Efficacy of low-dose rituximab for mixed cryoglobulinemia

Management of mixed cryoglobulinemia with rituximab: evidence and consensus-based recommendations from the Italian Study Group of Cryoglobulinemia (GISC)

Cryoglobulinemic vasculitis (CV) or mixed cryoglobulinemic syndrome (MCS) is a systemic small-vessel vasculitis characterized by the proliferation of B-cell clones producing pathogenic immune complexes, called cryoglobulins. It is often secondary to hepatitis C virus (HCV), autoimmune diseases, and hematological malignancies. CV usually has a mild benign clinical course, but severe organ damage and life-threatening manifestations can occur. Recently, evidence in favor of rituximab (RTX), an anti-CD 20 monoclonal antibody, is emerging in CV: nevertheless, questions upon the safety of this therapeutic approach, especially in HCV patients, are still being issued and universally accepted recommendations that can help physicians in MCS treatment are lacking. A Consensus Committee provided a prioritized list of research questions to perform a systematic literature review (SLR). A search was made in Medline, Embase, and Cochrane library, updated to August 2021. Of 1227 article abstracts evaluated, 27 studies were included in the SLR, of which one SLR, 4 RCTs, and 22 observational studies. Seventeen recommendations for the management of mixed cryoglobulinemia with rituximab from the Italian Study Group of Cryoglobulinemia (GISC) were developed to give a valuable tool to the physician approaching RTX treatment in CV.

Impact of direct acting antivirals on hepatitis c virus-related cryoglobulinemic syndrome

INTRODUCTION

Mixed cryoglobulinemia (MC) is a B-cell lymphoproliferative disorder largely attributable to HCV infection. MC clinical manifestations are determined by systemic vasculitis of low/medium sized vessels (mixed cryoglobulinemia syndrome or cryoglobulinemic vasculitis and CV) caused by the deposition of cryoglobulins in blood vessels.

EVIDENCE ACQUISITION

A systematic review was performed via the Medline and Scopus databases to evaluate studies concerning CV treatment with new direct antiviral agents (DAAs) and their effect on the syndrome.

EVIDENCE SYNTHESIS

The introduction of Interferon-free protocols has led to more evident positive effects than those observed in the treatment of C hepatitis/cirrhosis. In fact, IFN-free, DAA-based therapy minimised side effects permitting the treatment of previously contraindicated patients and led to a particularly high SVR rate and to a clinical/immunological response in the majority of patients, even if at different levels in different patients, from restitutio ad integrum to partial response. In view of the clearly positive evolution in CV management, the persistence of CV manifestations, in partial or non-responders continues to pose problems in the clinical approach to patients who represent a new condition that is still not completely known.

CONCLUSIONS

Results of DAAs-based therapy strongly confirm the use of anti-HCV therapy as the first-line therapeutic option in CV patients. However, growing evidence of a possible persistence or late relapse of CV suggests the need for longer/more accurate post-DAAs follow-ups as well as biomarkers that are capable of predicting the risk of clinical relapse/persistence to allow for the design of rational post-HCV eradication clinical flow-charts.

Cryoglobulinemic glomerulonephritis: clinical presentation and histological features, diagnostic pitfalls and controversies in the management. State of the art and the experience on a large monocentric cohort treated with B cell depletion therapy

Cryoglobulinemia is defined by the presence of immunoglobulins having the following characteristics: forming a gel when temperature is <37 °C, precipitate in a reversible manner in the serum, and redissolve after rewarming. The presence of both polyclonal IgG and monoclonal IgM (type II), or of polyclonal IgG and polyclonal IgM (type III) identifies the mixed cryoglobulinemia (MC). The identification of the Hepatitis C virus (HCV) infection in most of the cases previously defined as "essential" represented a cornerstone in the understanding the pathogenesis of this condition. The picture of MC comprehends heterogeneous clinical presentations: from arthralgias, mild palpable purpura, fatigue to severe vasculitis features with skin necrotic pattern, peripheral neuropathy and, less commonly, lungs, central nervous system, gastrointestinal tract, and heart involvement. The kidney represents the most common organ presentation, and the presence of glomerulonephritis is a key element when considering prognosis. We discuss the clinical presentation and histological features, diagnostic pitfalls, and controversies in the management of patients with cryoglobulinemic glomerulonephritis, with a special focus on reporting our experience in treating patients with B cell depletion therapy.

Recommendations for managing the manifestations of severe and life-threatening mixed cryoglobulinemia syndrome

OBJECTIVE

Some of the manifestations of mixed cryoglobulinemia syndrome (MCS) can be severe or life-threatening, and should be rapidly contained but, as the therapeutic approaches to such conditions are largely based on anecdotal data, a consensus conference was organised by the Italian Group for the Study of Cryoglobulinemia (GISC) with the aim of providing a set of recommendations based on an in-depth survey of the available data and expert opinion.

METHODS

The consensus panel, which included specialists working in different medical fields involved in the management of MCS patients, was first asked to divide the manifestations of MCS into severe or life-threatening conditions on the basis of their own experience, after which a complete literature review was carried out in accordance with the Cochrane guidelines for systematic reviews.

RESULTS

Therapeutic plasma exchange (TPE) was considered the elective first-line treatment in the case of life-threatening manifestations of MCS (LT-MCS) and patients with severe clinical symptoms (S-MCS) who fail to respond to (or who are ineligible for) other treatments. The data supporting the combined use of cyclophosphamide and TPE were considered limited and inconclusive. High-dose pulsed glucocorticoid (GCS) therapy can be considered the first-line treatment of severe MCS, generally in association with TPE. Rituximab (RTX)-based treatments should be considered in patients with skin ulcers, peripheral neuropathy or glomerulonephritis, and in patients with persistent LT-MCS after TPE. In patients with hepatitis C virus-related MCS with S-MCS, viral eradication should be attempted as soon as a patient's condition allows the use of direct-acting antivirals.

International therapeutic guidelines for patients with HCV-related extrahepatic disorders. A multidisciplinary expert statement

Hepatitis C virus (HCV) is both hepatotrophic and lymphotropic virus that causes liver as well extrahepatic manifestations including cryoglobulinemic vasculitis, the most frequent and studied condition, lymphoma, and neurologic, cardiovascular, endocrine-metabolic or renal diseases. HCV-extrahepatic manifestations (HCV-EHMs) may severely affect the overall prognosis, while viral eradication significantly reduces non-liver related deaths. Different clinical manifestations may coexist in the same patient. Due to the variety of HCV clinical manifestations, a multidisciplinary approach along with appropriate therapeutic strategies are required. In the era of interferon-free anti-HCV treatments, international recommendations for the therapeutic management of HCV-EHMs are needed. This implies the need to define the best criteria to use antivirals and/or other therapeutic approaches. The present recommendations, based on qualified expert experience and specific literature, will focus on etiological (antiviral) therapies and/or traditional pathogenetic treatments that still maintain their therapeutic utility.

Spotlight on rituximab in the treatment of antineutrophil cytoplasmic antibody-associated vasculitis: current perspectives

A 54-year-old patient presented to his general practitioner because of strong muscle pain in both thighs. Inflammatory parameters (CRP 16.3 mg/dL) and white blood cells (15 g/L) were elevated. The patient reported a weight loss of 10 kg in 4 weeks. There was no fever or any other specific symptoms. Urine dipstick examination and computed tomography of the chest were unremarkable. Because of increasing symptoms, the patient was referred to our department. Magnetic resonance tomography showed diffuse inflammatory changes of the muscles of both thighs. Neurological examination and electrophysiology revealed axonal sensorimotor neuropathy and ground-glass opacities of both lungs had occurred. Serum creatinine increased to 229 μmol/L within a few days, with proteinuria of 3.3 g/g creatinine. Kidney biopsy showed diffuse pauci-immune proliferative glomerulonephritis. Proteinase 3-specific antineutrophil cytoplasmic antibodies were markedly increased. Birmingham Vasculitis Activity Score was 35. Within 2 days, serum creatinine further increased to 495 μmol/L. Plasma exchange, high-dose glucocorticosteroids, and hemodialysis were started. The patient received cyclophosphamide 1 g twice and rituximab 375 mg/m² four times according to the RITUXVAS protocol. Despite ongoing therapy, hemodialysis could not be withdrawn and had to be continued over 3 weeks until diuresis normalized. Glucocorticosteroids were tapered to 20 mg after 2 months, and serum creatinine was 133 μmol/L. However, nephritic urinary sediment reappeared. Another dose of 1 g cyclophosphamide was given, and glucocorticosteroids were raised for another 4 weeks. After 6 months, the daily prednisolone dose was able to be tapered to 5 mg. Serum creatinine was 124 μmol/L, proteinuria further decreased to 382 mg/g creatinine, and the Birmingham Vasculitis Activity Score was 0. Maintenance therapy with rituximab 375 mg/m² every 6 months was started. At the last visit after 8 months, the patient was still in remission, with only minor persistent dysesthesia of the left foot and a persistent serum creatinine of 133 μmol/L.

Efficacy of low-dose rituximab for the treatment of mixed cryoglobulinemia vasculitis: Phase II clinical trial and systematic review

OBJECTIVE

To evaluate whether rituximab at a low dose of 250 mg/m(2) × 2 may be as effective as at higher dosages, most commonly 375 mg/m(2)×4, used in previous studies on the treatment of patients with refractory mixed cryoglobulinemia (MC) vasculitis associated with hepatitis C virus (HCV) infection.

METHODS

We conducted a phase 2, single-arm two-stage trial (EUDRACT n. 2008-000086-38) of low-dose rituximab in 52 patients with HCV-associated MC who were ineligible/intolerant or non-responder to antiviral therapy. The primary outcomes were response of vasculitis evaluated by the Birmingham Vasculitis Activity Score (BVAS) at months 3, 6 and 12, rate of relapses and time to relapse, and rate of adverse events. Our data were compared with those reported in 19 published studies selected among 291 reviewed in a literature search.

RESULTS

The cumulative response rate (complete and partial) at month 3 was 81% in our patients, and 86% in 208 patients from studies using high-dose rituximab. The relapse rate and median time to relapse were, respectively, 41% and 6 months in our study, and 32% and 7 months in high-dose studies. Treatment-related adverse events were 11.5% in our study and 19.9% in high-dose studies. None of these differences was statistically significant.

CONCLUSION

Rituximab at a low dosage of 250 mg/m(2) × 2 is as effective as at higher dosages for treating MC vasculitis. This low-dose regimen may improve the cost/benefit profile of rituximab therapy for MC.

Life-Threatening Cryoglobulinemic Patients With Hepatitis C: Clinical Description and Outcome of 279 Patients

Cryoglobulinemia is characterized by a wide range of causes, symptoms, and outcomes. Hepatitis C virus (HCV) infection is detected in 30%-100% of patients with cryoglobulins. Although more than half the patients with cryoglobulinemic vasculitis present a relatively benign clinical course, some may present with potentially life-threatening situations. We conducted the current study to analyze the clinical characteristics and outcomes of HCV patients presenting with life-threatening cryoglobulinemic vasculitis. We evaluated 181 admissions from 89 HCV patients diagnosed with cryoglobulinemic vasculitis consecutively admitted to our department between 1995 and 2010. In addition, we performed a systematic analysis of cases reported to date through a MEDLINE search.The following organ involvements were considered to be potentially life-threatening in HCV patients with cryoglobulinemic vasculitis: cryoglobulinemic, biopsy-proven glomerulonephritis presenting with renal failure; gastrointestinal vasculitis; pulmonary hemorrhage; central nervous system (CNS) involvement; and myocardial involvement. A total of 279 patients (30 from our department and 249 from the literature search) fulfilled the inclusion criteria: 205 presented with renal failure, 45 with gastrointestinal vasculitis, 38 with CNS involvement, 18 with pulmonary hemorrhage, and 3 with myocardial involvement; 30 patients presented with more than 1 life-threatening cryoglobulinemic manifestation. There were 146 (52%) women and 133 (48%) men, with a mean age at diagnosis of cryoglobulinemia of 54 years (range, 25-87 yr) and a mean age at life-threatening involvement of 55 years (range, 25-87 yr). In 232 (83%) patients, life-threatening involvement was the first clinical manifestation of cryoglobulinemia. Severe involvement appeared a mean of 1.2 years (range, 1-11 yr) after the diagnosis of cryoglobulinemic vasculitis. Patients were followed for a mean of 14 months (range, 3-120 mo) after the diagnosis of life-threatening cryoglobulinemia. Sixty-three patients (22%) died. The main cause of death was sepsis (42%) in patients with glomerulonephritis, and cryoglobulinemic vasculitis itself in patients with gastrointestinal, pulmonary, and CNS involvement (60%, 57%, and 62%, respectively). In conclusion, HCV-related cryoglobulinemia may result in progressive (renal involvement) or acute (pulmonary hemorrhage, gastrointestinal ischemia, CNS involvement) life-threatening organ damage. The mortality rate of these manifestations ranges between 20% and 80%. Unfortunately, this may be the first cryoglobulinemic involvement in almost two-thirds of cases, highlighting the complex management and very elevated mortality of these cases.

Hepatitis C virus infection, mixed cryoglobulinemia, and kidney disease

Hepatitis C virus (HCV) may instigate mixed cryoglobulinemia; the most significant accompanying kidney lesion is type I membranoproliferative glomerulonephritis, usually occurring in the context of type II mixed cryoglobulinemia. Additionally, recent data support a link between HCV infection and proteinuria in population-based studies, raising the possibility that kidney diseases associated with HCV may be more common than previously thought. A number of strategies have been used to treat HCV-related glomerulonephritis, including antiviral agents, immunosuppressive therapies such as corticosteroids and cytotoxic agents, and plasma exchange. Limited but encouraging data about the utility of antiviral treatment in the setting of HCV-associated glomerulonephritis exist, with one pooled analysis noting a sustained viral response of 42%, albeit with significant heterogeneity. Immunosuppressive therapy may be most useful for cryoglobulinemic kidney disease, with individualized approaches considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis based on the level of proteinuria and kidney failure. Of note, rituximab, a chimeric monoclonal antibody that blocks CD20 receptors on B cells, has been reported to be effective for the treatment of mixed cryoglobulinemia symptoms, including glomerulonephritis.

A randomized controlled trial of rituximab for the treatment of severe cryoglobulinemic vasculitis

OBJECTIVE

To conduct a long-term, prospective, randomized controlled trial evaluating rituximab (RTX) therapy for severe mixed cryoglobulinemia or cryoglobulinemic vasculitis (CV).

METHODS

Fifty-nine patients with CV and related skin ulcers, active glomerulonephritis, or refractory peripheral neuropathy were enrolled. In CV patients who also had hepatitis C virus (HCV) infection, treatment of the HCV infection with antiviral agents had previously failed or was not indicated. Patients were randomized to the non-RTX group (to receive conventional treatment, consisting of 1 of the following 3: glucocorticoids; azathioprine or cyclophosphamide; or plasmapheresis) or the RTX group (to receive 2 infusions of 1 gm each, with a lowering of the glucocorticoid dosage when possible, and with a second course of RTX at relapse). Patients in the non-RTX group who did not respond to treatment could be switched to the RTX group. Study duration was 24 months.

RESULTS

Survival of treatment at 12 months (i.e., the proportion of patients who continued taking their initial therapy), the primary end point, was statistically higher in the RTX group (64.3% versus 3.5% [P < 0.0001]), as well as at 3 months (92.9% versus 13.8% [P < 0.0001]), 6 months (71.4% versus 3.5% [P < 0.0001]), and 24 months (60.7% versus 3.5% [P < 0.0001]). The Birmingham Vasculitis Activity Score decreased only after treatment with RTX (from a mean ± SD of 11.9 ± 5.4 at baseline to 7.1 ± 5.7 at month 2; P < 0.001) up to month 24 (4.4 ± 4.6; P < 0.0001). RTX appeared to be superior therapy for all 3 target organ manifestations, and it was as effective as conventional therapy. The median duration of response to RTX was 18 months. Overall, RTX treatment was well tolerated.

CONCLUSION

RTX monotherapy represents a very good option for severe CV and can be maintained over the long term in most patients.

Hepatitis C virus, cryoglobulinemia, and kidney: novel evidence

Hepatitis C virus infection can lead to chronic active hepatitis, cirrhosis, and liver failure; however, it is also associated with a wide range of extra-hepatic complications. HCV is associated with a large spectrum of histopathological lesions in both native and transplanted kidneys, and it is increasingly recognized as an instigator of B cell lympho-proliferative disorders including mixed cryoglobulinemia. Mixed cyoglobulinemia is a systemic vasculitis primarily mediated by immune complexes; it is characterized by variable organ involvement including skin lesions, chronic hepatitis, glomerulonephritis, peripheral neuropathy, and arthralgias. The most frequent HCV-associated nephropathy is type I membranoproliferative glomerulonephritis, usually in the context of type II mixed cryoglobulinemia. Various approaches have been tried for the treatment of HCV-related glomerulonephritis, including immunosuppressive therapy (corticosteroids and cytotoxic agents), plasma exchange and antiviral agents. Data on the antiviral treatment of HCV-associated glomerulonephritis are not abundant but encouraging results have been provided. Immunosuppressive therapy is particularly recommended for cryoglobulinemic kidney disease. Recent evidence has been accumulated on rituximab therapy for HCV-related cryoglobulinemic glomerulonephritis exists but several questions related to its use remain unclear. Distinct approaches should be considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis according to the level of proteinuria and kidney failure.

Genetic determinants in hepatitis C virus-associated mixed cryoglobulinemia: role of polymorphic variants of BAFF promoter and Fcγ receptors

OBJECTIVE

Mixed cryoglobulinemia (MC) is a hepatitis C virus (HCV)-related immune complex disorder. Only some HCV-infected patients develop MC, which suggests that the genetic background of the host plays a key role. This study was undertaken to evaluate the contribution of host genetic factors in the pathogenesis of HCV-associated MC (HCV-MC) by analyzing allelic variants of low-affinity Fcγ receptor (FcγR) genes and BAFF promoter.

METHODS

FcγR polymorphisms (FCGR2A 131 R/H, FCGR2B 232 I/T, FCGR3A 176 V/F, and FCGR3B NA1/NA2) and BAFF promoter polymorphism -871 C/T were analyzed in 102 patients with HCV-MC and 108 patients with HCV without MC, using polymerase chain reaction-based techniques.

RESULTS

A higher prevalence of -871 T/T homozygosity (31% versus 16%; P = 0.001) and a greater frequency of T alleles of the BAFF promoter (80% versus 57%; P = 0.004) were found in the HCV-MC group than in the HCV group. A significant increase in serum BAFF concentration was significantly associated with the higher frequency of the T allele in HCV-MC (mean ± SD 4.12 ± 1.29 versus 2.09 ± 0.81 ng/ml; P < 0.0005). The distribution of the FcγR genotypes was not significantly different. In the 21 HCV-MC patients treated with rituximab, the response was strictly related to F allele homozygosity (significantly reduced in 5 of 5 patients with the FCGR3A F/F genotype versus 4 of 16 with V/V or V/F; P < 0.0005).

CONCLUSION

These results indicate the importance of host genetic background in the development of HCV-MC, suggesting that mechanisms enhancing Ig production and B cell survival may play a relevant role. Genetic FcγR variants seem to be crucial to the effectiveness of rituximab therapy.

Treatment with rituximab in patients with mixed cryoglobulinemia syndrome: results of multicenter cohort study and review of the literature

OBJECTIVE

Mixed cryoglobulinemia syndrome (MCs) is a systemic vasculitis characterized by multiple organ involvement due to the vascular deposition of immune-complexes, mainly the cryoglobulins. B-lymphocyte expansion represents the underlying pathological alteration frequently triggered by hepatitis C virus (HCV) infection. The treatment of MCs syndrome is generally based on antiviral drugs and/or immunosuppressors, among which rituximab, an anti-CD20 monoclonal antibody, has been usefully employed for both cutaneous and visceral MCs organ involvement. This multicenter study retrospectively evaluated the effects of rituximab in a large series of patients with active MCs. The observed results were compared to those emerging from the updated review of the literature on this topic.

METHODS

The study included 87 patients (male/female 19/68, mean age 62.3±11.4SD years, mean disease duration 9±6.2SD years, HCV infection in 92% of cases) with active cryoglobulinemic vasculitis evaluated before rituximab monotherapy and after 6-month follow-up by means of main clinico-serological parameters. A PubMed search up to May 31, 2011, was done to find published clinical studies, including case reports of MCs treated with rituximab.

RESULTS

A significant clinical improvement was observed in a relevant percentage of cases, regardless the presence/absence of associated HCV infection; namely, complete/partial remission of pre-treatment active manifestations was observed in 74% of skin purpuric lesions, up to 87% of non-healing vasculitic leg ulcers, and 44% of the peripheral neuropathy, mainly paresthesias (patient's visual analogical scale from 62±25 to 37±27; p≤.0001). Moreover, cryoglobulinemic nephropathy, observed in 38 patients, significantly improved in 95% of cases (serum creatinine from 1.8±1.1SD to 1.4±0.8SD mg/dl, p≤.0001; 24-hour proteinuria from 2.2±2.1SD to 0.9±1.7SD g/24h, p≤.0001), with complete remission in the 50%. Among 6 patients with complicating non-Hodgkin's B-cell lymphoma a complete or partial remission was observed in 5/6. A complete remission of abdominal vasculitis was also observed in one patient. These beneficial effects were mirrored by the improvement of cryoglobulinemic serological hallmarks, namely cryocrit and low complement C4, in half cases. The safety of rituximab was confirmed by the small number of side effects recorded during the 6-month follow-up. On the whole, the results of the present study are in keeping with those reported in 39 papers present in world literature, including a total of 279 MCs patients.

CONCLUSIONS

Rituximab may be regarded as useful and safe pathogenetic treatment of cryoglobulinemic vasculitis. The actual role of this drug should be definitely confirmed by randomized controlled trials, as well as its position in the therapeutical strategy, mainly with respect to antiviral treatment in HCV-associated MCs.

Recommendations for the management of mixed cryoglobulinemia syndrome in hepatitis C virus-infected patients

OBJECTIVE

The objective of this review was to define a core set of recommendations for the treatment of HCV-associated mixed cryoglobulinemia syndrome (MCS) by combining current evidence from clinical trials and expert opinion.

METHODS

Expert physicians involved in studying and treating patients with MCS formulated statements after discussing the published data. Their attitudes to treatment approaches (particularly those insufficiently supported by published data) were collected before the consensus conference by means of a questionnaire, and were considered when formulating the statements.

RESULTS

An attempt at viral eradication using pegylated interferon plus ribavirin should be considered the first-line therapeutic option in patients with mild-moderate HCV-related MCS. Prolonged treatment (up to 72 weeks) may be considered in the case of virological non-responders showing clinical and laboratory improvements. Rituximab (RTX) should be considered in patients with severe vasculitis and/or skin ulcers, peripheral neuropathy or glomerulonephritis. High-dose pulsed glucocorticoid (GC) therapy is useful in severe conditions and, when necessary, can be considered in combination with RTX; on the contrary, the majority of conference participants discouraged the chronic use of low-medium GC doses. Apheresis remains the elective treatment for severe, life-threatening hyper-viscosity syndrome; its use should be limited to patients who do not respond to (or who are ineligible for) other treatments, and emergency situations. Cyclophosphamide can be considered in combination with apheresis, but the data supporting its use are scarce. Despite the limited available data, colchicine is used by many of the conference participants, particularly in patients with mild-moderate MCS refractory to other therapies. Careful monitoring of the side effects of each drug, and its effects on HCV replication and liver function tests is essential. A low-antigen-content diet can be considered as supportive treatment in all symptomatic MCS patients. Although there are no data from controlled trials, controlling pain should always be attempted by tailoring the treatment to individual patients on the basis of the guidelines used in other vasculitides.

CONCLUSION

Although there are few controlled randomised trials of MCS treatment, increasing knowledge of its pathogenesis is opening up new frontiers. The recommendations provided may be useful as provisional guidelines for the management of MCS.

Therapeutic targeting of B cells for rheumatic autoimmune diseases

Autoreactive B cells are characterized by their ability to secrete autoantibodies directed against self-peptides. During the last decade, it has become increasingly apparent that B lymphocytes not only produce autoantibodies but also exert important regulatory roles independent of their function as antibody-producing cells. This is especially relevant in the context of autoimmunity, because autoreactive B cells have been shown to possess the ability to activate pathogenic T cells, to produce pro-inflammatory cytokines, and to promote the formation of tertiary lymphoid tissue in target organs. The production of monoclonal antibodies against B-cell-surface molecules has facilitated the characterization of several distinct B lymphocyte subsets. These cell-surface molecules have not only served as useful cell differentiation markers but have also helped to unravel the important biological functions of these cells. Some of these molecules, all of which are expressed on the cell surface, have proven to be effective therapeutic targets. In both animal models and in clinical assays, the efficient elimination of B lymphocytes has been shown to be useful in the treatment of rheumatoid arthritis and other autoimmune diseases. The treatment of most rheumatic autoimmune diseases relies mainly on the use of cytotoxic immunosuppressants and corticosteroids. Although this has resulted in improved disease survival, patients may nonetheless suffer severe adverse events and, in some cases, their relapse rate remains high. The increasing need for safer and more effective drugs along with burgeoning new insights into the pathogenesis of these disorders has fueled interest in biological agents; clinical trials involving the B-cell depletion agent rituximab have been especially promising. This article reviews the current knowledge of B-cell biology and pathogenesis as well as the modern therapeutic approaches for rheumatic autoimmune diseases focusing in particular on the targeting of B-cell-specific surface molecules and on the blocking of B-cell activation and survival.

Rituximab in cryoglobulinaemic vasculitis, evidence for its effectivity: a case report and review of literature

Cryoglobulinaemia associated with systemic vasculitis mediated by immune complexes is a rare combination. These immune complexes are composed of immunoglobulins and precipitate when exposed to cold temperature. Cryoglobulinaemic vasculitis, treated or untreated, may lead to substantial morbidity and even mortality. Novel targeted therapies may well provide new therapeutic options following or perhaps even prior to the classical cytotoxic therapies. Systemic B cell depletion with rituximab, a chimeric monoclonal antibody against CD20 antigen, is commonly applied in patients with non-Hodgkin's lymphoma or in refractory rheumatoid factor-positive rheumatoid arthritis. Since B cell clones are the source of cryoglobulins, therapeutic effectiveness of rituximab in cryoglobulinaemic vasculitis may be expected. We describe a 72-year-old woman with mixed cryoglobulinaemia type 2, who has successfully been treated with rituximab infusions after failing on prednisone and azathioprine. We reviewed the literature and found 142 cases of cryoglobulinaemic vasculitis, 138 mixed (type 2 or 3) and four, type 1. Rituximab was applied mostly after failure on other treatments. Significant reduction in levels of rheumatoid factor, cryoglobulins and IgM were reported after rituximab therapy. Of the total 142, cases 119 could be evaluated for the response on rituximab therapy, the other 23 cases only regarding side effects. Of the 119 evaluated patients, 71 (60%) had complete response; 28 (23%), partial response and 20 patients (17%), no response. Data were not blinded or placebo-controlled. Side effects were seen in 27 of the 142 patients. Occurrence of the side effects was associated with high baseline levels of cryoglobulins, with a high dose of rituximab infusion of 1,000 mg and with a high level of complement activation. Death was reported four times and was related with the disease.

CD20-depleting therapy in autoimmune diseases: from basic research to the clinic

The B lymphocyte-associated antigen CD20 is becoming an important immunotherapy target for autoimmune diseases, although its biological function has not been defined. Besides rheumatoid arthritis, growing experience with B cell-depleting therapy indicates that it may be effective in Sjögren's syndrome, dermatomyositis-polymyositis, systemic lupus erythematosus and some types of vasculitides. However, controlled clinical trials are still lacking for some of these indications. Infection has not been seen as a major limitation to this therapy, but reports of progressive multifocal leukoencephalopathy in an extremely small number of patients are of concern. Here, we review the therapeutic actions of anti-CD20 antibodies, and the recent and ongoing clinical trials with CD20-depleting therapy in autoimmune diseases.

Rituximab may form a complex with IgMkappa mixed cryoglobulin and induce severe systemic reactions in patients with hepatitis C virus-induced vasculitis

OBJECTIVE

To report on 6 cases of hepatitis C virus (HCV)-induced mixed cryoglobulinemia (MC) vasculitis in patients who developed severe systemic reactions after rituximab infusion, and to report the results of the in vitro analysis of the underlying immunologic mechanisms.

METHODS

Twenty-two HCV-infected patients with MC vasculitis received rituximab infusions (a low-dose protocol cycle with 375 mg/m2/week for 4 consecutive weeks in 18 patients and a high-dose protocol cycle with 1,000 mg on days 1 and 15 in 4 patients). Systemic drug reactions following rituximab infusion were recorded and analyzed clinically and immunochemically.

RESULTS

Six of 22 patients (27.3%) experienced systemic drug reactions after rituximab infusion. Four patients developed a severe flare of MC vasculitis 1 or 2 days after rituximab infusion. Two patients developed serum sickness syndrome 7 and 9 days after the first 1,000 mg rituximab infusion. Compared with patients without drug reactions, those with drug reactions had higher mixed cryoglobulin levels (mean+/-SD 1.4+/-0.82 gm/liter versus 0.71+/-0.77 gm/liter; P=0.0475) and lower C4 levels (mean+/-SD 0.02+/-0.006 gm/liter versus 0.07+/-0.07 gm/liter; P=0.02), and more of them received 1,000 mg high-dose rituximab protocol (50% versus 6.25%; P=0.046). In vitro immunochemical assays showed that rituximab formed a complex with the cryoprecipitating IgMkappa that had rheumatoid factor (RF) activity. Moreover, the in vitro addition of rituximab to serum containing an RF-positive IgMkappa type II mixed cryoglobulin was associated with visibly accelerated cryoprecipitation.

CONCLUSION

In HCV-associated MC vasculitis, rituximab may form a complex with RF-positive IgMkappa, leading to accelerated cryoprecipitation and to severe systemic reactions. Rituximab should be administered with caution in MC vasculitis, with use of the 375 mg protocol and plasma exchanges prior to rituximab infusion in patients with high baseline levels of mixed cryoglobulin.

Causes and Predictive Factors of Mortality in a Cohort of Patients with Hepatitis C Virus-related Cryoglobulinemic Vasculitis Treated with Antiviral Therapy

Objective.

Hepatitis C virus (HCV)-associated mixed cryoglobulinemia (MC) vasculitis is an autoimmune disorder with significant morbidity and mortality. Renal involvement was associated with an increased mortality, and was the most common cause of death; these data were obtained before effective antiviral treatment was available. We studied causes of death and predictive factors in patients with HCV-associated MC vasculitis treated with antivirals.

Methods.

Case histories of 85 patients with HCV-associated MC vasculitis treated in a single center between 1990 and 2006 were retrospectively reviewed. Prognostic factors affecting mortality were studied by comparing 23 patients who died with 62 survivors, using the Cox model regression analysis.

Results.

The most common cause of death was infection, accounting for 34.7%, followed by endstage liver disease in 30.4% (including 4 patients with hepatocellular carcinoma), and cardiovascular disease in 17.4% of patients. Endstage renal disease accounted for only 8.7% of deaths, as did central nervous system vasculitis and nonhepatic malignancy. Increased mortality was strongly associated with immunosuppressive treatment [hazard ratio (HR) 6.51, 95% CI 2.75–15.37], cutaneous ulcers (HR 5.37, 95% CI 1.79–16.14), and renal insufficiency (HR 3.25, 95% CI 1.37–7.72). A 2 log10 decrease in HCV viral load at month 3 after starting antiviral treatment was associated with decreased mortality (HR 0.39, 95% CI 0.16–0.95).

Conclusion.

While renal involvement is still associated with poorer prognosis, infectious processes are now the most common cause of death in HCV cryoglobulinemia vasculitis. Immunosuppressive treatment is associated with an increased risk of death, independently from disease severity. Response to antiviral treatment is associated with significantly reduced mortality risk.

Novel B cell therapeutic targets in transplantation and immune-mediated glomerular diseases

B cells and antibodies play an important role in the alloresponse to renal grafts as well as in immune-mediated glomerular diseases. In transplantation, greater recognition and improved diagnosis of antibody-mediated rejection have been a catalyst to the introduction of newer drugs and regimens that target B cells, plasma cells, and donor-specific antibodies to improve the outcome associated with antibody-mediated rejection. In immune-mediated renal disease, novel and more selective B cell therapies are gradually modifying the traditional therapeutic approach that consists of steroids and other immunosuppressants. A new era of selective and more effective immunosuppression agents that target the humoral response is finally emerging in transplantation and renal diseases.

Off-label use of rituximab in a tertiary Queensland hospital

BACKGROUND

Rituximab is a monoclonal antibody directed against CD20, a pan B lymphocyte marker. It is approved in Australia for treatment of CD20-positive B cell non-Hodgkin lymphoma and rheumatoid arthritis. There is increasing off-label use of rituximab in conditions where B cells and autoantibodies play a role in the pathophysiology. Rituximab is not only expensive, but its safety in unregistered indications is uncertain.

METHODS

We performed a retrospective review of the off-label use of rituximab approved by the High Cost Drug Subcommittee at the Princess Alexandra Hospital between 2005 and 2008. Cases of post transplant lymphoproliferative disorder were excluded.

RESULTS

A total of 28 patients received rituximab for a variety of off-label indications. There were no reported cases of serious infusion reactions or other notable adverse events. The most favourable outcomes were seen in myasthenia gravis, shrinking lung syndrome, thrombotic thrombocytopenic purpura, prevention and treatment of renal transplant rejection and lupus nephritis. No benefit was observed in cases of focal segmental glomerulosclerosis (primary or post-transplant recurrence) and post-transplant recurrence of haemolytic uremic syndrome. There was limited benefit in cryoglobulinaemic vasculitis. The cost of off-label use was in excess of $210,000.

CONCLUSION

In the absence of formal clinical trials, decisions regarding off-label use of rituximab are difficult. Our cases contribute to the published literature and should help provide clinicians with greater insights into which conditions are likely to respond. As can be seen in our series, rituximab benefits people with certain conditions; longevity and cost-effectiveness are currently unknown.

B-cell-directed therapy for inflammatory skin diseases

The basic understanding of inflammatory dermatoses and autoimmune-mediated skin disorders has greatly advanced and broadened our understanding of underlying immune mechanisms that shape the complex network of chronic inflammation and autoimmunity. The new treatment options for psoriasis exemplify how new insights into (auto)immune responses, especially the role and function of various immune cells and proinflammatory cytokines, may lead to new therapeutic strategies. The concept of targeting B cells in autoimmune-mediated disorders is closely related to the discovery of autoantibodies and their cellular origin. However, the appreciation of B cells in autoimmunity has significantly changed and is not limited to their role as progenitors of autoantibody secreting plasma cells. Recent investigations of various inflammatory skin diseases, that is, autoimmune blistering disorders, collagen vascular diseases, and atopic dermatitis, actually support the concept that B cells might be as important as T cells in the etiopathogenesis of these disorders. The striking clinical improvement seen in patients with rheumatoid arthritis following B-cell depletion with the anti-CD20 mAb rituximab has tremendously catalyzed the interest in B-cell-targeted therapies in different autoimmune diseases. Future translational and clinical investigations are mandatory to precisely define the role and the contribution of impaired B-cell function in (auto)immune-mediated skin diseases.

Safety of biologic therapy in rheumatoid arthritis and other autoimmune diseases: focus on rituximab

OBJECTIVES

To review the safety of biologic agents used to treat rheumatoid arthritis (RA) and other autoimmune diseases, with a focus on rituximab.

METHODS

Information was gathered from a search of the PubMed database and from major congress abstract listings through June 2007.

RESULTS

Rituximab is approved for treating RA in patients with an inadequate response to TNF inhibitors and is under study in other indications for RA and other autoimmune disorders. The current safety profile of rituximab in RA is known from Phase II and III studies conducted preapproval, treating approximately 750 patients, as well as from long-term extension studies with repeated therapy. Clinical trials have established that the most common adverse events are infusion-associated reactions, seen in 29 to 40% of patients, most of which are mild to moderate and occur following the first rituximab infusion, with incidence and severity decreasing with subsequent infusions. Rates of infections and serious infections to date are within the range expected for RA patients treated with other biologic agents, but the longer term effects of B-cell depletion and the effects of repeated treatment on the risk of infections are uncertain. Information is limited for rituximab safety in other autoimmune disorders but current data do not suggest that there is a significant difference in adverse events from that previously reported.

CONCLUSIONS

Rituximab is an important addition to the rheumatologist's armamentarium for the treatment of difficult RA and ongoing trials will determine its utility in other indications for RA and other autoimmune conditions. The true safety profile of rituximab will emerge as larger numbers of patients are treated in routine clinical practice.