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

The efficacy and safety of rituximab for the treatment of active rheumatoid arthritis: a systematic review and meta-analysis of randomized controlled trials

The aims of this study were to assess the efficacy and safety of rituximab in patients with active rheumatoid arthritis (RA). The authors surveyed randomized controlled trials (RCTs) that examined the efficacy of rituximab in disease modifying anti-rheumatic drug (DMARD) (including methotrexate [MTX]) or tumor necrosis factor (TNF)-blocker-resistant or intolerant patients with active RA using Medline, the Cochrane Controlled Trials Register, and manual searches. Meta-analysis of RCTs was performed to determine the treatment efficacy and safety outcomes of rituximab (1 course, consisting of two infusions of 1,000 mg each) concomitant with MTX. The three RCTs included 938 DMARD or TNF-blocker-resistant or intolerant RA patients. Follow-up periods ranged from 24 to 48 weeks. American College of Rheumatology response (ACR) 20, ACR50, and ACR70 response rates were significantly higher for the rituximab plus MTX than for placebo controls (primary efficacy outcome, ACR50; risk ratio [RR] 3.648, 95% confidence interval [CI] 2.478-5.369, P < 0.001). For those treated with rituximab, the incidence adverse events of all systems were not higher than in those treated with placebo (RR 1.062, 95% CI 0.912-1.236, P = 0.438). With respect to the number of patients that experienced at least one serious adverse event, no significant difference was observed between patients treated with rituximab and placebo (RR 0.855, 95% CI 0.622-1.174, P = 0.333). A single course of rituximab with concomitant MTX therapy was found to be effective in DMARD or TNF-blocker-resistant or intolerant patients with active RA.

B cells limit repair after ischemic acute kidney injury

There is no established modality to repair kidney damage resulting from ischemia-reperfusion injury (IRI). Early responses to IRI involve lymphocytes, but the role of B cells in tissue repair after IRI is unknown. Here, we examined B cell trafficking into postischemic mouse kidneys and compared the repair response between control (wild-type) and muMT (B cell-deficient) mice with and without adoptive transfer of B cells. B cells infiltrated postischemic kidneys and subsequently activated and differentiated to plasma cells during the repair phase. Plasma cells expressing CD126 increased and B-1 B cells trafficked into postischemic kidneys with distinct kinetics. An increase in B lymphocyte chemoattractant in the kidney preceded B cell trafficking. Postischemic kidneys of muMT mice expressed higher IL-10 and vascular endothelial growth factor and exhibited more tubular proliferation and less tubular atrophy. Adoptive transfer of B cells into muMT mice reduced tubular proliferation and increased tubular atrophy. Treatment with anti-CD126 antibody increased tubular proliferation and reduced tubular atrophy in the late repair phase. These results demonstrate that B cells may limit the repair process after kidney IRI. Targeting B cells could have therapeutic potential to improve repair after IRI.

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

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

CD19: a promising B cell target for rheumatoid arthritis

B-cell depletion with unconjugated CD20 monoclonal antibody (mAb) is used to treat rheumatoid arthritis and other autoimmune diseases. CD20-targeted immunotherapy depletes mature B cells through monocyte-mediated antibody-dependent cellular cytotoxicity, but does not effectively deplete pre-B or immature B cells, certain peripheral B cell subpopulations, most antibody-producing cells, or their malignant counterparts. As immature B cells expressing autoreactive antigen receptors are not depleted by anti-CD20 mAb, a new strategy for eliminating autoantigen-selected B cells and for treating early lymphoblastic leukemias and/or lymphomas was developed using CD19-specific mAbs that induce Fcgamma receptor-dependent and monocyte-dependent B-cell depletion. Preclinical studies using transgenic mice expressing human CD19 have shown that pre-B cells and their malignant counterparts, as well as pre-existing antibody-producing and autoantibody-producing cells, are depleted. Therefore, CD19-directed immunotherapy is expected to treat diverse pre-B-cell-related and plasmablast-related malignancies, and humoral transplant rejection. Moreover, in contrast to CD20-directed immunotherapies, CD19 mAbs could purge the B cell repertoire of autoreactive clones and reset the developmental clock to a point that curtails the extent of emerging self-reactivity, in addition to reducing autoreactive T-cell activation through the elimination of mature B cells. Humanized CD19 mAbs are expected to enter clinical trials in 2009, offering a new approach for the treatment of autoimmune disease that removes both immature B cells and antibodies with autoreactive specificities. CD19-directed immunotherapy could, therefore, offer a new horizon in B-cell depletion for the treatment of multiple autoimmune diseases.

Bioboosters in the treatment of rheumatic diseases: a comprehensive review of currently available biologics in patients with rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis

Immunologic research has clarified many aspects of the pathogenesis of inflammatory rheumatic disorders. Biologic drugs acting on different steps of the immune response, including cytokines, B- and T-cell lymphocytes, have been marketed over the past 10 years for the treatment of rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA). Randomized controlled trials (RCTs) of anti-cytokine agents in RA (including the anti-tumor necrosis factor alpha (TNFα) drugs infliximab, etanercept, adalimumab, golimumab, certolizumab, anti-interleukin (IL)-1 anakinra, and anti-IL-6 tocilizumab) demonstrated a significant efficacy compared to traditional therapies, if combined with methotrexate (MTX), as measured by ACR 20, 50 and 70 response criteria. The new therapies have also been demonstrated to be superior to MTX in slowing or halting articular damage. RCTs have shown the efficacy of anti-TNFα in AS patients through significant improvement of symptoms and function. Trials of anti-TNFα in PsA patients showed marked improvement of articular symptoms for psoriasis and radiological disease progression. More recent studies have demonstrated the efficacy of B-cell depletion with rituximab, and T-cell inactivation with abatacept. All these drugs have a satisfactory safety profile. This paper reviews the different aspects of efficacy and tolerability of biologics in the therapy of RA, AS, and PsA.

Rituximab treatment in rheumatoid arthritis: how does it work?

Treatment with the chimerical monoclonal antibody rituximab results in CD20-directed B cell depletion. Although this depletion is almost complete in the peripheral blood of nearly all patients with rheumatoid arthritis, a proportion of patients does not exhibit a clinical response. The paper by Nakou and colleagues suggests that a decrease in CD19+CD27+ memory B cells in both peripheral blood and bone marrow precedes the clinical response to rituximab. This finding adds to the emerging evidence that lack of response to rituximab is associated with persistence of B lineage cells in specific body compartments.

Efficacy of bone marrow-derived mesenchymal stem cells in the treatment of sclerodermatous chronic graft-versus-host disease: clinical report

The success of treatment for sclerodermatous chronic graft-versus-host disease (ScGVHD) remains disappointing. The immunomodulatory ability of bone marrow (BM)-derived mesenchymal stem cells (MSCs) shows promise in treating GVHD, especially given its previous success in treating patients with acute GVHD (aGVHD). The potential efficacy and safety issues for treating cGVHD, particularly ScGVHD, remain to be clarified, however. Here, we report 4 patients with ScGVHD who received MSCs expanded ex vivo from unrelated donors by intra-BM injection. After MSC infusion, the ratio of helper T lymphocyte (Th) 1 cells to Th2 cells was dramatically reversed, with an increase in Th1 and a decrease in Th2 achieving a new balance. Correspondingly, symptoms gradually improved in all 4 patients. During the course of MSC treatment, the patients' vital signs and laboratory results remained normal. At the time of this report, none of the 4 patients had experienced recurrence of leukemia. Although this study alone cannot guarantee the application of MSCs in ScGVHD, our findings strongly suggest that this treatment is therapeutically practicable, with no detectable side effects. This approach may provide new insight into the clinical treatment of ScGVHD, with the aim of greatly increasing the survival rate in patients with leukemia who undergo allogeneic BM transplantation (BMT).

Chemokine receptor expression and functional effects of chemokines on B cells: implication in the pathogenesis of rheumatoid arthritis

Introduction

Accumulation of B cells in the rheumatoid arthritis (RA) synovium has been reported, and it has been thought that these cells might contribute to the pathogenesis of RA by antigen presentation, autoantibody production, and/or inflammatory cytokine production. Chemokines could enhance the accumulation of B cells in the synovium. The aims of this study were to determine chemokine receptor expression by B cells both in the peripheral blood of normal donors and subjects with RA, and at the inflammatory site in RA, and the effects of chemokines on B cell activation.

Methods

Cell surface molecule expression was analyzed by flow cytometry. Cellular migration was assessed using chemotaxis chambers. Cellular proliferation was examined by ³H-thymidine incorporation. Tumor necrosis factor (TNF) production was assayed by enzyme-linked immunosorbent assay.

Results

Significant numbers of peripheral blood B cells of healthy donors and subjects with RA expressed CC chemokine receptor (CCR)5 and CXCR3, and most B cells expressed CCR6, CCR7, CXCR4 and CXCR5. CCR5 expression was more frequent on CD27⁺ than CD27^- peripheral blood B cells of healthy donors and RA. Synovial B cells more frequently expressed CCR5, but less often expressed CCR6, CCR7 and CXCR5 compared to peripheral blood in RA. Further functional analyses were performed on peripheral blood B cells from healthy donors. Migration of peripheral blood B cells, especially CD27⁺ B cells, was enhanced by CC chemokine ligand (CCL)20, CCL19, CCL21 and CXCL12. All four chemokines alone induced B cell proliferation; with CCL21 being the most effective. CCL21 also enhanced the proliferation of anti-immunoglobulin (Ig)M-stimulated B cells and blockade of CCR7 inhibited this effect. CCL20, CCL21 and CXCL12 enhanced TNF production by anti-IgM mAb-stimulated B cells. Finally, stimulation with CXCL12, but not CCL20, CCL19 and CCL21, enhanced inducible costimulator-ligand (ICOSL) expression by peripheral blood B cells of healthy donors and RA, but did not increase B cell-activating factor receptor or transmembrane activator and CAML-interactor.

Conclusions

The data suggest that CCR5, CCR6, CCR7, CXCR3, CXCR4 and CXCR5 may be important for the B cell migration into the synovium of RA patients, and also their local proliferation, cytokine production and ICOSL expression in the synovium.

[Anti-CD20 therapy in rheumatoid arthritis]

The anti-CD20 antibody Rituximab was the first B-cell-specific therapy approved for the treatment of rheumatoid arthritis patients. The basis for its approval in 2006 was the REFLEX study, which examined the administration of 1000 mg Rituximab at 2-week intervals combined with Methotrexat compared with placebo in patients with poor response to TNF-inhibitors in terms of all relevant clinical parameters. Radiological data show that Rituximab is capable of effectively arresting joint destruction. The treatment was well tolerated. The most common side effect, seen in up to 35% of patients, was infusion reactions, particularly during initial Rituximab administration. This could be reduced by approximately 30% with the use of steroid premedication. The serious infection rate in this randomised trial was slightly increased compared with the placebo group, as would also be expected for other biologicals. Data on re-treatment is currently available for up to five treatments and show sustained and/or improved efficacy with continued good tolerance.

Rituximab: beyond simple B cell depletion

Rituximab, a chimeric anti-CD20 monoclonal antibody, has a proven track record for over a decade in the treatment of lymphomas, where it has been used to eradicate malignant lymphocytes. In appreciation of the putative role of B cells, especially with respect to autoantibody production, in the pathogenesis of autoimmune diseases, successful trials of B-cell depletion therapy in RA, SLE, and other autoimmune diseases have been carried out. In these trials, clinical benefit has generally correlated with the extent and duration of B-cell depletion, but at times imperfectly, and autoantibody reduction only selectively. Additional mechanisms whereby rituximab may assert its clinical benefit in autoimmune diseases have been examined including a look at B-cell functions as T-cell modulator and antigen-presenting cell, T-regulatory cell behavior, NK cell activity, and macrophage activities in immune inflammation. The available data on rituximab's action in autoimmune diseases is reviewed.

Translational Mini-Review Series on B Cell-Directed Therapies: The pathogenic role of B cells in autoantibody-associated autoimmune diseases--lessons from B cell-depletion therapy

B cell depletion therapy with rituximab (BCDT) is a licensed treatment for rheumatoid arthritis and has shown promising results in the treatment of severe, refractory patients with other autoantibody-associated autoimmune diseases (AAID). The exact role that B cells play in the pathogenesis of AAID and consequently the mechanisms by which BCDT is effective are not known. The two more widely discussed hypotheses are that BCDT is effective because it removes the precursors of plasma cells producing pathogenic autoantibody species, or because it depletes a critical mass of autoreactive B cell clones that present antigen to pathogenic autoreactive T cells. This review will focus on the effects of BCDT and whether the response of patients with AAID to BCDT could be due ultimately to its effects on autoantibodies. A better knowledge of the main role that B cells play in the pathogenesis of the different diseases and a better understanding of the most likely mechanism of relapse following an earlier response to BCDT would help to guide further developments of B cell targeting therapies and potentially increase the chance of designing a protocol that could induce a long-term remission.

Anti-CD20 antibody rituximab in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, autoimmune reaction-driven systemic inflammatory disease that affects joints and several other organs. Although anti-TNF therapy and combination therapy with traditional anti-rheumatic drugs have improved the treatment of RA, still quite a significant proportion of patients do not reach adequate anti-rheumatic response. The understanding of the pathogenesis of RA has developed markedly during the last two decades, and this has brought up new targets for anti-rheumatic therapy. B cells have been found to have a pivotal role in the development of arthritis both in experimental models and in humans. Rituximab, an anti-CD20 antibody that depletes B cells, has been introduced in the treatment of RA, and it has proven to be safe and efficacious in RA. This review gives an overview on the mechanism of action of rituximab in RA and summarizes the published clinical data of rituximab in the treatment of RA.

Prolonged treatment with rituximab in patients with refractory pemphigus vulgaris

OBJECTIVES

Recent reports have documented swift responses in refractory pemphigus vulgaris to rituximab, a monoclonal anti-CD20 antibody. Nevertheless, no standard protocol has yet been established for the administration of rituximab in patients with pemphigus vulgaris. We report the results of prolonged treatment with rituximab therapy in two patients with refractory pemphigus vulgaris.

METHODS

A 22- and a 27-year-old man were diagnosed with pemphigus vulgaris according to clinical, histopathological and immunofluorescence criteria. They failed to respond after several years of steroid and immunosuppressive treatment and experienced adverse effects. Rituximab was administered intravenously at a dose of 375 mg/m2 once weekly for 4 weeks.

RESULTS

Single infusions of rituximab 375 mg/m2 were repeated at 2-monthly intervals four times because of a delayed response. The treatment was well tolerated, no side effects were observed and the previous corticosteroid therapy could be progressively withdrawn.

CONCLUSIONS

The good response of our patients suggests that rituximab may be a valuable treatment option for refractory pemphigus vulgaris. It is important that clinicians are aware that the response to rituximab in pemphigus may be delayed, and that prolonged treatment may have a good outcome.

B-cell-directed therapies for autoimmune disease

Approval of the anti-CD20 antibody rituximab for the treatment of moderate-to-severe rheumatoid arthritis in patients who fail to respond to anti-tumor-necrosis-factor agents has raised interest in B-cell-directed therapy for this disease. A number of direct and indirect modalities with distinct mechanisms of action are being investigated, including anti-CD20 and anti-CD22 therapies, and new approaches for blocking members of the tumor necrosis factor cytokine family including B cell activating factor (BAFF) and a proliferation ligand (APRIL), which are at late stages of clinical development. Clinical experience is most extensive with rituximab, and suggests that targeting 'autoimmune' memory B cells is a feasible approach for treating autoimmune disease. Although anti-CD20 therapy has only been approved for rheumatoid arthritis thus far, data suggest this approach could be valid for other autoimmune diseases, including systemic lupus erythematosus, Sjögren's syndrome, vasculitides, autoimmune cytopenias, and neurologic and dermatologic autoimmune diseases. Additional studies of direct and indirect B-cell-directed treatments are needed before we can draw conclusions as to the value of this approach in patients with various autoimmune diseases and whether more precisely defined techniques than these are required to target the complex humoral system effectively.

Ofatumumab

Ofatumumab is an anti-CD20 IgG1kappa human monoclonal antibody that is being considered by the US Food and Drug Administration and the European Medicines Agency for marketing approval as a treatment for chronic lymphocytic leukemia. The mAb is also being studied as a treatment for lymphoma, rheumatoid arthritis and multiple sclerosis. The candidate targets the same antigen as rituximab, but ofatumumab binds a novel, membrane-proximal epitope, and dissociates from its target at a slower rate compared to rituximab. Ofatumumab might be approved in the US by August 2009.

Disease activity-guided rituximab therapy in rheumatoid arthritis: the effects of re-treatment in initial nonresponders versus initial responders

OBJECTIVE

To explore the efficacy of re-treatment with rituximab in patients with rheumatoid arthritis (RA) who were initial nonresponders to treatment, and to evaluate the effects of rituximab in RA when re-treatment is given in a standardized way based on the Disease Activity Score in 28 joints (DAS28), according to the international consensus statement.

METHODS

Patients with RA who had a DAS28 of > or =3.2 received up to 3 courses of rituximab at intervals of at least 6 months, regardless of whether the patient had responded to the first course of treatment with rituximab.

RESULTS

Of the 30 patients with RA who were included in the study, 26 could be evaluated for the efficacy of treatment after 6 months. Eighteen patients qualified for re-treatment at 6 months, 6 patients were re-treated at a later time point because of a disease relapse, and 2 other patients were not re-treated because they had low disease activity. Seven of the 24 patients who qualified for re-treatment had not exhibited clinical improvement after the first treatment course. These patients typically did not respond to subsequent courses of rituximab. Of interest, in the 17 patients who had exhibited a clinical response to the first course of rituximab, the second and third treatment courses resulted in European League Against Rheumatism responses similar to those observed after the first course, and no major relapses occurred before re-treatment.

CONCLUSION

Rituximab re-treatment is not effective in patients who do not exhibit clinical improvement after the first treatment course, which is consistent with the notion that such patients represent a different pathogenetic subset of RA. Patients who initially responded to rituximab treatment experienced sustained benefit from DAS28-based systematic re-treatment according to the international consensus statement.

Long term treatment of rheumatoid arthritis with rituximab

B cells play an important role in the pathogenesis of rheumatoid arthritis (RA). Rituximab is a chimeric monoclonal antibody that depletes B-cells by binding to the CD20 surface antigen that has been approved for the treatment of RA. Its efficacy has been clearly demonstrated by different clinical trials and, recently, in long-term observational studies. The use of rituximab in clinical practice has highlighted its efficacy and safety over more than 5 years of treatment, as well as to try to understand the timing for retreatment of patients relapsing after a good initial response.

Critical analysis of rituximab-induced serological changes in connective tissue diseases

A survey of PUBMED and EMBASE supplied 21 articles dealing with the effect of rituximab (RTX) on immunoglobulin (Ig) and autoantibodies (Abs) in nonorgan-systemic autoimmune diseases, and another 12 articles were found by hand search. No statistics could be performed due to the lack of numerical data in the articles. RTX tended to diminish total Ig but still within the normal ranges, more for IgM than IgG and IgA. Rheumatoid factor level decreased by 30 to 60% 3-6 months after RTX, whereas anti-cyclic citrullinated peptide Ab titers declined modestly. In contrast, anti-DNA and anti-C1q Ab levels showed a marked decrease, whereas the other anti-extractable nuclear antigens Ab (anti-SSA, SSB, SM, RNP...) were stable. There are claims for an increase in the BAFF level by approximately 2.5 to 3-fold at 3-4 months, and a return to pre-treatment value at 8-12 months. RTX-induced changes in the serum bring about new insights into mechanisms of action. Therefore, more attention should be paid to such parameters in clinical trials.

Frequency of regulatory T cells is not affected by transient B cell depletion using anti-CD20 antibodies in rheumatoid arthritis

Objectives

Transient B cell depletion with the monoclonal anti-CD20 antibody rituximab has shown favourable clinical responses in patients with rheumatoid arthritis (RA). Recently a characteristic regeneration pattern of B cell subpopulations has been reported. However, little is known about the impact of B-cell depletion on peripheral T cells in particular regulatory T cells.

Materials and Methodology

17 patients with RA having failed anti-TNF were treated with rituximab. Four colour staining was performed using CD19, CD3, CD4, CD8, CD16, CD56, CD25, HLA-DR, HLA-G and intracellular Foxp3 at five time points spanning up to 12 months after rituximab. In addition, quantification of the soluble form of the HLA class I molecule HLA-G by ELISA has been performed.

Results

Peripheral B cell depletion lasted 6 to 9 months. The absolute number of CD3+, CD4+ and CD8+ lymphocytes showed no significant changes up to 1 year after B-cell depletion compared to before therapy. Only the relative frequency for CD3 and CD4 showed a significant increase (p < 0.05). In particular, CD4+CD25++ and Foxp3 positive regulatory T cells remained constant. The percentage of HLA-G positive cells in the CD4+ or CD8+ population did not change significantly either. The amount of sHLA-G remained without significant changes.

Conclusion

Absolute T cell counts showed no significant changes after rituximab compared to the time point before therapy.In particular, the frequency of regulatory T cells with a CD4+CD25++ phenotype as well as positive Foxp3 expression were numerically stable. Additionally, HLA-G positive regulatory T cells and soluble levels of HLA-G showed no significant changes.

Rituximab therapy in Greek patients with rheumatoid arthritis

OBJECTIVE

An open-label, prospective, uncontrolled study created to investigate clinical response, serological changes and side effects in Greek patients with rheumatoid arthritis (RA), after B-cell depletion with rituximab.

METHODS

Patients with high disease activity (disease activity score [DAS]-28 > 5.1) were selected for treatment with rituximab and received two infusions, 1 gr each, 2 weeks apart. Different disease parameters (visual analog scale, DAS-28, C-reactive protein [CRP], erythrocyte sedimentation rate, health assessment questionnaire, complement (C3), C4, rheumatoid factor [RF], anti-cyclic citrullinated peptide antibody [anti-CCP], swollen joint count, tender joint count, immunoglobulin M [IgM], IgG, IgA) were performed at base line, 2, 4, and 6 months post-treatment. Response was defined according to the American College of Rheumatology (ACR) criteria.

RESULTS

Seventeen patients received therapy. Treatment led to a reduction in various disease parameters. ACR20 was achieved in 41.11% of patients by week 8, 52.94% by week 16, and 82.35% by week 24. ACR50 was achieved in 5.88% by week 8, 41.17% by week 16, and 64.7% by week 24. ACR70 was achieved only by week 24 in 23.52% of patients. Statistical analysis has shown no differences in clinical response, between RF positive/negative patients, and anti-CCP-positive/negative patients, while decline of RF was better correlated with reduction of DAS-28 than with anti-CCP.

CONCLUSIONS

Rituximab is a well tolerated and effective treatment in RA. Response was not correlated to RF or anti-CCP positivity. Decline of RF was associated with clinical response and reduction of DAS-28 and CRP.

Regulatory B cells inhibit EAE initiation in mice while other B cells promote disease progression

EAE is a mouse T cell-mediated autoimmune disease of the CNS used to model the human condition MS. The contributions of B cells to EAE initiation and progression are unclear. In this study, we have shown that EAE disease initiation and progression are differentially influenced by the depletion of B cells from mice with otherwise intact immune systems. CD20 antibody-mediated B cell depletion before EAE induction substantially exacerbated disease symptoms and increased encephalitogenic T cell influx into the CNS. Increased symptom severity resulted from the depletion of a rare IL-10-producing CD1dhiCD5+ regulatory B cell subset (B10 cells), since the adoptive transfer of splenic B10 cells before EAE induction normalized EAE in B cell-depleted mice. While transfer of regulatory B10 cells was maximally effective during early EAE initiation, they had no obvious role during disease progression. Rather, B cell depletion during EAE disease progression dramatically suppressed symptoms. Specifically, B cells were required for the generation of CD4+ T cells specific for CNS autoantigen and the entry of encephalitogenic T cells into the CNS during disease progression. These results demonstrate reciprocal regulatory roles for B cells during EAE immunopathogenesis. The therapeutic effect of B cell depletion for the treatment of autoimmunity may therefore depend on the relative contributions and the timing of these opposing B cell activities during the course of disease initiation and pathogenesis.

Effects of rituximab on morphofunctional abnormalities of membranous glomerulopathy

BACKGROUND AND OBJECTIVES

In idiopathic membranous nephropathy (IMN), CD(20) B-cell depletion by rituximab may induce nephrotic syndrome (NS) remission. Whether this is associated with kidney function restoration and regression of the glomerular pathology was evaluated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Treatment-induced morphofunctional changes were evaluated in 7 IMN patients consenting to repeat functional and morphologic evaluations after stable disease remission achieved by four weekly rituximab (375 mg/m(2)) infusions.

RESULTS

Over a median of 21 mo from rituximab administration, NS remission was associated with 8.5-fold increase versus baseline in sodium fractional clearance from 1.56 to 13.25, decrease in renal plasma flow from 440.8 to 276.6 ml/min per 1.73 m(2), stable glomerular filtration rate, and increased renal vascular resistances. Changes in sodium fractional clearance and hemoglobin concentration were positively correlated (r = 0.82). Biopsy reevaluations showed complete or partial reabsorption of subepithelial deposits. Median (interquartile range) IgG4 staining score decreased from 3 (3-3) to 1 (0-2), whereas total numbers of slit diaphragms (0.27; range, 0.19 to 0.30 versus 0.86; range, 0.53 to 1.16 slits/mum glomerular basement membrane) and percentages of those with electron-dense diaphragm (55.2; range, 42.0 to 62.0 versus 78.5; range, 73.0 to 82.7 of all slits) significantly increased in parallel with amelioration of glomerular ultrastructural changes. Changes in slit frequency and albumin fractional clearance were negatively correlated (r = -0.79).

CONCLUSIONS

In human IMN, treatment-induced NS remission is associated with restoration of sodium homeostasis and kidney hemodynamics, and regression of the glomerular changes underlying proteinuria. These effects are likely to translate into long-term renoprotection.

Improvement in patient-reported outcomes in a rituximab trial in patients with severe rheumatoid arthritis refractory to anti-tumor necrosis factor therapy

OBJECTIVE

To assess the effects of treatment with rituximab plus methotrexate on patient-reported outcomes in patients with active rheumatoid arthritis (RA) who experienced inadequate response to anti-tumor necrosis factor therapy.

METHODS

Patients with active RA were randomly assigned to rituximab (1,000 mg on days 1 and 15) or placebo. The primary end point was the proportion of patients with an American College of Rheumatology 20% response at week 24. Additional goals were to assess treatment effects on pain, fatigue, functional disability, health-related quality of life, and disease activity by comparing mean changes between groups. The analysis was conducted in the intent-to-treat population. The proportion of patients who achieved the minimum clinically important difference on the Health Assessment Questionnaire (HAQ) disability index (DI), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), and Short Form 36 (SF-36) was determined.

RESULTS

Rituximab patients had statistically significantly greater pain relief. The FACIT-F showed significantly greater improvement in rituximab patients than placebo patients from weeks 12 through 24. Mean improvement from baseline in functional disability (measured by the HAQ DI) was significantly greater in rituximab patients from weeks 8 to 24. The mean +/- SD change from baseline for the SF-36 Physical Component Score was 6.64 +/- 8.74 for rituximab patients and 1.48 +/- 7.32 for placebo patients (P < 0.0001). The mean change from baseline for the SF-36 Mental Component Score was 5.32 +/- 12.41 for rituximab patients and 2.25 +/- 12.23 for placebo patients (P = 0.0269).

CONCLUSION

Rituximab produced rapid, clinically meaningful, and statistically significant improvements in patient-reported pain, fatigue, functional disability, health-related quality of life, and disease activity. These effects were sustained throughout the study.

B-cells and humoral immunity in multiple sclerosis. Implications for therapy

B-cells and humoral immunity have been implicated in the pathogenesis of multiple sclerosis. The most common pattern of demyelinating pathology in multiple sclerosis is associated with the deposition of antibodies and the activation of complement, as well as T-cells and macrophages. Plasmapheresis has been found to be an efficient therapeutic approach in patients with this type of pathological lesion. Recent data have indicated that autoantibodies and complement C5b-9 may be involved in lesion formation and might also be beneficial for lesion repair. Thus, the role played by B-cells and humoral immunity is rather complex, and new strategies for targeting B-cell responses are continuing to emerge.

Immunity to citrullinated proteins in rheumatoid arthritis

Antibodies to citrullinated proteins (ACPA), i.e., to peptides posttranslationally modified by the conversion of arginine to citrulline, are specific serological markers for rheumatoid arthritis (RA). Studies on anticitrulline immunity, summarized in this review, demonstrate that the criterion-based syndrome RA should be subdivided into at least two distinct subsets (ACPA-positive and ACPA-negative disease). A new etiological model is proposed for ACPA-positive RA, built on MHC class II-dependent activation of adaptive immunity. Fundamentals of this model include the following: (a) ACPA antedate onset of arthritis; (b) ACPA may aggravate arthritis in rodents; (c) ACPA are triggered in the context of genes that confer susceptibility to RA (HLA-DRB1 SE) and by environmental agents triggering RA (smoking or bacterial stimuli); (d) ACPA may complex with citrullinated proteins present in target tissue as part of a multistep process for arthritis development. The model provides a new basis for molecular studies on the pathogenesis of ACPA-positive arthritis.

The role of collagen antibodies in mediating arthritis

This review examines evidence that rheumatoid arthritis (RA) depends on autoimmunity to articular collagen, and mechanisms whereby autoantibodies to type II collagen contribute to disease development. Three major autoantigenic reactants have been identified in RA; the corresponding autoantibodies are rheumatoid factor (RF), antibodies to citrullinated peptide antigens (ACPA), citrullinated peptides (anti-CCP), and anti-type II collagen (anti-CII). Both RF and ACPA are well-validated and predictive markers of severe erosive RA, but cannot be linked to pathogenesis. By contrast, in various animal species immunized with CII there occurs an erosive inflammatory arthritis resembling that seen in human RA, together with antibodies to CII with an epitope specificity similar to that in RA. We discuss the well-known role of immune complexes in the induction of inflammation within the joint, and present recent data showing, additionally, that antibodies to CII cause direct damage to cartilage in vitro. The close resemblances between human RA and collagen-induced arthritis in animals suggest that autoimmunity, and particularly autoantibodies to CII, are important for both the initiation and perpetuation of RA in a dual manner: as contributors to the inflammation associated with immune complex deposition, and as agents with direct degradative effects on cartilage integrity and its repair.

Destructive arthritis in the absence of both FcgammaRI and FcgammaRIII

Fc receptors for IgG (FcgammaR) have been implicated in the development of arthritis. However, the precise contribution of the individual FcgammaR to joint pathology is unclear. In this study, the role of the different FcgammaR was assessed both in an active and in a passive mouse model of arthritis by analyzing disease development in double and triple knockout (KO) offspring from crosses of FcgammaRI KO, FcgammaRIII KO, FcgammaRI/III double KO, or FcR gamma-chain KO with the FcgammaRII KO on C57BL6 background, which is susceptible for collagen-induced arthritis (CIA). In the active CIA model, onset was significantly delayed in the absence of FcgammaRIII, whereas incidence and maximum severity were significantly decreased in FcgammaRI/II/III triple KO but not in FcgammaRII/III double KO and FcgammaRI/II double KO mice as compared with FcgammaRII KO animals. Remarkably, fully destructive CIA developed in FcgammaRI/II/III triple KO mice. In contrast, FcR gamma/FcgammaRII double KO mice were resistant to CIA. These findings were confirmed with the passive KRN serum-induced arthritis model. These results indicate that all activating FcgammaR play a role in the development of arthritis, mainly in the downstream effector phase. FcgammaRIII is critically required for early arthritis onset, and FcgammaRI can substantially contribute to arthritis pathology. Importantly, FcgammaRI and FcgammaRIII were together dispensable for the development of destructive arthritis but the FcR gamma-chain was not, suggesting a role for another FcR gamma-chain associated receptor, most likely FcgammaRIV. In addition, FcgammaRII plays a negative regulatory role in both the central and effector phase of arthritis.

The development of targeted therapies in rheumatoid arthritis

The therapy of rheumatoid arthritis has been revolutionised by advances in the understanding of disease at a cellular and molecular level accompanied by the technology to target specific mediators of disease. Proposed therapeutic targets from in vitro and animal models however have frequently resulted in unexpected outcomes in clinical trials. These have included have included cytokines, chemokines, the T cell receptor trimolecular complex, T cells and B cells. The most successful strategies have resulted from a close dialogue between clinical and laboratory work. The key stages in the development of these agents and remaining unanswered questions are reviewed.

Targeted B-cell depletion therapy in childhood-onset systemic lupus erythematosus: progress to date

Childhood-onset systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease associated with significant morbidity and mortality with lupus nephritis being a major prognostic factor. Children with SLE tend to have more severe hematologic and renal involvement compared with adults. Although the morbidity and mortality have greatly improved over the last 20 years, recent studies show that there are still associated major risks from under treatment (with resultant severe flares of disease activity) and over treatment (with additional medication adverse effects including risks of severe infection; many of these patients have inherent abnormal complement pathways). Therapies used to treat children with SLE need to be individualized based on multiorgan involvement, severity of disease, history of disease flares, and knowledge of recent relevant clinical, hematologic, and immunologic parameters. These medications need to be the most effective treatments, allowing normal growth, development, fertility, and the avoidance of severe toxicity and future malignancies. Many toxic effects of current medications range from the well described Cushingoid features of corticosteroids to the gastrointestinal adverse effects of mycophenolate mofetil. In vitro studies have shown that rituximab causes B-cell depletion by mechanisms involving antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, and direct signaling leading to apoptosis. As the adverse effect profile of B-cell depletion with rituximab has been well described in adults and children with oncologic and other autoimmune diseases, initial pilot studies using rituximab in patients with refractory SLE have been carried out according to different protocols. Evidence to date in open studies demonstrates that targeted B-cell depletion therapy can be safe and efficacious as an addition to standard immunosuppressant agents in refractory childhood-onset and adult-onset disease. Although there are positive outcomes in using this therapy, caution is necessary with respect to minimizing the number of doses and treatments given to reduce the incidence of developing human anti-chimeric antibodies. The next phase for the clinical and research community are multicenter randomized controlled trials of rituximab in severe childhood SLE, such as a comparative trial of rituximab versus intravenous cyclophosphamide in patients both at presentation and with exacerbations of disease activity.

Rituximab for the treatment of rheumatoid arthritis

Rituximab has been approved by the United States Food and Drug Administration in combination with methotrexate for the treatment of rheumatoid arthritis in patients who failed to achieve adequate benefit from tumor necrosis factor-alpha inhibitors. Rituximab is a biologic agent that depletes peripheral B cells--an action thought to reduce rheumatoid arthritis activity--and induces prolonged clinical improvement. Two 1000-mg infusions administered 2 weeks apart can result in a response that lasts for months. Most patients will require retreatment, but the effect of repeated dosing on patient outcomes has not yet been determined. Combination therapy with methotrexate is recommended as this appears to achieve the best outcomes. Rituximab also has been shown to be safe, although the lack of long-term efficacy and safety data limit its use. More studies are needed, but this agent has been demonstrated to be safe and effective in patients who fail to achieve adequate clinical response to methotrexate and tumor necrosis factor-alpha inhibitors.

Safety and efficacy of additional courses of rituximab in patients with active rheumatoid arthritis: an open-label extension analysis

OBJECTIVE

To determine the safety and efficacy of additional courses of rituximab in patients with rheumatoid arthritis (RA).

METHODS

An open-label extension analysis of RA patients previously treated with rituximab was conducted. Patients who had participated in any of 3 double-blind trials were eligible for additional courses (2 infusions of 1,000 mg given 2 weeks apart) if they exhibited a swollen joint count and tender joint count of > or =8 with > or =16 weeks elapsing after the previous course. Safety was assessed in patients receiving all or a portion of a rituximab course. Efficacy was assessed 24 weeks after each course, using the American College of Rheumatology 20% criteria for improvement (ACR20), ACR50, ACR70, European League Against Rheumatism (EULAR) response criteria, Disease Activity Score in 28 joints, the disability index of the Health Assessment Questionnaire, and Short Form 36 scores, stratified according to prior tumor necrosis factor (TNF) inhibitor exposure.

RESULTS

A total of 1,039 patients received > or =1 course of rituximab. Of these, 570 received 2 courses, 191 received 3 courses, and 40 received 4 courses, for a total of 1,669 patient-years. Irrespective of prior TNF inhibitor exposure, ACR20 responses were comparable at week 24 after course 1 and at week 24 after course 2 (65% versus 72%), as were ACR50 and ACR70 responses. EULAR moderate/good responses were also comparable in course 2 relative to course 1 (88% versus 79%), with EULAR remission occurring in a 2-fold higher proportion of patients after course 2 than after course 1 (13% versus 6%). The most common adverse events, which were mild-to-moderate acute infusion-related events, decreased with each course. The serious infection rate after course 1 (5.1 per 100 patient-years) remained stable through additional courses. The proportion of patients with circulating IgM and IgG levels below the lower limit of normal (LLN) increased with subsequent courses; however, serious infection rates in these patients (5.6 per 100 patient-years in patients with low IgM levels and 4.8 per 100 patient-years in patients with low IgG levels were comparable with those in patients with immunoglobulin levels above the LLN (4.7 per 100 patient-years). Patients with human antichimeric antibody (9.2%) did not exhibit decreasing efficacy or present additional safety concerns.

CONCLUSION

These findings indicate that patients treated with repeated courses of rituximab have sustained clinical responses with no new adverse events.

Rituximab: in rheumatoid arthritis

An important role for B cells in the immunopathogenesis of rheumatoid arthritis (RA) is recognized. Rituximab is a chimeric murine/human anti-CD20 monoclonal antibody that transiently depletes CD20+ B cells. A single course of rituximab (two intravenous infusions of 1,000mg given two weeks apart) with a stable dose of methotrexate significantly improved all measures of disease activity, fatigue, and health-related quality of life relative to placebo with methotrexate. This was demonstrated in the REFLEX trial, a 24-week, randomized, double-blind, double-dummy, international, phase III study in 520 patients who had active RA despite ongoing treatment with methotrexate and had experienced an inadequate response to anti-tumor necrosis factor (TNF) therapy. Patients in REFLEX (or other studies) who responded to, and required further treatment after, an initial course of rituximab continued to respond to subsequent courses of the drug. A small subgroup of patients in REFLEX continued to respond to their first course of rituximab through 48 weeks of follow-up. Long-term treatment (up to 56 weeks) with one or more courses of rituximab in REFLEX significantly inhibited joint structural damage, the first time this effect has been reported in patients with an inadequate response to TNF inhibitors. Rituximab was generally well tolerated; the majority of adverse events were related to the first infusion of the drug, were mild to moderate in severity, and were easily managed. The adverse event profile of rituximab was unchanged after repeat courses.

The potential utility of B cell-directed biologic therapy in autoimmune diseases

Increasing awareness of the importance of aberrant B cell regulation in autoimmunity has driven the clinical development of novel B cell-directed biologic therapies with the potential to treat a range of autoimmune disorders. The first of these drugs-rituximab, a chimeric monoclonal antibody against the B cell-specific surface marker CD20-was recently approved for treating rheumatoid arthritis in patients with an inadequate response to other biologic therapies. The aim of this review is to discuss the potential use of rituximab in the management of other autoimmune disorders. Results from early phase clinical trials indicate that rituximab may provide clinical benefit in systemic lupus erythematosus, Sjögren's syndrome, vasculitis, and thrombocytopenic purpura. Numerous case reports and several small pilot studies have also been published reporting the use of rituximab in conditions such as myositis, antiphospholipid syndrome, Still's disease, and multiple sclerosis. In general, the results from these preliminary studies encourage further testing of rituximab therapy in formalized clinical trials. Based on results published to date, it is concluded that rituximab, together with other B cell-directed therapies currently under clinical development, is likely to provide an important new treatment option for a number of these difficult-to-treat autoimmune disorders.

Anti-CD20 monoclonal antibody in rheumatoid arthritis and systemic lupus erythematosus

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are both chronic autoimmune rheumatic diseases. In the last few years, evolution in the understanding of RA and SLE pathogenesis and underlying molecular mechanisms has resulted in development and availability of novel therapies. In particular, the recent acknowledgement of a more significant role for B cells in the pathogenesis of RA, in contrast to the view that it was predominantly a T cell disorder, provided rationale for trials of B cell depletion therapy with the chimeric anti-CD20 monoclonal antibody rituximab. The efficacy and favourable safety profile of rituximab have resulted in the recent approval by the European Medicines Agency for its usage in patients with RA unresponsive to conventional therapies. The salient features from the pivotal open and randomised controlled trials are reviewed in this chapter. Given the recognition of B cell dysfunction as central to SLE pathogenesis, the use of anti-CD20 antibody therapy for this patient group has also been established. Results of the open trials have been encouraging, particularly in patients not responding to usual therapies, and a randomised controlled trial is underway.