Efficacy of B-cell-targeted therapy with rituximab in patients with rheumatoid arthritis

[Modern antirheumatic pharmacotherapy. Low molecular weight substances vs. biologicals]

Rheumatoid arthritis potentially causes joint destruction, organ failures, and accompanying disorders. Therefore initiating therapeutic measures as early as possible is crucial, whereby symptomatic treatment only is definitely insufficient. Among the traditional disease-modifying antirheumatic drugs (DMARD) Methotrexate is regarded the gold standard. Increasing knowledge of cell-interactions, particularly of the cytokine-cascade, resulted in new therapeutic options. Direct impact via "biologicals" on key inflammatory mediators, primarily TNF-alpha, offers the possibility of effectively modulating or even arresting disease progression. Nowadays, those substances are applied in non-responders to traditional DMARD. Despite their benefits, cons like an increased risk for infections, for exacerbating latent tuberculosis and possibly for malignancies must be considered. Thus, a thorough patient check-up before initiating these therapies is mandatory. Pharmacoeconomic aspects influence the discussion about these "new therapies". The high costs of biologicals, however, should be related to the possible reduction of the diseases psychological, social and economic burdens.

Antirheumatic Drugs in Pregnancy and Lactation

OBJECTIVE

To review the toxicity issues of commonly used antirheumatic drugs in pregnancy and lactation.

METHODS

A review of the medical literature using Medline database via Ovid was performed to identify the toxicities of antirheumatic drugs in pregnancy and lactation.

RESULTS

Many rheumatologic diseases in women often first present during the childbearing years. In most cases, antirheumatic therapy is required for their disease control. Glucocorticoids may be used during pregnancy; however, first-trimester use should be avoided if possible and breastfeeding should occur 4 hours after the last dosing. Nonsteroidal antiinflammatory drugs (NSAIDs) and cyclooxygenase-2 (COX-2) inhibitors should be discontinued 6 to 8 weeks before delivery. NSAIDs are compatible with lactation, although there is potential risk of jaundice and kernicterus. There is insufficient data on COX-2 inhibitors and lactation. Hydroxychloroquine and sulfasalazine may be continued throughout pregnancy and lactation. Methotrexate and leflunomide are contraindicated during pregnancy and lactation. Cyclophosphamide and mycophenolate mofetil should be avoided during pregnancy and lactation. Azathioprine and cyclosporine A could be used with caution during pregnancy if felt there is a need to suppress disease activity. They are not compatible with breastfeeding. There are insufficient data regarding tumor necrosis factor-antagonists, anakinra, and rituximab in relation to pregnancy and lactation. Male patients should be made aware of the effects methotrexate, leflunomide, sulfasalazine, and cyclophosphamide may have on their fertility.

CONCLUSIONS

Health care providers should discuss the risks and benefits of antirheumatic therapy during conception, pregnancy, and lactation with their patients. Better maternal and fetal outcomes can be expected if the pregnancy is planned, the rheumatic disease is stable, and if appropriate medication adjustments can be made ahead of time.

B-cell depletion in the treatment of patients with systemic lupus erythematosus: a longitudinal analysis of 24 patients

OBJECTIVES

To assess the clinical and basic serological consequences of B-cell depletion with rituximab in the treatment of patients with systemic lupus erythematosus (SLE) who have failed conventional immunosuppression.

METHODS

An open study of 24 patients with severe SLE followed for a minimum of 3 months is reported. In the majority of patients (19 out of 24), 6 months follow-up data are described. Disease activity in these patients was assessed every 1-2 months using the British Isles Lupus Assessment Group (BILAG) system and estimates of anti-double-stranded DNA antibodies and serum C3 levels. During the follow-up period, significant side-effects were sought and the reduction in oral prednisolone was recorded. It was our general practice to stop concomitant immunosuppression (e.g. azathioprine, mycophenolate) when B-cell depletion was given (in most cases in the form of two 1 g intravenous infusions of rituximab 2 weeks apart accompanied by two 750 mg intravenous cyclophosphamide infusions and two methylprednisolone infusions of 250 mg each).

RESULTS

Twenty-two patients were female and two male. At the time of B-cell depletion, the mean age was 28.9 yr (range 17-49) and the mean disease duration was 7.9 yr (range 1-18). The global BILAG score (P < 0.00001), serum C3 (P < 0.0005) and double-stranded DNA binding (P < 0.002) all improved from the time of B-cell depletion to 6 months after this treatment. Only one patient failed to achieve B-lymphocyte depletion in the peripheral blood. The period of B-lymphocyte depletion ranged from 3 to 8 months except for one patient who remains depleted at more than 4 yr. Analysis of the regular BILAG assessments showed that improvements occurred in each of the eight organs or systems. The mean daily prednisolone dose fell from 13.8 mg (s.d. 11.3) to 10 mg (s.d. 3.1).

CONCLUSION

In this open study of patients who had failed conventional immunosuppressive therapy, considerable utility in the use of B-cell depletion has been demonstrated. Our data provide strong support for the performance of a full double-blind control trial.

Antibody-mediated organ-allograft rejection

Recent studies show that alloantibodies mediate a substantial proportion of graft-rejection episodes, contributing to both early and late graft loss. Rejection that is caused by antibody is mediated by different mechanisms from rejection that is caused by T cells, thereby requiring other approaches to treatment and prevention. Antibody induces rejection acutely through the fixation of complement, resulting in tissue injury and coagulation. In addition, complement activation recruits macrophages and neutrophils, causing additional endothelial injury. Antibody and complement also induce gene expression by endothelial cells, which is thought to remodel arteries and basement membranes, leading to fixed and irreversible anatomical lesions that permanently compromise graft function.

The therapeutic potential of anti-CD20 "what do B-cells do?"

B-cells play a major role in the immunopathogenesis of autoimmune diseases. Not only do they produce autoantibodies, but they regulate other cell types, secrete cytokines, and present antigens. They are thus potential targets for therapeutic intervention. CD20 is a B-cell specific cell surface molecule of uncertain function. An anti-CD20 chimeric mAb (rituximab) has been FDA approved for treatment of B-cell lymphomas since 1997. Rituximab also depletes normal B-cells by several mechanisms, including ADCC. Over the past seven years, it has shown promise in a number of autoimmune diseases in phase I trials and anecdotal reports. Efficacy in rheumatoid arthritis has already been demonstrated in randomized control trials (RCTs), and RCTs in SLE, inflammatory myositis, and ANCA associated vasculitis are under way. Safety does not appear to be a major problem, but continued vigilance is warranted. The increased use of rituximab, other anti-CD20 agents, and other B-cell targeting therapies holds great promise for substantial clinical benefits, as well as providing special opportunities to understand better disease pathogenesis.

Activating and inhibitory IgG Fc receptors on human DCs mediate opposing functions

Human monocyte-derived DCs (moDCs) and circulating conventional DCs coexpress activating (CD32a) and inhibitory (CD32b) isoforms of IgG Fcgamma receptor (FcgammaR) II (CD32). The balance between these divergent receptors establishes a threshold of DC activation and enables immune complexes to mediate opposing effects on DC maturation and function. IFN-gamma most potently favors CD32a expression on immature DCs, whereas soluble antiinflammatory concentrations of monomeric IgG have the opposite effect. Ligation of CD32a leads to DC maturation, increased stimulation of allogeneic T cells, and enhanced secretion of inflammatory cytokines, with the exception of IL-12p70. Coligation of CD32b limits activation through CD32a and hence reduces the immunogenicity of moDCs even for a strong stimulus like alloantigen. Targeting CD32b alone does not mature or activate DCs but rather maintains an immature state. Coexpression of activating and inhibitory FcgammaRs by DCs reveals a homeostatic checkpoint for inducing tolerance or immunity by immune complexes. These findings have important implications for understanding the pathophysiology of immune complex diseases and for optimizing the efficacy of therapeutic mAbs. The data also suggest novel strategies for targeting antigens to the activating or inhibitory FcgammaRs on human DCs to generate either antigen-specific immunity or tolerance.

B cell depletion in autoimmune rheumatic diseases

Rituximab is a chimeric mouse-human monoclonal antibody, which binds to CD20, a B cell surface marker, leading to cell death by complement induced lysis and apoptosis. Since the introduction of this drug in the treatment of non-Hodgkin lymphoma, its applications have been extended to autoimmune diseases. This review summarizes the actual possible uses of this novel immune system targeted drug, and explains the mechanism of B cell depletion in autoimmune diseases.

Emerging biologic therapies in rheumatoid arthritis: cell targets and cytokines

PURPOSE OF REVIEW

Biologic therapy for rheumatoid arthritis targets specific molecules, both cell-bound and soluble, that mediate and sustain the clinical manifestations of this complex disease. The aim of all the therapeutic strategies is to achieve complete and sustained suppression of inflammation, in the absence of unacceptable short-term and long-term toxicity. Despite the success of the currently available biologic inhibitors of tumor necrosis factor-alpha and interleukin-1, a substantial number of rheumatoid arthritis patients are refractory to these treatments. The purpose of this review is to highlight recent clinical trials of emerging biologic treatments for rheumatoid arthritis.

RECENT FINDINGS

T cell co-stimulation has been targeted by the use of cytotoxic T lymphocyte-associated antigen 4-Ig, a genetically engineered fusion protein. In a large controlled clinical trial, this nondepleting approach was shown to achieve impressive clinical responses, without evidence of short-term toxicity. Likewise, rituximab, a B cell-deleting monoclonal antibody, was shown in a controlled clinical trial to have sustained benefit in patients with refractory rheumatoid arthritis. Despite profound B cell depletion with rituximab, there was an acceptable safety profile with this treatment. MRA, a monoclonal antibody that inhibits interleukin-6 by binding to its receptor interleukin-6R, demonstrated clinically significant improvement in rheumatoid arthritis and a particularly impressive reduction in the acute phase response.

SUMMARY

The response of rheumatoid arthritis to a wide spectrum of therapeutic strategies attests to the complexity and heterogeneity of the disease and provides further impetus for studies that use these therapies to enhance our understanding of disease pathogenesis.

Rheumatoid arthritis

Therapeutic efficacy of depleting B cells or blocking T-cell costimulation in rheumatoid arthritis (RA) has confirmed the critical pathogenic role of adaptive immune responses. Yet, RA preferentially affects elderly individuals, in whom adaptive immunity to exogenous antigens begins to fail. Here, we propose that senescence of the immune system is a risk factor for RA, with chronic inflammation resulting from the accumulation of degenerate T cells that have a low threshold for activation and utilize a spectrum of novel receptors to respond to microenvironmental cues. The process of immunosenescence is accelerated in RA and precedes the onset of disease, the acceleration, in part, being conferred by the HLA-DR4 haplotype. Naive CD4(+) T cells in RA are contracted in diversity and restricted in clonal burst. Senescence of effector CD4(+) T cells is associated with the loss of CD28 and the de novo expression of KIR2DS2, NKG2D, and CX(3)CR1, all of which function as costimulatory molecules and reduce the threshold for T-cell activation. The synovial microenvironment promotes chronic persistent immune responses by facilitating ectopic lymphoid neogenesis, such as the formation of aberrant germinal centers. With the propensity to develop complex lymphoid architectures and to provide optimal activation conditions for senescent CD4(+) T cells, the synovium becomes a natural target for pathogenic immune responses in prematurely aged individuals.

Tolerability and safety of rituximab (MabThera)

Rituximab, a human/mouse chimeric anti-CD20 antibody, has become part of standard therapy for patients with CD20-expressing B-cell lymphoma, and is currently under investigation for other indications including autoimmune diseases, in particular rheumatoid arthritis (RA). Its characteristic tolerability profile was established soon after clinical testing began and compares favourably with chemotherapy. The majority of patients experience mild to moderate infusion-related reactions (IRRs) during the first administration of rituximab, but the incidence decreases markedly with subsequent infusions. Current data suggest that the type of adverse events in patients with RA are similar to those in lymphoma, but that adverse events related to the rituximab infusions are less severe and less frequent. Rituximab induces a rapid depletion of normal CD20-expressing B-cells in the peripheral blood, and levels remain low or undetectable for 2-6 months before returning to pretreatment levels, generally within 12 months. Serum immunoglobulin levels remain largely stable, although a reduction in IgM has been described. T-cells are unaffected by rituximab and consequently opportunistic infections rarely occur in association with rituximab therapy. When used in combination with a variety of chemotherapeutic regimens, rituximab does not add to the toxicity of chemotherapy, with the exception of a higher rate of neutropenia. However, this does not translate into a higher infection rate. Over 540,000 patients worldwide have now received rituximab and serious adverse reactions have occurred in a small minority of patients, but for the great majority of patients, rituximab is safe and well tolerated.

Anti-CD20 monoclonal antibody (rituximab) in the treatment of pemphigus

BACKGROUND

Pemphigus is a severe autoimmune blistering disorder caused by autoantibodies to desmoglein 1 and 3. The disease course is typically severe, thus requiring multiple immunosuppressive agents. The treatment is still challenging and in some patients with recalcitrant disease, therapies fail and therapeutic options are limited.

OBJECTIVES

To investigate whether depletion of B lymphocytes that are thought to produce disease-causing autoantibodies shows a long-term benefit in pemphigus.

METHODS

Five patients diagnosed as having pemphigus vulgaris and pemphigus foliaceus were treated with the monoclonal antibody rituximab. Rituximab was administered intravenously at a dosage of 375 mg m(-2) once weekly for 4 weeks.

RESULTS

The treatment was well tolerated and all patients showed a good response over a follow-up period of up to 3 years, allowing immunosuppressive treatment to be reduced or terminated. B-cell depletion persisted for 6-12 months, and in one patient for almost 3 years.

CONCLUSIONS

This study highlights the prolonged effect and disease control after one single course of rituximab and further extends the spectrum of treatments of bullous autoimmune disorders.

Impaired early B cell tolerance in patients with rheumatoid arthritis

Autoantibody production is a characteristic of most autoimmune diseases including rheumatoid arthritis (RA). The role of these autoantibodies in the pathogenesis of RA remains elusive, but they appear in the serum many years before the onset of clinical disease suggesting an early break in B cell tolerance. The stage of B cell development at which B cell tolerance is broken in RA remains unknown. We previously established in healthy donors that most polyreactive developing B cells are silenced in the bone marrow, and additional autoreactive B cells are removed in the periphery. B cell tolerance in untreated active RA patients was analyzed by testing the specificity of recombinant antibodies cloned from single B cells. We find that autoreactive B cells fail to be removed in all six RA patients and represent 35-52% of the mature naive B cell compartment compared with 20% in healthy donors. In some patients, RA B cells express an increased proportion of polyreactive antibodies that can recognize immunoglobulins and cyclic citrullinated peptides, suggesting early defects in central B cell tolerance. Thus, RA patients exhibit defective B cell tolerance checkpoints that may favor the development of autoimmunity.

Modulation of Dendritic Cell Maturation and Function by B Lymphocytes

Investigating the signals that regulate the function of dendritic cells (DC), the sentinels of the immune system, is critical to understanding the role of DC in the regulation of immune responses. Accumulating lines of evidence indicate that in addition to innate stimuli and T cell-derived signals, B lymphocytes exert a profound regulatory effect in vitro and in vivo on the Ag-presenting function of DC. The identification of B cells as a cellular source of cytokines, chemokines, and autoantibodies that are critically involved in the process of maturation, migration, and function of DC provides a rationale for immunotherapeutic intervention of autoimmune and inflammatory conditions by targeting B cells. Conversely, efficient cross-presentation of Ags by DC pulsed with immune complexes provides an alternative approach in the immunotherapy of cancer and infectious diseases.

Pathogenesis of rheumatoid arthritis: how early is early?

Studies of cytokine expression in rheumatoid arthritis have provided key insights into the pathogenesis of disease and have offered clues for effective therapy. Patterns of T-cell products in chronic rheumatoid synovitis suggest that T helper type 1 cells contribute to the perpetuation of disease. However, there is no guarantee that the mechanisms of late disease are identical to very early rheumatoid arthritis. Evaluation of the cytokine profile at the earliest time points after onset of symptoms could identify novel targets that prevent progression to chronic arthritis.

B cells as a therapeutic target in autoimmune diseases

Historically, the pathogenic role of B cells in autoimmune disease has been attributed to the formation of autoantibodies which, as soluble immunoglobulins or immunocomplexes, can trigger cellular damage and initiate the inflammatory cascade. Recent results from clinical trials applying B cell-directed therapeutics in rheumatoid arthritis and systemic lupus erythematosus have challenged such traditional views and encouraged novel ideas about the disease involvement of B cells. Suppression of disease activity, often disconnected from effects on autoantibody titers, has supported the notion that B cells may promote autoimmune disease by serving as antigen-presenting cells that sustain T cell activation. Likewise, B cells have been implicated in supporting the process of ectopic lymphoid neogenesis, a mechanism that stabilises pathogenic immune responses in target tissues and thus contributes to disease chronicity. As a general rule, clinical effects of B cell-directed therapeutics have often been unanticipated and unpredicted by experimental models, emphasis-ing the need to explore and verify disease principles in the patient.

Modeling human arthritic diseases in nonhuman primates

Models of rheumatoid arthritis (RA) in laboratory animals are important tools for research into pathogenic mechanisms and the development of effective, safe therapies. Rodent models (rats and mice) have provided important information about the pathogenic mechanisms. However, the evolutionary distance between rodents and humans hampers the translation of scientific principles into effective therapies. The impact of the genetic distance between the species is especially seen with treatments based on biological molecules, which are usually species-specific. The outbred nature and the closer anatomical, genetic, microbiological, physiological, and immunological similarity of nonhuman primates to humans may help to bridge the wide gap between inbred rodent strain models and the heterogeneous RA patient population. Here we review clinical, immunological and pathological aspects of the rhesus monkey model of collagen-induced arthritis, which has emerged as a reproducible model of human RA in nonhuman primates.

The Non-MHC Quantitative Trait Locus Cia5 Contains Three Major Arthritis Genes That Differentially Regulate Disease Severity, Pannus Formation, and Joint Damage in Collagen- and Pristane-Induced Arthritis

Cia5 is a locus on rat chromosome 10 which regulates the severity of collagen- and pristane-induced arthritis (CIA and PIA). To refine the region toward positional identification, Cia5 subcongenic strains were generated and studied in PIA and CIA. The protective effect of the telomeric locus Cia5a was confirmed in both models. A second arthritis severity locus (Cia5d) was identified within the most centromeric portion of Cia5. DA.F344(Cia5d) rats had a significantly lower median arthritis severity index in PIA, but not in CIA, compared with DA. On histologic analyses DA.F344(Cia5a) and DA.F344(Cia5d) congenics with PIA preserved a nearly normal joint architecture compared with DA, including significant reduction in synovial hyperplasia, pannus, angiogenesis, inflammatory infiltration, bone and cartilage erosions. Cia5 and Cia5a synovial levels of IL-1beta mRNA were reduced. Although both DA.F344(Cia5) and DA.F344(Cia5a) rats were protected in CIA, the arthritis scores of DA.F344(Cia5) were significantly higher than those of DA.F344(Cia5a), suggesting the existence of a third locus where F344-derived alleles centromeric from Cia5a contribute to increased arthritis severity. The existence of the third locus was further supported by higher levels of autoantibodies against rat type II collagen in DA.F344(Cia5) congenics compared with DA.F344(Cia5a). Our results determined that Cia5 contains three major arthritis severity regulatory loci regulating central events in the pathogenesis of arthritis, and differentially influencing CIA and PIA. These loci are syntenic to regions on human chromosomes 17q and 5q implicated in the susceptibility to rheumatoid arthritis, suggesting that the identification of these genes will be relevant to human disease.

CD20 Mimicry by a mAb Rituximab-Specific Linear Peptide: A Potential Tool for Active Immunotherapy of Autoimmune Diseases

An attractive, whether alternative or complementary, approach to passive immunotherapy (IT) with the anti-CD20 mAb rituximab for the treatment of autoimmune diseases is to stimulate the host to produce an anti-CD20 immune response by using peptides that mimic CD20 (mimotopes). The only mimotope reported to target CD20 antigen is a 43-mer polypeptide corresponding to the exposed domain of the molecule (from amino acid 142 to 184). Owing to its length, however, it failed to efficiently induce a CD20-specific response. A search has now been made for a smaller mimotope by biopanning a phage-display peptide library with rituximab. A total of 10 positive phage clones expressing six distinct sequences were isolated. Their alignment produced a motif that did not match any portion of the CD20 extracellular loop, whereas the motif bearing the 12-mer linear peptide Rp10-L specifically reacted with rituximab and inhibited its binding to CD20. Furthermore, in BALB/c mice Rp10-L-induced antibodies that reacted with the CD20(+) B lymphoid cell line Raji but not with the C20(-) T lymphoid cell line CEM. This peptide is currently being investigated to determine the effectiveness of CD20-based active IT for the treatment of autoimmune diseases.

Nine patients with anti-neutrophil cytoplasmic antibody-positive vasculitis successfully treated with rituximab

OBJECTIVES

Rituximab (RIT) is a monoclonal anti-CD20 antibody, which depletes B-lymphocytes but not plasma cells. RIT is used for treatment of B-cell lymphomas, but has also shown beneficial effects in autoimmune diseases. In this case series RIT was used in anti-neutrophil cytoplasmic antibody (ANCA)-positive vasculitis.

DESIGN

Case series with a structured follow-up of treated patients.

SETTING

Departments of Nephrology and Rheumatology of a university hospital.

SUBJECTS

Two women with myeloperoxidase-ANCA-positive microscopic polyangiitis and seven patients (five men and two women) with proteinase 3-ANCA-positive Wegener's granulomatosis. All patients were resistant to conventional therapy or had relapsed repeatedly after cessation of cyclophosphamide (Cyc).

INTERVENTIONS

The cases were treated with intravenous infusions of RIT once a week two times (three cases) or four times (six cases). To prevent formation of antibodies to RIT, mycophenolate mofetil (five patients), azathioprine (one patient), or a short course of Cyc (two patients) were added or allowed to continue.

MAIN OUTCOME MEASURES

Remission at 6 months assessed with Birmingham vasculitis activity score. The cases were followed 6-24 months and relapse rate was also noted.

RESULTS

Eight of nine patients responded completely and one case responded partially. Pulmonary X-ray improved (four cases), progress of lower extremity gangrene stopped (one case), remission of neuropathy was stable (one patient), renal vasculitis went into remission (two cases), and severe musculoskeletal pain improved (one case). Minor relapse in the nose occurred in two cases. No adverse events or major infections were noted.

CONCLUSION

RIT seems promising and safe in ANCA-positive vasculitis, and controlled studies should be conducted.

Stellenwert der neuen Biologicals und Zytokinantagonisten in der Therapie der juvenilen idiopathischen Arthritis (JIA)

Juvenile idiopathic arthritis is group of diseases of unknown aetiology characterised by the occurrence of chronic arthritis during childhood. Compared to adult onset rheumatoid arthritis, its course is more variable. Increasing knowledge of the inflammatory process as well as in molecular genetics and biotechnology has enable the production of new drugs, the biologicals. These are able to specifically block mechanisms of immune activation and thereby interfere with the inflammatory process. An increasing number of biologicals have been tried in clinical studies in adults suffering from rheumatoid arthritis, psoriasis or psoriasis arthritis and a couple of them were already licensed for treatment. Treatment of juvenile idiopathic arthritis by blockade of tumournecrosis-factor (TNF) using the soluble receptor Etanercept or the monoclonal antibodies Infliximab and Adalimumab showed comparable clinical efficacy. Blockade of TNF therefore already reached a certain place in the therapeutic algorythm for treatment of juvenile idiopathic arthritis. Currently, only Etanercept is licensed for treatment of active juvenile polyarthritis refractory to methotrexate. Studies using Infliximab and Adalimumab will be completed in the near future. However, antibodies blocking TNF may already be used in patients suffering from active uncontrolled chronic uveitis in whom visual impairment is threatening. TNF blockers may also be indicated in juvenile ankylosing spondylitis. The use of further biologicals, the interleukin-1 receptor antagonist Anakinra, Atlizumab (MRA) blocking the receptor for interleukin-6 or Abatacept, an inhibitory ligand of the co-stimulatory T cell membrane molecule CD28, remain experimental and should be preserved for clinical studies.

Current approaches to treatment of antibody-mediated rejection

Antibody-mediated rejection (AMR) has recently been recognized as a significant and unique form of rejection that is not amenable to treatment with standard immunosuppressive medications aimed at modification of T-cell function. Recent interest in AMR and the role of B cells in rejection has been aided by the concomitant discovery that C4d staining of renal biopsy tissue is strongly associated with AMR and a poor prognosis, and the emergence of desensitization protocols for treatment of highly human leukocyte antigen (HLA)-sensitized patients. Treatment options include: (i) the use of high-dose intravenous immunoglobulin (IVIG) which works by blocking anti-HLA antibody activity and through complement inhibition, (ii) the use of Rituxan (anti-CD20 chimeric antibody) to deplete B cells and interfere with antigen-presenting cell (APC) activity of B cells subsequently decreasing T-cell activation, and (iii) the use of plasmapheresis (PE) + anti-cytomegalovirus (CMV) immunoglobulin G (IgG) or IVIG in lower doses. This protocol removes deleterious anti-HLA antibodies and may also allow complexing of anti-HLA with anti-idiotypes in the anti-CMV IgG. Although early, data support the efficacy of all three approaches. Many centers are now designing protocols that utilize a combination of all three agents. In summary, recent advances in the diagnosis and treatment of AMR has allowed for significant improvements in outcomes of a condition usually associated with rapid graft failure. However, much work needs to be done to better understand the immunologic processes leading to AMR and how current therapies can be best used to effectively prevent and treat it.

Do We Need New Treatment That Goes beyond Tumor Necrosis Factor Blockers for Rheumatoid Arthritis?

Rheumatoid arthritis (RA) has a prevalence of approximately 1%, making it the most common inflammatory rheumatic disease. The outcome for RA patients has significantly improved during recent years. Factors include the introduction of new therapies such as tumor necrosis factor (TNF)-blocking agents and new treatment strategies, especially early and aggressive therapy, including combinations of several disease-modifying antirheumatic drugs (DMARDs). However, only 60-70% of RA patients respond to treatment with a TNF-blocking agent. In addition, most of these patients show only a partial response according to ACR20 criteria. Therefore, to ameliorate painful joint inflammation and prevent disability in RA patients, new treatment principles and more intelligent combination therapies are urgently needed. Interestingly, the strategy of switching patients who no longer respond to one of the TNF blockers to another has often turned out to be effective. Areas of ongoing research include combining TNF-blocking agents with DMARDs other than methotrexate. Also, several new biologics are being tested in clinical trials that promise to soon enhance the therapeutic armamentarium to fight RA. These biologics' mechanisms of action feature blockade of T cell costimulation by a CTLA4Ig fusion protein (abatacept); blockade of interleukin (IL)-6 signaling with an antibody to the IL-6 receptor (MRA); neutralizing IL-15 by a monoclonal antibody; and targeting B cells with an anti-CD20 antibody (rituximab). Other therapeutic approaches, such as blockade of chemokine receptors, adhesion molecules, complement components, and transcription factors regulating the inflammatory response, appear promising; however, they still need careful evaluation in placebo-controlled clinical studies.

Beneficial Effect of Rituximab in Combination with Oral Cyclophosphamide in Primary Chronic Cold Agglutinin Disease

Cold agglutinin disease (CAD) is an uncommon autoimmune hemolytic anemia characterized by B-cell proliferation. Conventional therapies for primary CAD such as corticosteroids, oral alkylating agents, splenectomy, interferon alpha, and plasma exchange are often ineffective at controlling the disease. The anti-CD20 monoclonal antibody rituximab (MabThera) depletes B-lymphocytes and thereby interferes with the production of cold agglutinin. We describe an elderly patient with primary (idiopathic) chronic CAD refractory to steroids who was successfully treated with 4 weekly infusions (375 mg/m2) of rituximab and 6 months of oral cyclophosphamide at a dosage of 60 mg/m2 per day. The increase in hemoglobin level and the decline in the plasma cold agglutinin titer were rapid (from the second rituximab infusion). The hematologic remission persisted for at least 8 months after treatment start, with no adverse effects. Rituximab and cyclophosphamide may be supplementary therapeutic modalities whose combination warrants further clinical investigation.

B cells in rheumatoid synovitis

In rheumatoid arthritis, T cells, B cells, macrophages, and dendritic cells invade the synovial membranes, establishing complex microstructures that promote inflammatory/tissue destructive lesions. B cell involvement has been considered to be limited to autoantibody production. However, recent studies suggest that B cells support rheumatoid disease through other mechanisms. A critical element of rheumatoid synovitis is the process of ectopic lymphoid neogenesis, with highly efficient lymphoid architectures established in a nonlymphoid tissue site. Rheumatoid synovitis recapitulates the pathways of lymph node formation, and B cells play a key role in this process. Furthermore, studies of rheumatoid lesions implanted in immunodeficient mice suggest that T cell activation in synovitis is B cell dependent, indicating the role played by B cells in presenting antigens and providing survival signals.

B cell targeted therapies

Although the precise pathogenesis of rheumatoid arthritis (RA) remains unclear, many cell populations, including monocytes, macrophages, endothelial cells, fibroblasts and B cells, participate in the inflammatory process. Ongoing research continues to evaluate the critical roles played by B cells in sustaining the chronic inflammatory process of RA. These findings have contributed to the development of targeted therapies that deplete B cells, such as rituximab, as well as inhibitors of B lymphocyte stimulation, such as belimumab. In a phase I trial, belimumab treatment significantly reduced CD20+ levels in patients with systemic lupus erythematosus. Phase I and phase II trials of rituximab found that rituximab plus methotrexate achieved significantly better American College of Rheumatology 50% responses for patients with RA than those patients receiving monotherapy with methotrexate. These clinical trial data present promising evidence for B cell targeted therapies as future therapeutic options for RA.

Unmet needs in rheumatoid arthritis

Until the pathophysiology/etiology of rheumatoid arthritis (RA) is better understood, treatment strategies must focus on disease management. Early diagnosis and treatment with disease-modifying antirheumatic drugs (DMARDs) are necessary to reduce early joint damage, functional loss, and mortality. Several clinical trials have now clearly shown that administering appropriate DMARDs early yields better therapeutic outcomes. However, RA is a heterogeneous disease in which responses to treatment vary considerably for any given patient. Thus, choosing which patients receive combination DMARDs, and which combinations, remains one of our major challenges in treating RA patients. In many well controlled clinical trials methotrexate and other DMARDs, including the tumor necrosis factor-α inhibitors, have shown considerable efficacy in controlling the inflammatory process, but many patients continue to have active disease. Optimizing clinical response requires the use of a full spectrum of clinical agents with different therapeutic targets. Newer therapies, such as rituximab, that specifically target B cells have emerged as viable treatment options for patients with RA.

[Applications of monoclonal antibodies and biotechnology products in the treatment of chronic inflammatory diseases]

In recent years we have noticed the arrival of biological drugs for the treatment of rheumatoid arthritis (RA), Crohn's disease (CD), psoriasis, and other chronic inflammatory diseases. Those drugs are produced with biotechnology methods and are defined as biologicals because of they work on the immune system. Different cellular groups and inflammation mediators participate in the inflammatory process, all of them susceptible of a therapeutic approach; they are so-called biological targets. Inhibition of TNF and interleukina 1 (IL-1) has proven effective for the control of inflammation in diseases as RA or CD. At present we have two types of inhibitors of TNF, specific monoclonal antibodies (infliximab, adalimumab) and cellular receptors (etanercept) and an IL-1 inhibitor (anakinra). The use of TNF inhibitors has given rise to a substantial change in the treatment of RA and CD because of its effectiveness. Together with this beneficial effect, an increase of infections (some of them severe) has occurred, especially tuberculosis. Other side effects that can be considered infrequent include demyelinization, heart failure, blood dyscrasias and lymphomas, which means that a thorough knowledge of these drugs is necessary for their use. Other potential biological drugs still in investigational phase are mentioned.

Targeting cellular adhesion molecules, chemokines and chemokine receptors in rheumatoid arthritis

The development of specific targeted therapies, such as anti-TNF-alpha treatment, for chronic inflammatory disorders such as rheumatoid arthritis, has significantly improved treatment, although not all patients respond. Targeting cellular adhesion molecules and chemokines/chemokine receptors as regulators of the extravasation and migration of leukocytes may provide a novel approach for the treatment of these diseases. Moreover, the possibility of developing small-molecule antagonists offers an excellent method for the oral delivery of compounds with a short half-life.

New therapies for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease, which continues to cause significant morbidity in affected persons. In the past few years, a number of new exciting therapeutic options have become available. These reflect the application of knowledge obtained from advancements in understanding of disease pathogenesis and underlying molecular mechanisms. A number of these therapies are outlined in the following review, including the various biological modifiers, in particular, anti-tumour necrosis factor-alpha agents and interleukin-1 (IL-1) receptor antagonists, which have been developed in recognition of the role of pro-inflammatory cytokines in RA. Also notable, is the current interest centring on the development and trials with B cell depletion therapies, specifically rituximab, in patients with RA. This demonstrates acknowledgment for a more significant role for B cells in the aetiology of RA, in contrast to the long held view that RA was a predominantly T cell mediated disease. To evaluate this therapeutic option for RA, salient features from recent rituximab trials have been collated. Finally, a selection of other therapeutic alternatives, including anti-IL-6 receptor monoclonal antibody and tacrolimus, and newer anti-rheumatic therapies presently in development are summarized.

New therapies for systemic lupus erythematosus

In the past 40 years, prognosis for patients with systemic lupus erythematosus (SLE) has improved, with 10-year survival now approximately 90%. This is due probably to a combination of earlier disease diagnosis and diagnosis of milder disease, due in part to availability of multiple serological tests for SLE, use of steroids and other immunosuppressive agents, and availability of renal dialysis and transplantation. Despite this, however, the potential for significant morbidity and mortality remains in the group of patients with partially responsive or treatment resistant disease. More recently, advancements in the understanding of molecular mechanisms involved in the pathogenesis of SLE have translated to the development of novel therapies, offering possible alternatives to this patient cohort. Discussion of these pharmacological options and ongoing research forms the basis of this review.

Combination therapy in multiple sclerosis

Over the past decade, multiple sclerosis (MS) has become a treatable neurologic illness. However, given the rather modest benefit of the currently available disease-modifying agents, as well as the challenges associated with performing placebo-controlled, equivalence, and superiority trials, the logic of combining therapies in MS has considerable appeal. Selecting agents for combination requires careful consideration, as the immunomodulating activity of one drug could potentially interfere with the therapeutic effect of another, and certain combinations may be associated with unforeseen adverse effects. Rigorously controlled studies are needed to determine the safest and most effective use of new and existing MS therapies.

Rheumatoid arthritis: non-tumor necrosis factor targets

PURPOSE OF REVIEW

The treatment of rheumatoid arthritis has been revolutionised in recent years with the advent of biologic treatments. The purpose of this review is to outline new treatments that target the inflammatory pathway in rheumatoid arthritis other than tumor necrosis factor-alpha.

RECENT FINDINGS

As the use of anti-tumor necrosis factor-alpha treatment has become more widespread, the number of patients in whom this treatment is unsuccessful has also accumulated. Contraindications such as infection and cardiac failure further add to the number of patients who need alternative treatment. A better understanding of the inflammatory pathway in rheumatoid arthritis has led to interest in other therapeutic targets. Promising treatments such as interleukin-6 antagonists (MRA), CTLA4Ig (abatacept), and anti-B cell therapy (rituximab) have already been tested in randomized controlled trials over the past year. Other cytokines have been identified and have been shown to be of benefit in animal models, including interleukin-15, interleukin-17, and interleukin-18, and clinical trials of these agents are currently under way.

SUMMARY

For patients with rheumatoid arthritis that does not respond to anti-tumor necrosis factor-alpha treatment, the promising alternatives MRA, abatacept, and rituximab have been tested. It is hoped that these agents will become available shortly.

Antigen-specific B cells are required as APCs and autoantibody-producing cells for induction of severe autoimmune arthritis

B cells play an important role in rheumatoid arthritis, but whether they are required as autoantibody-producing cells as well as APCs has not been determined. We assessed B cell autoantibody and APC functions in a murine model of autoimmune arthritis, proteoglycan (PG)-induced arthritis, using both B cell-deficient mice and Ig-deficient mice (mIgM) mice that express an H chain transgene encoding for membrane-bound, but not secreted, IgM. The IgH transgene, when paired with endogenous lambda L chain, recognizes the hapten 4-hydroxy-3-nitro-phenyl acetyl and is expressed on 1-4% of B cells. B cell-deficient and mIgM mice do not develop arthritis after immunization with PG. In adoptive transfer of PG-induced arthritis into SCID mice, T cells from mIgM mice immunized with PG were unable to transfer disease even when B cells from PG-immunized wild-type mice were provided, suggesting that the T cells were not adequately primed and that Ag-specific B cells may be required. In fact, when PG was directly targeted to the B cell Ig receptor through a conjugate of 4-hydroxy-3-nitrophenyl acetyl-PG, T cells in mIgM mice were activated and competent to transfer arthritis. Such T cells caused mild arthritis in the absence of autoantibody, demonstrating a direct pathogenic role for T cells activated by Ag-specific B cells. Transfer of arthritic serum alone induced only mild and transient arthritis. However, both autoreactive T cells and autoantibody are required to cause severe arthritis, indicating that both B cell-mediated effector pathways contribute synergistically to autoimmune disease.

AntiArthritis Therapies 2005

This meeting, hosted by Visiongain and B2B conferences, comprised approximately 35 delegates, predominantly from the pharmaceutical industry, and promoted interactive discussion. It covered a broad range of drug discovery and development activities, ranging from preclinical studies with compounds requiring further optimisation, through to launched drugs used in the treatment of arthritis today.

Fc receptor targeting in the treatment of allergy, autoimmune diseases and cancer

Immune activation and inhibitory receptors play an important role in the maintenance of an adequate activation threshold of various cells in our immune system. Analyses of murine models show that the inhibitory Fcreceptor, FcgammaRIIB plays an indispensable role in the suppression of anti-body-mediated allergy and autoimmunity. In contrast, the activating-type Fcreceptors (FcRs) are essential for the development of these diseases, suggesting that regulation of inhibitory or activating FcR is an ideal target as a therapeutic agent. In addition, recent crystal structural analyses of FcR-Ig-Fc fragment complexes provide an effective approach for developing FcR-targeting drugs. This review summarises recent advances of FcR, which were mainly obtained by murine studies, and highlights novel antibodies as possible FcR-targeting therapies for allergy, autoimmune diseases and cancer.

A functional variant in FCRL3, encoding Fc receptor-like 3, is associated with rheumatoid arthritis and several autoimmunities

Rheumatoid arthritis is a common autoimmune disease with a complex genetic etiology. Here we identify a SNP in the promoter region of FCRL3, a member of the Fc receptor-like family, that is associated with susceptibility to rheumatoid arthritis (odds ratio = 2.15, P = 0.00000085). This polymorphism alters the binding affinity of nuclear factor-kappaB and regulates FCRL3 expression. We observed high FCRL3 expression on B cells and augmented autoantibody production in individuals with the disease-susceptible genotype. We also found associations between the SNP and susceptibility to autoimmune thyroid disease and systemic lupus erythematosus. FCRL3 may therefore have a pivotal role in autoimmunity.

Inflammation in juvenile idiopathic arthritis

Inflammation evolved to aid in the clearance of microorganisms. In pediatric arthritides, the inflammation persists and causes damage to the joint. The contribution of the innate immune system to inflammation is significant and can be exploited therapeutically. Although cells of the adaptive immune system such as T cells and B cells participate in the disease process, many of the features of arthritis are directly attributable to inflammatory mediators. Recent advances in the understanding of these processes have led to dramatic improvements in treatment.

MAINTENANCE OF SERUM ANTIBODY LEVELS

In vertebrates, serum antibodies are an essential component of innate and adaptive immunity and immunological memory. They also can contribute significantly to immunopathology. Their composition is the result of tightly regulated differentiation of B lymphocytes into antibody-secreting plasma blasts and plasma cells. The survival of antibody-secreting cells determines their contribution to the immune response in which they were generated and to long-lasting immunity, as provided by stable serum antibody levels. Short-lived plasma blasts and/or plasma cells secrete antibodies for a reactive immune response. Short-lived plasma blasts can become long-lived plasma cells, probably by competition with preexisting plasma cells for occupation of a limited number of survival niches in the body, in a process not yet fully understood. Limitation of the number of long-lived plasma cells allows the immune system to maintain a stable humoral immunological memory over long periods, to react to new pathogenic challenges, and to adapt the humoral memory in response to these antigens.

Biomarkers of endothelial dysfunction, cardiovascular risk factors and atherosclerosis in rheumatoid arthritis

Cardiovascular event rates are markedly increased in rheumatoid arthritis (RA), and RA atherogenesis remains poorly understood. The relative contributions of traditional and nontraditional risk factors to cardiovascular disease in RA await elucidation. The present study comprises three components. First, we compared biomarkers of endothelial dysfunction (vascular cell adhesion molecule [VCAM]-1, intercellular adhesion molecule [ICAM]-1 and endothelial leucocyte adhesion molecule [ELAM]-1) in 74 RA patients and 80 healthy control individuals before and after controlling for traditional and nontraditional cardiovascular risk factors, including high-sensitivity C-reactive protein (hs-CRP), IL-1, IL-6 and tumor necrosis factor-α. Second, we investigated the potential role of an extensive range of patient characteristics in endothelial dysfunction in the 74 RA patients. Finally, we assessed associations between biomarkers of endothelial dysfunction and ultrasonographically determined common carotid artery intima–media thickness and plaque in RA. The three biomarkers of endothelial dysfunction, as well as hs-CRP, IL-1, IL-6 and tumor necrosis factor-α, were higher in patients than in control individuals (P < 0.0001). Patients were also older, exercised less and had a greater waist circumference, blood pressure and triglyceride levels (P ≤ 0.04). Five patients had diabetes. Differences in endothelial function were no longer significant between patients and controls (P = 0.08) only after both traditional and nontraditional cardiovascular risk factors were controlled for. In the 74 RA patients, IL-6 predicted levels of all three biomarkers (P ≤ 0.03), and rheumatoid factor titres and low glomerular filtration rate (GFR) both predicted levels of VCAM-1 and ICAM-1, independent of traditional cardiovascular risk factors (P ≤ 0.02). VCAM-1 was associated with common carotid artery intima–media thickness (P = 0.02) and plaque (P = 0.04) in RA. Patients had impaired endothelial function, less favourable traditional cardiovascular risk factor profiles, and higher circulating concentrations of hs-CRP and cytokines compared with healthy control individuals. Both traditional and nontraditional cardiovascular risk factors contributed to the differences in endothelial function between RA patients and healthy control individuals. IL-6, rheumatoid factor titres and low GFR were independently predictive of endothelial dysfunction in RA. Disease-modifying agents that effectively suppress both cytokine and rheumatoid factor production, and interventions aimed at preserving renal function may attenuate cardiovascular risk in RA.

Modulating co-stimulation: a rational strategy in the treatment of rheumatoid arthritis?

Rheumatoid arthritis (RA) is a common destructive inflammatory disease that affects 0.5-1% of the population in many countries. Even though several new treatments have been introduced for patients with RA, a considerable proportion of patients do not benefit from these, and the need for alternative treatment strategies is clear. This review explores the potential for a therapy targeting the adaptive immune system by modulating co-stimulation of T cells with a CTLA4-Ig fusion protein (abatacept).

A HEV-restricted sulfotransferase is expressed in rheumatoid arthritis synovium and is induced by lymphotoxin-alpha/beta and TNF-alpha in cultured endothelial cells

BACKGROUND

The recruitment of lymphocytes to secondary lymphoid organs relies on interactions of circulating cells with high endothelial venules (HEV). HEV are exclusive to these organs under physiological conditions, but they can develop in chronically-inflamed tissues. The interaction of L-selectin on lymphocytes with sulfated glycoprotein ligands on HEV results in lymphocyte rolling, which represents the initial step in lymphocyte homing. HEV expression of GlcNAc6ST-2 (also known as HEC-GlcNAc6ST, GST-3, LSST or CHST4), an HEV-restricted sulfotransferase, is essential for the elaboration of L-selectin functional ligands as well as a critical epitope recognized by MECA-79 mAb.

RESULTS

We examined the expression of GlcNAc6ST-2 in relationship to the MECA-79 epitope in rheumatoid arthritis (RA) synovial vessels. Expression of GlcNAc6ST-2 was specific to RA synovial tissues as compared to osteoarthritis synovial tissues and localized to endothelial cells of HEV-like vessels and small flat-walled vessels. Double MECA-79 and GlcNAc6ST-2 staining showed colocalization of the MECA-79 epitope and GlcNAc6ST-2. We further found that both TNF-alpha and lymphotoxin-alphabeta induced GlcNAc6ST-2 mRNA and protein in cultured human umbilical vein endothelial cells.

CONCLUSION

These observations demonstrate that GlcNAc6ST-2 is induced in RA vessels and provide potential cytokine pathways for its induction. GlcNAc6ST-2 is a novel marker of activated vessels within RA ectopic lymphoid aggregates. This enzyme represents a potential therapeutic target for RA.

Management of therapy-resistant systemic lupus erythematosus with rituximab: report of a case and review of the literature

Therapy of systemic lupus erythematosus (SLE) with major organ involvement consists of aggressive immunosuppression with glucocorticoids and cytotoxic agents. When remission is achieved, maintenance therapy is begun to reduce the risk of relapse while minimizing toxicity. Remission with standard therapy is, however, not always achieved. We discribe a women with SLE and microangiopathic haemolytic anaemia and thrombocytopenia, pneumonitis and nephritis refractory to high-dose steroids, pulse cyclophosphamide, plasmapheresis and intravenous immunoglobulins. The anti-CD20 monoclonal antibody rituximab was administered, resulting in major clinical and biochemical improvement. Therapy-resistant SLE generally has an ominous prognosis. A few anecdotal reports and small open studies describe beneficial effects of rituximab in these cases. Rituximab may be a promising new approach to improve the dismal outcome of therapy-resistant SLE.