Sustained improvement in rheumatoid arthritis following a protocol designed to deplete B lymphocytes

B cell phenotypes in patients with rheumatoid arthritis relapsing after rituximab: expression of B cell-activating factor-binding receptors on B cell subsets

Serum levels of B cell-activating factor (BAFF) rise following rituximab (RTX) therapy in patients with rheumatoid arthritis (RA). Initiation of naive B cell return to the periphery and autoreactive B cell expansion leading to relapse after RTX may therefore be linked to interactions between BAFF and BAFF-binding receptors (BBR). Relationships between serum BAFF and BBR expression [(BAFFR, calcium signal modulating cyclophilic ligand interactor (TACI) and B cell maturation antigen (BCMA)] were determined on B cell subsets, defined using immunoglobulin (Ig)D/CD38. Twenty pre-RTX and 18 RA patients relapsing after B cell depletion were included. Results were analysed with respect to timing of relapse up to 7 months after peripheral B cell return (≥ 5 B cells/μl) and to serum BAFF levels. After B cell return, B cell populations from relapsing patients had significantly lower BAFFR⁺ expression compared to HC and pre-RTX patients. The percentage of BAFFR⁺ B cells increased with time after B cell return and was correlated inversely with serum BAFF levels. BAFFR expression remained reduced. The percentage of TACI⁺ memory B cells were lower in RA patients after RTX compared with healthy controls (HC). BCMA expression (% and expression) did not differ between patients and HC. Relapse following B cell return appeared largely independent of the percentage of BAFFR⁺ or percentage of BCMA⁺ B cells or serum BAFF levels. The lower percentage of TACI⁺ memory B cells may reduce inhibitory signalling for B cell differentiation. In patients relapsing at longer periods after B cell return, recovery of the B cell pool was more complete, suggesting that selection or expansion of autoreactive B cells may be needed to precipitate relapse.

Ultra-low dose of rituximab in rheumatoid arthritis: study protocol for a randomised controlled trial

Background

A standard low-dosing schedule of rituximab (RTX; 2 × 500 mg or 1 × 1000 mg) is as effective for active rheumatoid arthritis (RA) as the registered dose (2 × 1000 mg). Moreover, several small uncontrolled studies suggest that even lower-dosed treatment with RTX also leads to good treatment response in patients with RA. Retreatment with such an ‘ultra-low’ dose RTX in patients who responded well to RTX induction treatment is of special interest, as long-term use of lower RTX doses may lead to shorter infusion duration, lower risk of adverse events and lower costs. However, the effect of ultra-low dose of RTX has not been investigated using a controlled trial of proper design and dimensions.

Methods/Design

REDO is an investigator driven six-month pragmatic, double-blind, randomised controlled non-inferiority trial on the effects of ultra-low-dose RTX (1 × 500 or 1 × 200 mg) compared to standard low dose (1 × 1000 mg) in RA patients who are being retreated with RTX. A total of 140 RA patients, having reached low disease activity (DAS28CRP < 2.9) after the previous RTX infusion and DAS28CRP < 3.5 at moment of retreatment, are randomised in a ratio of 1:2:2 to 1 × 1000 mg, 1 × 500 mg or 1 × 200 mg. The primary objective is testing non-inferiority of the ultra-low-dose vs. standard low-dose RTX, by comparing mean change in DAS28CRP from baseline to six months to the non-inferiority margin of 0.6. Secondary outcomes over the same period are: function; quality of life; safety; costs; and pharmacokinetics and dynamics as process measures.

Discussion

This study protocol shares characteristics of both early dose finding trials as well as late pragmatic clinical studies. Several choices in the design of this trial are described and possible consequences for RA treatment and expected biosimilar introduction are discussed.

Trial registration

Dutch Trial Register, NTR6117. Registered on 15 November 2016 (CMO NL57520.091.16, 8 November 2016)

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2134-x) contains supplementary material, which is available to authorized users.

Infectious complications of rituximab therapy in renal disease

Rituximab, an anti-CD20 monoclonal antibody, was originally used to treat B-cell malignancies. Its use has significantly increased in recent years, as it is now also used to treat a variety of autoimmune diseases including rheumatoid arthritis and ANCA-associated vasculitis (AAV). Initial studies suggested that the adverse effects of rituximab were minimal. Though the risk of malignancy with rituximab-based immunosuppressive regimens appears similar to that of the general population, there are now concerns regarding the risk of infectious complications. Rituximab has been associated with serious infections, including Pneumocystis jiroveci pneumonia (PJP) and the reactivation of hepatitis B virus (HBV) and tuberculosis (TB). The risk of infection appears to be the result of a variety of mechanisms, including prolonged B-cell depletion, B-cell–T-cell crosstalk, panhypogammaglobulinaemia, late-onset neutropenia and blunting of the immune response after vaccination. Importantly, the risk of infectious complications is also related to individual patient characteristics and the indication for rituximab. Individualization of treatment is, therefore, crucial. Particular attention should be given to strategies to minimize the risk of infectious complications, including vaccinating against bacterial and viral pathogens, monitoring white cell count and immunoglobulin levels, prophylaxis against PJP and screening for HBV and TB.

A multi-parameter response prediction model for rituximab in rheumatoid arthritis

OBJECTIVES

To validate the IFN response gene (IRG) set for the prediction of non-response to rituximab in rheumatoid arthritis (RA) and assess the predictive performance upon combination of this gene set with clinical parameters.

METHODS

In two independent cohorts of 93 (cohort I) and 133 (cohort II) rituximab-starting RA patients, baseline peripheral blood expression of eight IRGs was determined, and averaged into an IFN score. Predictive performance of IFN score and clinical parameters was assessed by logistic regression. A multivariate prediction model was developed using a forward stepwise selection procedure. Patients with a decrease in disease activity score (ΔDAS28)≥1.8 after 6 months of therapy were considered responders.

RESULTS

The mean IFN score was higher in non-responders compared to responders in both cohorts, but this difference was most pronounced in patients who did not use prednisone, as described before. Univariate analysis in cohort I showed that baseline DAS28, IFN score, DMARD use and negativity for IgM-RF and/or ACPA were associated with rituximab non-response. The multivariate model consisted of DAS28, IFN score and DMARD use, which showed an area under the curve (AUC) of 0.82. In cohort II, this model revealed a comparable AUC in PREDN-negative patients (0.78), but AUC in PREDN-positive patients was significantly lower (0.63), which seemed due to effect modification of the IFN score by prednisone.

CONCLUSIONS

Combination of predictive parameters provided a promising model for the prediction of non-response to rituximab, with possibilities for optimization via definition of the exact interfering effect of prednisone on IFN score.

TRIAL REGISTRATION (COHORT II, SMART TRIAL)

NCT01126541, registered 18 May 2010.

mRNA profiling identifies low levels of phosphatases dual‐specific phosphatase‐7 (DUSP7) and cell division cycle‐25B (CDC25B) in patients with early arthritis

Phosphotyrosine phosphatases (PTPs) control phosphorylation levels and, consequently, regulate the output of intracellular signalling networks in health and disease. Despite the high number of PTPs expressed in CD4 T cells and their involvement in autoimmunity, information about the expression profile of PTPs in these cells has not been obtained in patients diagnosed with autoimmune diseases. Here, we compare the expression profile of PTPs in CD4 T cells of healthy volunteers and patients submitted to an early arthritis clinic, due to suspicion of rheumatoid arthritis, an autoimmune disease mediated by CD4 T cells. We found lower transcript levels of the mitogen-activated protein kinase (MAPK) phosphatase dual-specific phosphatase-7 (DUSP7) and the cell division cycle-25B (CDC25B) in T cells of patients. While the low expression level of DUSP7 was restricted to patients with positive rheumatoid factor and anti-citrullinated protein antibodies, the altered expression of CDC25B correlated with the activity of the disease. Low levels of CDC25B might contribute to the progression of the autoimmune arthritis and/or might be consequence of the inflammatory environment in the active disease. The possible role of DUSP7 and CDC25B as biomarkers of the disease in clinical protocols is discussed.

B cells expressing the IgA receptor FcRL4 participate in the autoimmune response in patients with rheumatoid arthritis

The clinical efficacy of B cell targeting therapies highlights the pathogenic potential of B cells in inflammatory diseases. Expression of Fc Receptor like 4 (FcRL4) identifies a memory B cell subset, which is enriched in the joints of patients with rheumatoid arthritis (RA) and in mucosa-associated lymphoid tissue. The high level of RANKL production by this B cell subset indicates a unique pathogenic role. In addition, recent work has identified a role for FcRL4 as an IgA receptor, suggesting a potential function in mucosal immunity. Here, the contribution of FcRL4+ B cells to the specific autoimmune response in the joints of patients with RA was investigated.

Single FcRL4+ and FcRL4- B cells were sorted from synovial fluid and tissue from RA patients and their immunoglobulin genes characterized. Levels of hypermutation in the variable regions in both populations were largely consistent with memory B cells selected by an antigen- and T cell-dependent process. Recombinant antibodies were generated based on the IgH and IgL variable region sequences and investigated for antigen specificity. A significantly larger proportion of the recombinant antibodies generated from individual synovial FcRL4+ B cells showed reactivity towards citrullinated autoantigens. Furthermore, both in analyses based on heavy chain sequences and flow cytometric detection, FcRL4+ B cells have significantly increased usage of the IgA isotype. Their low level of expression of immunoglobulin and plasma cell differentiation genes does not suggest current antibody secretion. We conclude that these activated B cells are a component of the local autoimmune response, and through their RANKL expression, can contribute to joint destruction. Furthermore, their expression of FcRL4 and their enrichment in the IgA isotype points towards a potential role for these cells in the link between mucosal and joint inflammation.

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Memory B cells expressing the IgA receptor FcRL4 are found in the joints of patients with RA.

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B cell receptors expressed on synovial FcRL4+ B cells more frequently belong to the IgA class.

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Among recombinant antibodies cloned from FcRL4+ B cells there is more reactivity with citrullinated proteins.

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The gene transcription profile of FcRL4+ B cells shows a low level of differentiation to plasma cells.

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These cells may be involved in the link between mucosal and joint autoimmunity.

Inflammatory Cell Migration in Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that primarily affects the joints. Self-reactive B and T lymphocytes cooperate to promote antibody responses against self proteins and are major drivers of disease. T lymphocytes also promote RA independently of B lymphocytes mainly through the production of key inflammatory cytokines, such as IL-17, that promote pathology. While the innate signals that initiate self-reactive adaptive immune responses are poorly understood, the disease is predominantly caused by inflammatory cellular infiltration and accumulation in articular tissues, and by bone erosions driven by bone-resorbing osteoclasts. Osteoclasts are giant multinucleated cells formed by the fusion of multiple myeloid cells that require short-range signals, such as the cytokines MCSF and RANKL, for undergoing differentiation. The recruitment and positioning of osteoclast precursors to sites of osteoclast differentiation by chemoattractants is an important point of control for osteoclastogenesis and bone resorption. Recently, the GPCR EBI2 and its oxysterol ligand 7a, 25 dihydroxycholesterol, were identified as important regulators of osteoclast precursor positioning in proximity to bone surfaces and of osteoclast differentiation under homeostasis. In chronic inflammatory diseases like RA, osteoclast differentiation is also driven by inflammatory cytokines such as TNFa and IL-1, and can occur independently of RANKL. Finally, there is growing evidence that the chemotactic signals guiding osteoclast precursors to inflamed articular sites contribute to disease and are of great interest. Furthering our understanding of the complex osteoimmune cell interactions should provide new avenues of therapeutic intervention for RA.

Review on the Influence of Protocol Design on Clinical Outcomes in Rheumatoid Arthritis Treated with Rituximab

OBJECTIVE

To critically analyze the influence of protocol design on clinical outcome in patients with rheumatoid arthritis (RA) treated with rituximab.

DATA SOURCES

A PubMed and EMBASE search (January 2000-January 2012) using the key words rheumatoid arthritis and rituximab was performed.

STUDY SELECTION AND DATA EXTRACTION

A search of English-language studies from the data sources was conducted for randomized, double-blind, placebo-controlled studies with 100 patients or more assessing the efficacy and safety of rituximab in the treatment of RA. From these studies, 2 authors independently extracted, compiled, and aggregated the data.

DATA SYNTHESIS

Eight studies met the inclusion criteria. In these studies, some patients had not been treated with tumor necrosis factor-alfa (TNF-α) inhibitors, while most did not respond to it. The variables compared included dose (500 vs 1000 mg), duration of study (24 vs 48 weeks), and number of cycles (1 vs 2). They were statistically analyzed using the χ2 test. There was a statistically significant difference in the response to rituximab compared to the control (methotrexate) (p < 0.001). In patients who were studied for only 24 weeks, given 500 or 1000 mg for 1 or 2 cycles, a 90% or greater response rate was reported in those who achieved an ACR 20, but no statistically significant differences were observed (p = 0.75). In patients studied for 48 weeks who received 2 cycles of either 500 mg or 1000 mg of rituximab and achieved an ACR 20, a statistically significant difference (p < 0.001) was observed in those who received a dose of 1000 mg for 2 cycles (42.77% vs 67.49%).

CONCLUSIONS

In patients who are nonresponsive to disease-modifying antirheumatic drugs and TNF-α inhibitors, rituximab may be a promising and well-tolerated biologic agent. The capacity of rituximab to produce long-term, sustained remissions could not be evaluated because the duration of the studies was limited to 24 weeks or 48 weeks. Studies with longer periods of observation are warranted.

Improving B-cell depletion in systemic lupus erythematosus and rheumatoid arthritis

INTRODUCTION

Rituximab-based B-cell depletion (BCD) therapy is effective in refractory rheumatoid arthritis (RA) and although used to treat patients with refractory systemic lupus erythematosus (SLE) in routine clinical practice, rituximab failed to meet the primary endpoints in two large randomised controlled trials (RCTs) of non-renal (EXPLORER) and renal (LUNAR) SLE. Areas covered: We review how BCD could be improved to achieve better clinical responses in RA and SLE. Insights into the variability in clinical response to BCD in RA and SLE may help develop new therapeutic strategies. To this end, a literature search was performed using the following terms: rheumatoid arthritis, systemic erythematosus lupus, rituximab and B-cell depletion. Expert commentary: Poor trial design may have, at least partly, contributed to the apparent lack of response to BCD in the two RCTs of patients with SLE. Enhanced B-cell depletion and/or sequential therapy with belimumab may improve clinical response at least in some patients with SLE.

Developing connections amongst B lymphocytes and deregulated pathways in autoimmunity

Immunologists have long investigated B lymphocytes as solely antibody producing cells. With further studies, it became clear that B cells are able to exert a variety of functions within the immune system, and beyond. As a result, B cells are considered promising targets for immunotherapy in a variety of disorders. Recently, experts in B cell biology and autoimmunity convened to discuss important stepping stones to decipher the complexity of B lymphocyte-mediated pathways in autoimmune diseases.

Safety and Efficacy of SBI-087, a Subcutaneous Agent for B Cell Depletion, in Patients with Active Rheumatoid Arthritis: Results from a Phase II Randomized, Double-blind, Placebo-controlled Study

OBJECTIVE

To evaluate subcutaneous SBI-087 to treat rheumatoid arthritis (RA).

METHODS

A total of 210 adult patients with active RA were randomized to receive either 200 mg SBI-087 or placebo (Pbo), according to one of these patterns: SBI/Pbo/Pbo (SBI on Day 1), SBI/SBI/Pbo (SBI days 1 and 15), SBI/Pbo/SBI (SBI days 1 and 84), SBI/SBI/SBI (SBI days 1, 15, and 84), or Pbo/Pbo/Pbo (Pbo all 3 days). All patients were seropositive and taking background methotrexate. The primary endpoint was proportion of patients achieving 20% improvement from baseline at Week 16 by American College of Rheumatology criteria (ACR20). Other outcomes included 28-joint Disease Activity Score (DAS28)-C-reactive protein (CRP), physician's and patient's global assessments of disease activity (PGA and PtGA, respectively) and Health Assessment Questionnaire-Disability Index (HAQ-DI). Peripheral CD19+ B cells were measured by high-sensitivity flow cytometer. Statistical significance was set at 2-sided α 0.10 level.

RESULTS

The SBI/SBI/SBI group demonstrated significant improvement in ACR20 and DAS28-CRP from Week 8 onward, sustained improvement in CRP levels from Week 12 onward, and significant improvements in PGA and PtGA in weeks 16 through 24, and in HAQ-DI at Week 24. The SBI/Pbo/Pbo and SBI/SBI/Pbo groups did not meet the primary endpoint but demonstrated improvements in several secondary endpoints. All treatment groups exhibited depletion of peripheral CD19+ B cells throughout the study. Overall, 61.5% of patients receiving SBI-087 and 55.0% of patients receiving Pbo reported adverse events.

CONCLUSION

SBI-087 effectively depleted peripheral CD20 B cells and was well tolerated. Improvements were consistently observed in the SBI/SBI/SBI group for the majority of efficacy and quality-of-life outcomes.

Cytokine-producing B cells: a translational view on their roles in human and mouse autoimmune diseases

B-cell depletion therapy has beneficial effects in autoimmune diseases. This is only partly explained by an elimination of autoantibodies. How does B-cell depletion improve disease? Here, we review preclinical studies showing that B cells can propagate autoimmune disorders through cytokine production. We also highlight clinical observations indicating the relevance of these B-cell functions in human autoimmunity. Abnormalities in B-cell cytokine production have been observed in rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, and systemic lupus erythematosus. In the first two diseases, B-cell depletion erases these abnormalities, and improves disease progression, suggesting a causative role for defective B-cell cytokine expression in disease pathogenesis. However, in the last two disorders, the pathogenic role of B cells and the effect of B-cell depletion on cytokine-producing B cells remain to be clarified. A better characterization of cytokine-expressing human B-cell subsets, and their modulation by B cell-targeted therapies might help understanding both the successes and failures of current B cell-targeted approaches. This may even lead to the development of novel strategies to deplete or amplify selectively pathogenic or protective subsets, respectively, which might be more effective than global depletion of the B-cell compartment.

Anti-B cell therapy (Rituximab) in the treatment of autoimmune diseases

The use of B cell depletion as a mode of treatment for non-Hodgkin’s lymphoma was first utilized in 1997 when Rituximab, a chimeric human-mouse monoclonal antibody which has a high affinity to the CD20 antigen expressed on B cells, became available. Over 500 000 lymphoma patients have been treated worldwide with this drug and it has a good safety record. The notion that B cells might be critical to the development of rheumatoid arthritis led to the extension of the use of B cell depletion to this condition and a recent double blind controlled trial has shown very encouraging results. In addition, B cell depletion either using Rituximab alone, or in combination with cyclophosphamide and corticosteroids has also been reported to have been of great benefit in some patients with severe systemic lupus erythematosus albeit in open label studies. This review considers the mechanism of action of the drug, the clinical trials that have been reported, and tries to place its current use in patients with autoimmune rheumatic disease in context.

Remission of refractory lupus nephritis with a protocol including rituximab

Immunosuppression with corticosteroids and cyclophosphamide is the standard of care for lupus nephritis. We report a 19-year old woman with lupus nephritis and nephrotic syndrome who had not achieved complete remission after treatment with 15.7g cyclophosphamideand 13.7g prednisone.We planned a consolidation phase with: 1) cyclophosphamide 20mg/kg i.v. every 28 days for three cycles; 2) anti-CD20 chimeric monoclonal antibody (rituximab) 375mg/m2i.v. weekly for four weeks; and 3) slow tapering of prednisone p.o., q.o.d., after a reinduction dose during rituximab administration. At the end of this phase the patient achieved complete remission. An indefinite maintenance treatment with methotrexate, cyclosporin and low-dose prednisone was then started. Twenty-four months later the patient remains in remission. In the immunosuppressive treatment of lupusnephritisthe insertionof a consolidationphasewith rituximab combinedwith cyclophosphamide achieves a therapeutically important and lasting deletion of the lymphocyte clone responsible for autoimmunity.

Safety of Repeated Open-Label Treatment Courses of Intravenous Ofatumumab, a Human Anti-CD20 Monoclonal Antibody, in Rheumatoid Arthritis: Results from Three Clinical Trials

Objectives

To investigate the safety of ofatumumab retreatment in rheumatoid arthritis.

Methods

Patients with active rheumatoid arthritis participating in two phase III trials (OFA110635 and OFA110634) and a phase II extension trial (OFA111752) received individualised open-label ofatumumab retreatment (700 mg X 2 intravenous infusions two weeks apart) ≥24 weeks following the first course and ≥16 weeks following further courses. Retreatment required evidence of clinical response followed by disease relapse. These studies were prematurely terminated by the sponsor to refocus development on subcutaneous delivery. Due to differences in study designs and populations, data are summarised separately for each study.

Results

483 patients (243, 148 and 92 in OFA110635, OFA110634 and OFA111752 respectively) received up to 7 treatment courses of intravenous ofatumumab; cumulative duration of exposure was 463, 182 and 175 patient-years, respectively. Mean time between courses was 17–47 weeks. Ofatumumab induced a profound depletion of peripheral B-lymphocytes. Retreated patients derived benefit based on improvement in DAS28. Adverse events were reported for 93% (226/243), 91% (134/148) and 76% (70/92), serious adverse events for 18% (44/243), 20% (30/148) and 12% (11/92) and serious infections for 3% (8/243), 5% (7/148) and 1% (1/92) of patients in OFA110635, OFA110634 and OFA111752, respectively. The most common adverse events were infusion-related reactions during the first infusion of the first course (48–79%); serious infusion-related reactions were rare (<1% [1/243], 5% [8/148], and 1% [1/92] of patients). Two deaths occurred (fulminant hepatitis B virus infection and interstitial lung disease).

Conclusions

Ofatumumab was generally well tolerated with no evidence of increased safety risks with multiple retreatments. Serious infections were uncommon and did not increase over time.

Trial Registration

ClinicalTrials.gov 110635

ClinicalTrials.gov 110634

ClinicalTrials.gov 111752

Regulatory T Cell Dysfunction Acquiesces to BTLA+ Regulatory B Cells Subsequent to Oral Intervention in Experimental Autoimmune Encephalomyelitis

Regulatory T cells (Tregs) induced during autoimmunity often become quiescent and unable to resolve disease, suggesting inadequate activation. Resolution of established experimental autoimmune encephalomyelitis (EAE) can be achieved with myelin oligodendrocyte glycoprotein (MOG) fused to reovirus protein σ1 (MOG-pσ1), which activates Tregs, restoring protection, but requiring other regulatory cells to revitalize them. B cells have a dichotomous role in both the pathogenesis and recovery from EAE. Although inflammatory B cells contribute to EAE's pathogenesis, treatment of EAE mice with MOG-pσ1, but not OVA-pσ1, resulted in an influx of IL-10-producing B220(+)CD5(+) B regulatory cells (Bregs) enabling Tregs to recover their inhibitory activity, and in turn, leading to the rapid amelioration of EAE. These findings implicate direct interactions between Bregs and Tregs to facilitate this recovery. Adoptive transfer of B220(+)CD5(-) B cells from MOG-pσ1-treated EAE or Bregs from PBS-treated EAE mice did not resolve disease, whereas the adoptive transfer of MOG-pσ1-induced B220(+)CD5(+) Bregs greatly ameliorated EAE. MOG-pσ1-, but not OVA-pσ1-induced IL-10-producing Bregs, expressed elevated levels of B and T lymphocyte attenuator (BTLA) relative to CD5(-) B cells, as opposed to Tregs or effector T (Teff) cells, whose BTLA expression was not affected. These induced Bregs restored EAE Treg function in a BTLA-dependent manner. BTLA(-/-) mice showed more pronounced EAE with fewer Tregs, but upon adoptive transfer of MOG-pσ1-induced BTLA(+) Bregs, BTLA(-/-) mice were protected against EAE. Hence, this evidence shows the importance of BTLA in activating Tregs to facilitate recovery from EAE.

The Tumor Microenvironment Regulates CD19 and CD20 Immunotherapy for Lymphoma

B cells have diverse functions during immune responses, including antibody production, antigen presentation, and cytokine secretion. Multiple lymphomas and leukemias derive from malignant B cells, so therapies that deplete B cells are clinically important, particularly antibodies targeting the B cell-specific surface molecules CD19 and CD20. Macrophages are the principal mediators of CD19 and CD20 monoclonal antibody-dependent B-cell and lymphoma depletion in mice through Fcγ receptor-dependent phagocytosis. Thereby, the extent of CD19 or CD20 antibody-induced B cell and tumor depletion in vivo is influenced by molecular changes within tumors and genetic variations between individuals. In addition to Fcγ receptor polymorphisms, lymphoma- and regulatory B cell-derived cytokine production and macrophage localization and function within tumor microenvironments influence tumor clearance. Given the dynamic interactions of these factors, the identification of effector cell and tumor microenvironment genetic alterations will identify molecular targets that enhance immunotherapies for the treatment of human diseases.

HM71224, a novel Bruton's tyrosine kinase inhibitor, suppresses B cell and monocyte activation and ameliorates arthritis in a mouse model: a potential drug for rheumatoid arthritis

BACKGROUND

Bruton's tyrosine kinase (Btk) is critical for activation of B cells and myeloid cells. This study aimed to characterize the effects of HM71224, a novel Btk inhibitor, both in vitro and in a mouse model of experimental arthritis.

METHODS

The kinase inhibition profile of HM71224 was analyzed. The in vitro effects of HM71224 on B cells and monocytes were analyzed by examining phosphorylation of Btk and its downstream signaling molecules, along with cytokine production and osteoclast formation. The in vivo effects of HM71224 were investigated in a mouse model of collagen-induced arthritis (CIA).

RESULTS

HM71224 irreversibly bound to and inhibited Btk (IC50 = 1.95 nM). The compound also inhibited the phosphorylation of Btk and its downstream molecules such as PLCγ2, in activated Ramos B lymphoma cells and primary human B cells in a dose-dependent manner. Furthermore, HM71224 effectively inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β by human monocytes, and osteoclast formation by human monocytes. Finally, HM71224 improved experimental arthritis and prevented joint destruction in a murine model of CIA.

CONCLUSIONS

HM71224 inhibits Btk in B cells and monocytes and ameliorates experimental arthritis in a mouse model. Thus, HM71224 is a potential novel therapeutic agent for rheumatoid arthritis in humans.

Management of rheumatoid arthritis: Impact and risks of various therapeutic approaches

Rheumatic diseases are highly prevalent chronic disorders and the leading cause of physical disability worldwide, with a marked socio-economic impact. Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of unknown etiology with an autoimmune pathogenesis, characterised by arthropathy with chronic, deforming, destructive evolution and multiple systemic manifestations. The management of RA has undergone significant changes as far as objectives and approaches are concerned, ending in the current strategy known as ‘treat to target’. The therapeutic array of RA includes several categories of medicinal products, of varying potential. There are several criteria for the classification of medicinal products used against this disease, one of the most important and modern of which divides such substances according to their effects on the progress of the disease: symptom-modifying antirheumatic drugs (including non-steroidal anti-inflammatory drugs and corticoids), disease-modifying antirheumatic drugs (including various substances, such as gold salts, antimalarials, sulfasalazine, D-penicillamine; non-specific immunosuppressive medication, such as methotrexate, cyclophosphamide, azathioprine and leflunomide) and biological therapy is a recent addition, providing new insight into the treatment of this disease. The selection of the optimal therapy for RA should be based on guidelines and recommendations, but also on clinical particular aspects and patient preferences.

Experimental models of arthritis in which pathogenesis is dependent on TNF expression

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by joint damage as well as systemic manifestations. The exact cause of RA is not known. Both genetic and environmental factors are believed to contribute to the development of this disease. Increased expression of tumor necrosis factor (TNF) has been implicated in the pathogenesis of RA. Currently, the use of anti-TNF drugs is one of the most effective strategies for the treatment of RA, although therapeutic response is not observed in all patients. Furthermore, due to non-redundant protective functions of TNF, systemic anti-TNF therapy is often associated with unwanted side effects such as increased frequency of infectious diseases. Development of experimental models of arthritis in mice is necessary for studies on the mechanisms of pathogenesis of this disease and can be useful for comparative evaluation of various anti-TNF drugs. Here we provide an overview of the field and present our own data with two experimental models of autoimmune arthritis - collagen-induced arthritis and antibody-induced arthritis in C57Bl/6 and BALB/c mice, as well as in tnf-humanized mice generated on C57Bl/6 background. We show that TNF-deficient mice are resistant to the development of collagen-induced arthritis, and the use of anti-TNF therapy significantly reduces the disease symptoms. We also generated and evaluated a fluorescent detector of TNF overexpression in vivo. Overall, we have developed an experimental platform for studying the mechanisms of action of existing and newly developed anti-TNF drugs for the treatment of rheumatoid arthritis.

Internalization of rituximab and the efficiency of B Cell depletion in rheumatoid arthritis and systemic lupus erythematosus

Objective

Rituximab, a type I anti‐CD20 monoclonal antibody (mAb), induces incomplete B cell depletion in some patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), thus contributing to a poor clinical response. The mechanisms of this resistance remain elusive. The purpose of this study was to determine whether type II mAb are more efficient than type I mAb at depleting B cells from RA and SLE patients, whether internalization influences the efficiency of depletion, and whether Fcγ receptor type IIb (FcγRIIb) and the B cell receptor regulate this internalization process.

Methods

We used an in vitro whole blood B cell–depletion assay to assess the efficiency of depletion, flow cytometry to study cell surface protein expression, and surface fluorescence–quenching assays to assess rituximab internalization, in samples from patients with RA and patients with SLE. Paired t‐test or Mann‐Whitney U test was used to compare groups, and Spearman's rank correlation test was used to assess correlation.

Results

We found that type II mAb internalized significantly less rituximab than type I mAb and depleted B cells from patients with RA and SLE at least 2‐fold more efficiently than type I mAb. Internalization of rituximab was highly variable between patients, was regulated by FcγRIIb, and inversely correlated with cytotoxicity in whole blood B cell–depletion assays. The lowest levels of internalization were seen in IgD– B cells, including postswitched (IgD–CD27+) memory cells. Internalization of type I anti‐CD20 mAb was also partially inhibited by anti‐IgM stimulation.

Conclusion

Variability in internalization of rituximab was observed and was correlated with impaired B cell depletion. Therefore, slower‐internalizing type II mAb should be considered as alternative B cell–depleting agents for the treatment of RA and SLE.

CTRP6 is an endogenous complement regulator that can effectively treat induced arthritis

The complement system is important for the host defence against infection as well as for the development of inflammatory diseases. Here we show that C1q/TNF-related protein 6 (CTRP6; gene symbol C1qtnf6) expression is elevated in mouse rheumatoid arthritis (RA) models. C1qtnf6(-/-) mice are highly susceptible to induced arthritis due to enhanced complement activation, whereas C1qtnf6-transgenic mice are refractory. The Arthus reaction and the development of experimental autoimmune encephalomyelitis are also enhanced in C1qtnf6(-/-) mice and C1qtnf6(-/-) embryos are semi-lethal. We find that CTRP6 specifically suppresses the alternative pathway of the complement system by competing with factor B for C3(H2O) binding. Furthermore, treatment of arthritis-induced mice with intra-articular injection of recombinant human CTRP6 cures the arthritis. CTRP6 is expressed in human synoviocytes, and CTRP6 levels are increased in RA patients. These results indicate that CTRP6 is an endogenous complement regulator and could be used for the treatment of complement-mediated diseases.

Expansion of Activated Peripheral Blood Memory B Cells in Rheumatoid Arthritis, Impact of B Cell Depletion Therapy, and Biomarkers of Response

Although B cell depletion therapy (BCDT) is effective in a subset of rheumatoid arthritis (RA) patients, both mechanisms and biomarkers of response are poorly defined. Here we characterized abnormalities in B cell populations in RA and the impact of BCDT in order to elucidate B cell roles in the disease and response biomarkers. In active RA patients both CD27+IgD- switched memory (SM) and CD27-IgD- double negative memory (DN) peripheral blood B cells contained significantly higher fractions of CD95+ and CD21- activated cells compared to healthy controls. After BCD the predominant B cell populations were memory, and residual memory B cells displayed a high fraction of CD21- and CD95+ compared to pre-depletion indicating some resistance of these activated populations to anti-CD20. The residual memory populations also expressed more Ki-67 compared to pre-treatment, suggesting homeostatic proliferation in the B cell depleted state. Biomarkers of clinical response included lower CD95+ activated memory B cells at depletion time points and a higher ratio of transitional B cells to memory at reconstitution. B cell function in terms of cytokine secretion was dependent on B cell subset and changed with BCD. Thus, SM B cells produced pro-inflammatory (TNF) over regulatory (IL10) cytokines as compared to naïve/transitional. Notably, B cell TNF production decreased after BCDT and reconstitution compared to untreated RA. Our results support the hypothesis that the clinical and immunological outcome of BCDT depends on the relative balance of protective and pathogenic B cell subsets established after B cell depletion and repopulation.

Kinetics of hematogones in bone marrow samples from patients with non-Hodgkin lymphomas treated with rituximab-containing regimens: a flow cytometric study

Treatment with rituximab, either alone or in combination with antiblastic drugs, causes significant depletion of circulating B-lymphocytes and modifications of B cell maturation in the bone marrow. In the present study, we analyzed the kinetics of hematogones in bone marrow samples from 55 patients suffering from non-Hodgkin lymphomas and treated with rituximab-containing regimens. Maturation arrest at the level of stage 2 hematogones, along with complete depletion of naïve, mature B-lymphocytes, was observed as short-term effects (2 months after completion of chemo-immunotherapy). Further bone marrow samples, obtained 12 months after the last rituximab infusion in 21 patients undergoing long-term follow-up and treated with rituximab maintenance therapy, showed complete normalization of B-lymphocyte ontogeny. Hypogammaglobulinemia developed in 26 patients, and was still observed in nine of the 21 patients undergoing long-term follow-up. Our study provides novel data on hematogone kinetics in the setting of patients with non-Hodgkin lymphomas treated with chemo-immunotherapy containing rituximab and with rituximab maintenance. Our observations show that hypogammaglobulinemia can persist in a significant percentage of patients, despite complete recovery of B-lymphocyte ontogeny.

Severe and fatal adverse events risk associated with rituximab addition to B-cell non-Hodgkin's lymphoma (B-NHL) chemotherapy: a meta-analysis

PURPOSE

Rituximab is a monoclonal antibody targetting the CD20 antigen with the ability to increase overall remission (OR) in B-cell non-Hodgkin's lymphoma (B-NHL). A systematic review and meta-analysis were conducted to determine the risk of the most clinically relevant severe and fatal adverse events (AEs) associated with the use of rituximab in the treatment of B-NHL.

PATIENTS AND METHODS

We included phase III clinical trials that used chemotherapy in combination with rituximab or chemotherapy alone as for B-NHL. Statistical analyses were conducted to calculate summary risk ratio (RR) of the relevant severe and fatal AEs related with rituximab.

RESULTS

Eight randomised controlled clinical trials were included in this meta-analysis. Summary RR obtained showed no statistically significant rituximab-associated increased risk in 13 severe adverse events (SAEs) (infection, fever, anaemia, thrombocytopaenia, granulocytopenia, liver toxicity, cardiac toxicity, neurologic toxicity, lung toxicity, mucositis, nausea/vomiting, diarrhoea, alopecia) except leukocytopenia (36.4% versus 31%; RR = 1.13; 95%CI, 1.01-1.27; P = 0.03). The incidences of fatal AEs showed noteworthy difference between rituximab group and control group (RR = 1.45; 95% CI, 1.04-2.02; P = 0.03).

CONCLUSION

This meta-analysis indicates that there was no proof of statistically higher incidence of most SAEs in rituximab containing group compared with chemotherapy alone. However, fatal infections were more frequently observed in patients who received rituximab. Considering the low-incidence infection-induced death during the treatment period, the effects of rituximab on infections need further investigation.

Iguratimod for the treatment of rheumatoid arthritis in Japan

Iguratimod (IGU), a small-molecule compound, was developed as a disease-modifying antirheumatic drug in Japan. The pharmacological studies showed that inhibition of the production of cytokines and immunoglobulins mainly contributes to its improvement effect on animal arthritis models. The first clinical study of IGU in Japanese patients with rheumatoid arthritis was started in 1992 and Phase III studies were started in 1998. From the results of Phase II studies, a dose-escalating regimen was recommended to relieve the side effects. In a double-blind study comparing the efficacy and safety of the drug with those of placebo and salazosulfapyridine, it was confirmed that IGU was superior to placebo and was not inferior to salazosulfapyridine. Furthermore, a double-blind controlled trial of IGU in combination with methotrexate revealed an efficacious and manageable safety profile. IGU would be widely used as a new option for rheumatoid arthritis treatment and combination drug with methotrexate.

B cells expressing IFN-γ suppress Treg-cell differentiation and promote autoimmune experimental arthritis

Clinical efficacy in the treatment of rheumatoid arthritis with anti-CD20 (Rituximab)-mediated B-cell depletion has garnered interest in the mechanisms by which B cells contribute to autoimmunity. We have reported that B-cell depletion in a murine model of proteoglycan-induced arthritis (PGIA) leads to an increase in Treg cells that correlate with decreased autoreactivity. Here, we demonstrate that the increase in Treg cells after B-cell depletion is due to an increase in the differentiation of naïve CD4(+) T cells into Treg cells. Since the development of PGIA is dependent on IFN-γ and B cells are reported to produce IFN-γ, we hypothesized that B-cell-specific IFN-γ plays a role in the development of PGIA. Accordingly, mice with B-cell-specific IFN-γ deficiency were as resistant to the induction of PGIA as mice that were completely IFN-γ deficient. Importantly, despite a normal frequency of IFN-γ-producing CD4(+) T cells, B-cell-specific IFN-γ-deficient mice exhibited a higher percentage of Treg cells compared with that in WT mice. These data indicate that B-cell IFN-γ production inhibits Treg-cell differentiation and exacerbates arthritis. Thus, we have established that IFN-γ, specifically derived from B cells, uniquely contributes to the pathogenesis of autoimmunity through prevention of immunoregulatory mechanisms.

Signaling mechanisms regulating B-lymphocyte activation and tolerance

It is becoming more and more accepted that, in addition to producing autoantibodies, B lymphocytes have other important functions that influence the development of autoimmunity. For example, autoreactive B cells are able to produce inflammatory cytokines and activate pathogenic T cells. B lymphocytes can react to extracellular signals with a range of responses from anergy to autoreactivity. The final outcome is determined by the relative contribution of signaling events mediated by activating and inhibitory pathways. Besides the B cell antigen receptor (BCR), several costimulatory receptors expressed on B cells can also induce B cell proliferation and survival, or regulate antibody production. These include CD19, CD40, the B cell activating factor receptor, and Toll-like receptors. Hyperactivity of these receptors clearly contributes to breaking B-cell tolerance in several autoimmune diseases. Inhibitors of these activating signals (including protein tyrosine phosphatases, deubiquitinating enzymes and several adaptor proteins) are crucial to control B-cell activation and maintain B-cell tolerance. In this review, we summarize the inhibitory signaling mechanisms that counteract B-cell activation triggered by the BCR and the coreceptors.

Bruton's TK inhibitors: structural insights and evolution of clinical candidates

Bruton's TK (BTK) is a promising biological target for therapeutic intervention of several diseases including inflammatory diseases and cancer/B cell malignancies. Numerous research groups are actively engaged in investigating the functions of BTK, and discovering potent and selective BTK inhibitors as drug candidates. Revealed by x-ray crystal structures with ligands of diverse chemical structures, the ability of BTK kinase domain to adopt various inactive conformations offers unique opportunities to identify highly potent and exquisitely selective inhibitors. Both reversible and covalent inhibitor approaches have yielded candidates demonstrating safety profiles and efficacies in multiple preclinical models of autoimmunity and oncology. Two BTK inhibitors have entered human clinical trials for oncology indications. Ibrutinib won the US FDA approval in November 2013 to become the first-in-class BTK inhibitor for treating mantle cell lymphoma. This encouraging outcome and the other on-going human studies could ultimately expand the utility of BTK inhibitors to broader autoimmune disease areas.

Rituximab for rheumatoid arthritis

BACKGROUND

Rituximab is a selective, B-cell depleting, biologic agent for treating refractory rheumatoid arthritis (RA). It is a chimeric monoclonal antibody targeted against CD 20 that is promoted as therapy for patients who fail to respond to other biologics. There is evidence to suggest that rituximab is effective and well tolerated when used in combination with methotrexate for RA.

OBJECTIVES

To evaluate the benefits and harms of rituximab for the treatment of RA.

SEARCH METHODS

We conducted a search (until January 2014) in electronic databases (The Cochrane Library, MEDLINE, EMBASE, CINAHL, Web of Science), clinical trials registries, and websites of regulatory agencies. Reference lists from comprehensive reviews were also screened.

SELECTION CRITERIA

All controlled trials comparing treatment with rituximab as monotherapy or in combination with any disease modifying anti-rheumatic drug (DMARD) (traditional or biologic) versus placebo or other DMARD (traditional or biologic) in adult patients with active RA.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and abstracted data from each study.

MAIN RESULTS

We included eight studies with 2720 patients. For six studies selection bias could not be evaluated and two studies were considered to have low risk of bias. The level of evidence ranged from low to high, but was rated as moderate for most outcomes. We have prioritised reporting of rituximab (two 1000 mg doses) in combination with methotrexate since this is the approved dose and most commonly used combination. We also reported data on other combinations and doses as supplementary information in the results section of the review.American College of Rheumatology (ACR) 50 response rates were statistically significantly improved with rituximab (two 1000 mg doses) in combination with methotrexate compared with methotrexate alone at 24 to 104 weeks. The RR for achieving an ACR 50 at 24 weeks was 3.3 (95% CI 2.3 to 4.6); 29% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate achieved the ACR 50 compared to 9% of controls. The absolute treatment benefit (ATB) was 21% (95% CI 16% to 25%) with a number needed to treat (NNT) of 6 (95% CI 4 to 9).At 52 weeks, the RR for achieving clinical remission (Disease Activity Score (DAS) 28 joints < 2.6) with rituximab (two 1000 mg doses) in combination with methotrexate compared with methotrexate monotherapy was 2.4 (95% CI 1.7 to 3.5); 22% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate achieved clinical remission compared to 11% of controls. The ATB was 11% (95% CI 2% to 20%) with a NNT of 7 (95% CI 4 to 13).At 24 weeks, the RR for achieving a clinically meaningful improvement (CMI) in the Health Assessment Questionnaire (HAQ) (> 0.22) for patients receiving rituximab combined with methotrexate compared to patients on methotrexate alone was 1.6 (95% CI 1.2 to 2.1). The ATB was 24% (95% CI 12% to 36%) with an NNT of 5 (95% CI 3 to 13). At 104 weeks, the RR for achieving a CMI in HAQ (> 0.22) was 1.4 (95% CI 1.3 to 1.6). The ATB was 24% (95% CI 16% to 31%) with a NNT of 5 (95% CI 3 to 7).At 24 weeks, the RR for preventing radiographic progression in patients receiving rituximab (two 1000 mg doses) in combination with methotrexate was 1.2 (95% CI 1.0 to 1.4) compared to methotrexate alone; 70% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate had no radiographic progression compared to 59% of controls. The ATB was 11% (95% CI 2% to 19%) and the NNT was 10 (95% CI 5 to 57). Similar benefits were observed at 52 to 56 weeks and 104 weeks.Statistically significantly more patients achieved a CMI on the physical and mental components of the quality of life, measured by the Short Form (SF)-36, in the rituximab (two 1000 mg doses) in combination with methotrexate-treated group compared with methotrexate alone at 24 to 52 weeks (RR 2.0, 95% CI 1.1 to 3.4; NNT 4, 95% CI 3 to 8 and RR 1.4, 95% CI 1.1 to 1.9; NNT 8, 95% CI 5 to 19, respectively); 34 and 13 more patients out of 100 showed an improvement in the physical component of the quality of life measure compared to methotrexate alone (95% CI 5% to 84%; 95% CI 7% to 8%, respectively).There was no evidence of a statistically significant difference in the rates of withdrawals because of adverse events or for other reasons (that is, withdrawal of consent, violation, administrative, failure to return) in either group. However, statistically significantly more people receiving the control drug withdrew from the study compared to those receiving rituximab (two 1000 mg doses) in combination with methotrexate at all times (RR 0.40, 95% CI 0.32 to 0.50; RR 0.61, 95% CI 0.40 to 0.91; RR 0.48, 95% CI 0.28 to 0.82; RR 0.58, 95% CI 0.45 to 0.75, respectively). At 104 weeks, 37% withdrew from the control group and 20% withdrew from the rituximab (two 1000 mg doses) in combination with methotrexate group. The absolute risk difference (ARD) was -20% (95% CI -34% to -5%) with a number needed to harm (NNH) of 7 (95% CI 5 to 11).A greater proportion of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate developed adverse events after their first infusion compared to those receiving methotrexate monotherapy and placebo infusions (RR 1.6, 95% CI 1.3 to 1.9); 26% of those taking rituximab plus methotrexate reported more events associated with their first infusion compared to 16% of those on the control regimen with an ARD of 9% (95% CI 5% to 13%) and a NNH of 11 (95% CI 21 to 8). However, no statistically significant differences were noted in the rates of serious adverse events.

AUTHORS' CONCLUSIONS

Evidence from eight studies suggests that rituximab (two 1000 mg doses) in combination with methotrexate is significantly more efficacious than methotrexate alone for improving the symptoms of RA and preventing disease progression.

Small-molecule therapeutics in rheumatoid arthritis: scientific rationale, efficacy and safety

Rheumatoid arthritis (RA) remains a formidable clinical challenge. This is despite remarkable recent advances in our understanding of pathogenesis and the introduction of a variety of novel agents, particularly biologic therapeutics that are potent inhibitors of extracellular immune pathways. Whereas the latter have brought substantial improvements in efficacy and thus outcomes, there remain significant numbers of non- or partial responders to current standard of care. The discovery of key intracellular pathways, particularly kinases that subserve the function of these pivotal cytokine and immune cell receptors implicated in RA pathogenesis, has facilitated the advent of a new phase of RA drug development. Thus, a range of kinase inhibitors has entered clinical trials and one agent has been licenced for use in some regions. Herein we summarise the chequered history of kinase inhibitor development in RA, describing successes and failures alike, and thereafter examine future trends in this exciting field.

Depletion of B-cells with rituximab improves endothelial function and reduces inflammation among individuals with rheumatoid arthritis

Background

Individuals with rheumatoid arthritis (RA) are at increased risk for cardiovascular disease, partly due to systemic inflammation and endothelial dysfunction. B‐cells play an important pathogenic role in the inflammatory process that drives RA disease activity. Rituximab, a chimeric murine/human monoclonal antibody that depletes B‐cells, is an effective therapy for RA. The purpose of this study was to determine whether B‐cell depletion with rituximab reduces systemic inflammation and improves macrovascular (brachial artery flow‐mediated dilation, FMD) and microvascular (reactive hyperemia) endothelial function in RA patients.

Methods and Results

RA patients received a single course of rituximab (1000 mg IV infusion at baseline and on day 15). FMD, reactive hyperemia, inflammatory markers, and clinical assessments were performed at baseline, week 12, and week 24. Twenty patients (95% female, median age 54 years) completed the study. Following treatment, FMD improved from a baseline of 4.5±0.4% to 6.4±0.6% at 12 weeks (mean±SE; P<0.0001), followed by a decline at week 24; a similar pattern was observed for hyperemic velocity. Significant decreases in RA disease scores, high‐sensitivity C‐reactive protein, erythrocyte sedimentation rate, and circulating CD19+ B‐cells were sustained through week 24. Cholesterol and triglycerides became significantly although modestly elevated during the study.

Conclusions

Depletion of B‐cells with rituximab improved macrovascular and microvascular endothelial function and reduced systemic inflammation, despite modest elevation in lipids. Given these results, rituximab should be evaluated in the future for its possible role in reducing excess cardiovascular risk in RA.

Clinical Trial Registration

URL http://ClinicalTrials.gov. Unique identifier: NCT00844714.

Cytokine-mediated bone destruction in rheumatoid arthritis

Bone homeostasis, which involves formation and resorption, is an important process for maintaining adequate bone mass in humans. Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation and bone loss, leading to joint destruction and deformity, and is a representative disease of disrupted bone homeostasis. The bone loss and joint destruction are mediated by immunological insults by proinflammatory cytokines and various immune cells. The connection between bone and immunity has been intensely studied and comprises the emerging field of osteoimmunology. Osteoimmunology is an interdisciplinary science investigating the interplay between the skeletal and the immune systems. The main contributors in osteoimmunology are the bone effector cells, such as osteoclasts or osteoblasts, and the immune cells, particularly lymphocytes and monocytes. Physiologically, osteoclasts originate from immune cells, and immune cells regulate osteoblasts and vice versa. Pathological conditions such as RA might affect these interactions, thereby altering bone homeostasis, resulting in the unfavorable outcome of bone destruction. In this review, we describe the osteoclastogenic roles of the proinflammatory cytokines and immune cells that are important in the pathophysiology of RA.

Novel applications of Rituximab in dermatological disorders

Rituximab is a monoclonal therapeutic anti-CD20 antibody that has been approved for use in lymphoma and rheumatoid arthritis. Over the past decade several reports based on case series and observational studies have recorded the benefits of rituximab in particular groups of dermatological patients. Off-label use of rituximab in many dermatological indications is not uncommon in many countries in the world. This article reviews the available data that may be of use to the practicing dermatologist. Because of its potential complications, paucity of clinical data, and cost considerations, rituximab is favoured only when standard systemic therapies fail or corticosteroids are absolutely contraindicated. Further research is required in this field.

Autoimmune priming, tissue attack and chronic inflammation - the three stages of rheumatoid arthritis

Extensive genome-wide association studies have recently shed some light on the causes of chronic autoimmune diseases and have confirmed a central role of the adaptive immune system. Moreover, better diagnostics using disease-associated autoantibodies have been developed, and treatment has improved through the development of biologicals with precise molecular targets. Here, we use rheumatoid arthritis (RA) as a prototype for chronic autoimmune disease to propose that the pathogenesis of autoimmune diseases could be divided into three discrete stages. First, yet unknown environmental challenges seem to activate innate immunity thereby providing an adjuvant signal for the induction of adaptive immune responses that lead to the production of autoantibodies and determine the subsequent disease development. Second, a joint-specific inflammatory reaction occurs. This inflammatory reaction might be clinically diagnosed as the earliest signs of the disease. Third, inflammation is converted to a chronic process leading to tissue destruction and remodeling. In this review, we discuss the stages involved in RA pathogenesis and the experimental approaches, mainly involving animal models that can be used to investigate each disease stage. Although we focus on RA, it is possible that a similar stepwise development of disease also occurs in other chronic autoimmune settings such as multiple sclerosis (MS), type 1 diabetes, and systemic lupus erythematosus.

Rituximab (Rituxan®/MabThera®): the first decade (1993–2003)

The first antibody approved for the treatment of cancer, rituximab (Rituxan/MabThera), underwent clinical development between 1993 and 1996. It fulfilled predictions dating back to the early 1900s regarding the therapeutic effect of antibodies and sparked a renewed interest in this area of research. Rituximab was approved, in the USA in 1997 and in Europe in 1998, for the treatment of patients with non-Hodgkin's lymphoma. Since then, hundreds of thousands of patients have been treated with rituximab. In 2002, rituximab became the number one anticancer drug worldwide. During its first decade of use (1993-2003), rituximab has had an important impact on treatment strategies for lymphoma and other hematologic malignancies. During the 5 years following approval, its applications expanded beyond non-Hodgkin's lymphoma to a variety of malignant and non-malignant B-cell disorders. Also, as a result of its early clinical trials, initiatives came about that eventually led to the development of the new international response criteria for non-Hodgkin's lymphoma. Rituximab has been characterized as the most important therapeutic development of the decade.

Recent developments in the treatment of patients with systemic lupus erythematosus: focusing on biologic therapies

INTRODUCTION

Major trials hoping to obtain optimal disease control in systemic lupus erythematosus (SLE) are ongoing. Given its complex aetiology and pathogenesis, it is not surprising that multiple therapeutic targets have emerged and that none are uniformly successful.

AREAS COVERED

In this review, we highlight the recent, more significant studies focusing on the use of biologic therapies. There has been great emphasis on the role of B cells in SLE and many uncontrolled studies have encouraged the use of rituximab (an anti-CD20 monoclonal). Disappointingly, two major trials, EXPLORER and LUNAR did not confirm its utility, although doubts have been expressed on their trial design, and other trials using this drug are commencing. In contrast, belimumab, which blocks a B-cell activating factor, did meet its end points in two major randomised controlled clinical trials and has been approved for use in SLE by both the FDA and the European Medicines Agency. Encouraging, albeit preliminary, results with epratuzumab (which blocks CD22) have also been reported.

EXPERT OPINION

In addition to targeting B cells, other approaches including biologics, which modulate T-cell function and block interleukin-6 and interferon-α, have been explored. Finally, we review the recent developments in the use of conventional drugs, such as cyclophosphamide and mycophenolate.