for ABO-C recipients (P = 0.912). The biliary complication rate was higher in ABO-incompatible LDLT recipients than in the ABO-compatible recipients (50.0% vs 29.7%, P = 0.009).In the rituximab era, the blood type barrier can be crossed to achieve adult ABO-incompatible LDLT with survival rates comparable to those of ABO-compatible LDLT, but with more biliary complications.

Rituximab Induced Interstitial Lung Disease in Patients with Non-Hodgkin’s Lymphoma: A Clinical Study of Six Cases and Review of the Literature

Background. Rituximab-induced lung disease (R-ILD) is a rare entity that should be considered in patients treated with rituximab who present with dyspnea, fever, and cough but no clear evidence of infection. Aim. The aim of this prospective longitudinal study is to describe the clinical presentation, management, and response to rechallenge in patients diagnosed with rituximab induced ILD over a period of one year. Results. Out of sixteen patients with CD20 positive non-Hodgkin’s lymphoma who received rituximab along with standard chemotherapy, six patients developed features suggestive of R-ILD. Four (66.6%) of these patients had diffuse large B cell lymphoma. The median time of presentation of R-ILD was after the 3rd cycle of chemotherapy. Three patients (50%) presented with acute onset of high fever, dyspnea, and dry cough while the remaining three presented with insidious onset of dyspnea and dry cough. An infectious etiology for the respiratory illness was ruled out in all patients with an exhaustive work-up. Four patients (66.6%) responded to corticosteroid treatment and supplemental oxygen. One patient required mechanical ventilation and succumbed to ILD while another required prolonged supplemental oxygen. Two (33.3%) of patients were successfully rechallenged with rituximab under cover of corticosteroids. Conclusions. Rituximab induced lung disease is a rare but potentially fatal pulmonary toxicity which requires a high index of suspicion for early diagnosis and treatment.

Subcutaneous immunoglobulin in lymphoproliferative disorders and rituximab-related secondary hypogammaglobulinemia: a single-center experience in 61 patients

Intravenous immunoglobulin replacement therapy represents the standard treatment for hypogammaglobulinemia secondary to B-cell lymphoproliferative disorders. Subcutaneous immunoglobulin infusion is an effective, safe and well-tolerated treatment approach in primary immunodeficiencies but no extensive data are available on their use in secondary hypogammaglobulinemia, a frequent phenomenon occurring after treatment with anti-CD20 monoclonal antibodies in lymphoproliferative disorders. In this retrospective study we evaluated efficacy (serum IgG trough levels, incidence of infections per year, need for antibiotics) and safety (number of adverse events) of intravenous (300 mg/kg/4 weeks) versus subcutaneous (75 mg/kg/week) immunoglobulin replacement therapy in 61 patients. In addition, the impact of the infusion methods on quality of life was compared. All patients were treated with subcutaneous immunoglobulin, and 33 out of them had been previously treated with intravenous immunoglobulin. Both treatments appeared to be effective in replacing Ig production deficiency and in reducing the incidence of infectious events and the need for antibiotics. Subcutaneous immunoglobulin obtained a superior benefit when compared to intravenous immunoglobulin achieving higher IgG trough levels, lower incidence of overall infection and need for antibiotics. The incidence of serious bacterial infections was similar with both infusion ways. As expected, a lower number of adverse events was registered with subcutaneous immunoglobulin, compared to intravenous immunoglobulin, with no serious adverse events. Finally, we observed an improvement in health-related quality of life parameters after the switch to subcutaneous immunoglobulin. Our results suggest that subcutaneous immunoglobulin is safe and effective in patients with hypogammaglobulinemia associated to lymphoproliferative disorders.

Prospective data collection of off-label use of rituximab in Australian public hospitals

BACKGROUND

Rituximab is a chimeric, anti-CD20 monoclonal antibody registered for the treatment of B-cell malignancies and refractory rheumatoid arthritis in Australia. In addition to these approved indications, there has been growing interest in the use of off-label rituximab in the management of a variety of diseases.

AIMS

To determine the current usage of off-label rituximab in Australia, we collected nationwide data.

METHODS

Information regarding patients receiving rituximab for off-label indications was prospectively collected for a 6-month period from Australian public hospitals. Data recorded included clinical indication, dosing schedule, previous therapy and efficacy assessment. The level of evidence for the use of rituximab was determined for each off-label indication.

RESULTS

During the 6-month period, a total of 364 instances of off-label rituximab use was recorded in the national database. A total of 63 underlying diagnoses was identified. These were subclassified into haematological disorders (19%), autoimmune connective tissue diseases (12%), vasculitis (12%), neurological disorders (12%), transplant-related uses (12%), haematological malignancies (11%), muscle disorders (8%), renal diseases (6%), dermatological conditions (5%), other conditions (2%) and ocular diseases (1%). Forty percent of these requests were supported only by level 4 evidence of benefit. Data highlighted the non-standardised approaches to drug approval mechanisms, dosing schedules and monitoring for efficacy.

CONCLUSIONS

Off-label rituximab is prescribed for a diverse range of clinical conditions. Determining a safe and effective means of regulating this use within an evidence-based framework remains an ongoing challenge.

Stability of stock and diluted rituximab

PURPOSE

The stability of two rituximab preparations stored in polyvinyl chloride (PVC) bags at 4 °C for up to 14 days was investigated.

METHODS

Two types of test samples were prepared: (1) 10 mL of rituximab solution (10 mg/mL) drawn directly from the original manufacturer's vial and injected into sterile glass vials and (2) 3 mL of rituximab 10 mg/mL mixed with 17 mL of 0.9% sodium chloride injection and injected into sterile PVC bags. Samples were analyzed immediately after preparation and after storage at 4 °C for 3, 7, and 14 days. Rituximab activity at the designated time points was measured using a validated enzyme-linked immunosorbent assay (ELISA) method. Chemical stability was defined as the retention of ≥85% of the drug's initial activity. Physical stability was evaluated through visual inspection for color changes or precipitate formation under normal laboratory lighting.

RESULTS

The results of ELISA testing (with spectrophotometric absorbance assessment) indicated that the percentage of initial rituximab activity retained was over 85% for both test preparations under the storage conditions evaluated; no changes in color or turbidity were observed in any of the test samples. These findings suggest that extending the expiration dating of both stock and diluted rituximab solutions beyond the manufacturer-specified limit of 24 hours is feasible.

CONCLUSION

Rituximab 10 mg/mL undiluted in glass vials and 1.5 mg/mL diluted in 0.9% sodium chloride injection in PVC bags are stable at 4 °C for up to 14 days.

Primary renal lymphoma: long-term results of two patients treated with a chemotherapy + rituximab protocol

Primary renal lymphoma (PRL) is a rare disease of which the etiology and pathogenesis remain controversial, and there is currently no standard treatment for it. We present the results of a long-term followup of two patients who were diagnosed with PRL and treated with cyclophosphamide, adriamycin, vincristine, prednisolone and rituximab (CHOP + R) regimen. Both patients reached a complete response, and there is no evidence of recurrence after 4.5- and 5-year followup periods. Based on our experience and other recently published studies, we recommend the combination of CHOP + rituximab as the elective treatment for this disease. To our knowledge, this is the longest followup period with a complete response that has been reported with this modality of treatment.

Rituximab and its use in autoimmune bullous disorders

Rituximab is a chimeric, murine-human, monoclonal antibody against the CD20 antigen of B lymphocytes. It has been used off-label to treat and manage autoimmune and dermatologic diseases as an alternative or adjuvant therapy to systemic treatments. Due to cost, potential complications, and lack of data rituximab is used after standard systemic therapies have failed or the patient is absolutely contraindicated for corticosteroids. More research is required.

Response of patients with refractory myasthenia gravis to rituximab: a retrospective study

INTRODUCTION

Myasthenia gravis, an autoimmune disorder of neuromuscular transmission, is treated by an array of immunomodulating therapies. A variable response is observed with certain patients being medically refractory.

METHODS

We report the results of 14 refractory generalized myasthenia gravis patients (6 AChR+; 8 MuSK+) treated with rituximab.

RESULTS

Sustained clinical improvement was observed in all patients as well as a reduction of conventional immunotherapies. Prednisone dose decreased a mean of 65.1%, 85.7%, and 93.8% after cycle 1, 2, and 3 of rituximab therapy, respectively. A statistically significant reduction in plasma exchange sessions was seen after cycle 1 with all patients being off of plasma exchange after cycle 3. Acetylcholine receptor antibody titers decreased a mean of 52.1% (p = 0.0046) post-cycle 2.

CONCLUSION

Our results support the hypothesis that rituximab is beneficial and well tolerated in managing refractory myasthenia gravis and nearly doubles published cases. We propose that B-cell-directed therapies may become an attractive option and suggest pursuit of a prospective trial.

Innovative uses of rituximab in dermatology

Since its approval in 1997 by the US Food and Drug Administration, rituximab has been approved for use in certain B-cell lymphomas and treatment-resistant rheumatoid arthritis. Over the past 10 years, many published reports have suggested rituximab's efficacy in several inflammatory conditions in dermatology. This article includes a review of the mechanism of action, dosing, side-effect profile, and the current literature for various off-label uses of this CD20+ B-cell antagonist, rituximab.

Rituximab-associated neutropenia

Several recent studies have reported the phenomenon of late-onset neutropenia occurring usually several months following the administration of rituximab or rituximab-based therapies. While it appears that late-onset neutropenia is usually not clinically significant and is self-limited, it is important to recognize its existence given the expanding use of rituximab in both hematologic and nonhematologic disorders. Late-onset neutropenia is intriguing biologically and while its pathogenesis and mechanism are not completely understood, many interesting hypotheses have been proposed to explain its occurrence.

Rituximab pharmacokinetics during the management of acute idiopathic thrombotic thrombocytopenic purpura

BACKGROUND

Increasingly, patients with acute, idiopathic, antibody mediated thrombotic thrombocytopenic purpura (TTP) are being treated with rituximab to achieve a durable remission, however, there is the potential that it is removed by plasma exchange (PEX).

OBJECTIVES

To look at the pharmacokinetics and pharmacodynamics of rituximab in patients with acute idiopathic TTP undergoing PEX.

PATIENTS AND METHODS

Patients who received rituximab for acute idiopathic TTP (group 1, n = 30) and a control group (group 2, n = 3) of TTP patients in remission receiving rituximab electively as maintenance were included. Rituximab levels were measured before/after each infusion, before/after PEX and in follow-up. ADAMTS-13 activity, anti-ADAMTS-13 IgG and CD19% were measured to assess response.

RESULTS

The median number of PEX to remission after rituximab was 10 (range 4-25). In group 1 there was no significant incremental rise in the peak serum rituximab level until dose 4. Trough levels were lower in patients who had had PEX since their last rituximab infusion. In the control group, there was an incremental rise in the peak serum rituximab level and all patients had detectable trough levels. The median fall in rituximab per PEX was 65%. All patients achieved CD19 < 1%. In group 1, the median time to undetectable rituximab was 5 months (range 0-12 months) and to B cell return was 7 months (range 3-24 months). ADAMTS-13 increased and anti-ADAMTS-13 fell after therapy. There were three deaths and two relapses in group 1. Relapse was not temporally related to B cell return.

Safety and efficacy of rituximab in patients with hepatitis C virus-related mixed cryoglobulinemia and severe liver disease

The effectiveness of rituximab in hepatitis C virus (HCV)-related mixed cryoglobulinemia (MC) has been shown. However, the risk of an increase in viral replication limits its use in cirrhosis, a condition frequently observed in patients with MC. In this prospective study, 19 HCV-positive patients with MC and advanced liver disease, who were excluded from antiviral therapy, were treated with rituximab and followed for 6 months. MC symptoms included purpura, arthralgias, weakness, sensory-motor polyneuropathy, nephropathy, and leg ulcers. Liver cirrhosis was observed in 15 of 19 patients, with ascitic decompensation in 6 cases. A consistent improvement in MC syndrome was evident at the end-of-treatment (EOT) and end-of-follow-up (EOF-U). Variable modifications in both mean viral titers and alanine aminotransferase values were observed at admission, EOT, third month of follow-up, and EOF-U (2.62 x 10(6), 4.28 x 10(6), 4.82 x 10(6), and 2.02 x 10(6) IU/mL and 63.6, 49.1, 56.6, and 51.4 IU/L, respectively). Improvement in liver protidosynthetic activity and ascites degree was observed at EOT and EOF-U, especially in more advanced cases. This study shows the effectiveness and safety of rituximab in MC syndrome with advanced liver disease. Moreover, the depletion of CD20(+) B cells was also followed by cirrhosis syndrome improvement despite the possibility of transient increases of viremia titers.

Rituximab in the management of refractory myasthenia gravis

Myasthenia gravis (MG) is an immune-mediated disorder with a variable response to treatment. In this study, patients with refractory MG who were treated with rituximab were identified. A review of patients referred to the Yale Neuromuscular Clinic was performed. Patients with refractory MG who were treated with rituximab were reviewed for response to treatment. Patients who had muscle-specific kinase (MuSK(+)) or acetylcholine receptor (AChR(+)) antibodies were included. Six patients were identified who met the criteria described. All patients tolerated rituximab without side effects and had a reduced need for immunosuppressants and/or improvement in clinical function. Patients with refractory MG appeared to respond to rituximab in this small, retrospective study. This result suggests that a larger, prospective trial is indicated.

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.