Proteomics is a fast-growing discipline in biomedicine that can be defined as the large-scale characterization of the entire protein complement of a cell, tissue or organism. Because protein levels and function may be critically dependent upon post-transcriptional mechanisms (e.g. post-translational modifications), there has been significant interest in directly examining protein structure and function. It is now clear that proteomics studies may unmask previously unknown functions of proteins or protein interactions. However, proteomics in the field of rheumatology is still in its infancy. This review guides the reader through the consecutive steps of a proteomics study and provides an outline of the applications in the field of rheumatology, which may range from proteome analyses of biological fluids of rheumatic diseases to identify possible new diagnostic tools, towards more pathophysiological studies on target tissues, such as synovial tissue or articular cartilage. Proteomics has great potential in the field of rheumatology and will no doubt have a great impact on our molecular understanding of these complex diseases.

Systemic sclerosis, scleroderma (SSc) is a disabling condition that shortens life expectancy. Disease heterogeneity and difficulties separating SSc from SSc-like conditions make classification an important issue. Limited cutaneous and diffuse cutaneous SSc, with different severity and survival, have been recognized for several years as distinct subsets. Some authors have suggested an intermediate cutaneous form with intermediate survival. This issue remains unsettled, however. The technique of capillaroscopy is helpful as an adjunct diagnostic tool to separate idiopathic Raynaud's phenomenon from SSc. Digitized video-capillaroscopy is developing as a powerful new method to assess individual capillaries over time. Using the simpler techniques of video-capillaroscopy, different patterns have been described and named 'early', 'active', 'late' and 'slow'. The value of nailfold video-capillaroscopy to distinguish different subsets or provide prognostic information for use in daily practice remains to be assessed. The features of CREST (calcinosis, Raynaud's, oesophagus dysmotility, sclerodactyly, telangiectasias) are not confined to single subsets of SSc. There is no convincing evidence of any advantage for distinguishing the limited, intermediate and diffuse forms of SSc rather than only the limited and diffuse forms.

The mechanism by which COX inhibitors exert their analgesic effect is well established. However, data show no direct correlation between drug concentrations in plasma and the analgesic or adverse effects in chronic inflammatory conditions. This represents a major problem in the development of COX inhibitors, since it is difficult to predict the appropriate dosing regimen for the treatment of chronic inflammatory pain, based upon information from pre-clinical studies and eventually early clinical studies. The factors that determine response in inflammatory pain must be understood in order to make predictions about the time course of the analgesic effect. In this review the determinants of drug response and their variability will be discussed: physicochemical properties, pharmacokinetics (PK), pathophysiology and disease progression. From a mechanistic point of view, endogenous mediators of inflammation might be used as a biomarker for the analgesic effect and safety assessment. Such a biomarker can be an intermediate step between drug exposure and response. In addition, its concentration-effect relationship could be characterized by pharmacokinetic-pharmacodynamic (PK/PD) modelling. Indeed, recent investigations have shown that COX-2 inhibition, as determined by modelling of prostaglandin E2 (PGE2) levels in the whole blood assay in vitro can be used as a marker to predict drug effects (analgesia) in humans. A model-derived parameter, IC80, (total and unbound) was found to correlate directly with the analgesic plasma concentration of different COX inhibitors varying in enzyme selectivity. These findings indicate that PGE2 and thromboxane B2 inhibition can be used to predict and select efficacious doses in humans.

Rituximab (MabThera/Rituxan) is a therapeutic monoclonal antibody against CD20, an antigen expressed by B cells but not B-cell progenitor or plasma cells. It is currently approved for the treatment of relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL) and is well tolerated and efficacious. A small open-label study (conducted by Edwards and Cambridge) indicated that selective depletion of B cells using rituximab led to sustained benefits for patients with active rheumatoid arthritis. A 24-week, double-blind, randomized controlled trial was carried out to confirm these initial observations. In total, 161 patients with active rheumatoid arthritis were randomized to one of four treatment groups: rituximab monotherapy; rituximab plus methotrexate (R+MTX); rituximab plus cyclophosphamide (R+CTX); or methotrexate alone (MTX). Rituximab was administered as two 1000 mg infusions on days 1 and 15. An analysis at 24 weeks showed that the proportion of patients achieving an ACR20 response was significantly greater (P < or = 0.025 for all three comparisons) in all the rituximab groups compared with the MTX control group (rituximab alone, 65%; R+CTX, 76%; R+MTX, 73%; MTX alone, 38%). Both ACR50 (43 vs 13%; P = 0.005) and ACR70 (23 vs 5%; P = 0.048) responses were also significantly higher for the R+MTX group compared with the MTX group. The rituximab groups showed no significant safety differences compared with the MTX arm. The majority of adverse events were of mild to moderate intensity. Rituximab is a novel targeted therapy for the treatment of rheumatoid arthritis and it appears to be highly effective, safe and well tolerated.

The role of T cells in the pathogenesis of RA is well established, whereas to date the precise contribution of B cells is less well defined. B cells have many potential key roles: they can act as antigen-presenting cells, secrete pro-inflammatory cytokines (including tumour necrosis factor-alpha), produce rheumatoid factor (RF) and other autoantibodies and activate T cells. B cells act as antigen-presenting cells by processing and presenting antigenic peptides to T cells, which become activated, proliferate and exert pro-inflammatory activities. RF may also play a role in perpetuating B-cell activation and antigen presentation to T cells, thus leading to sustained production of RF. This, combined with RF immune-complex-mediated complement activation, may contribute to the sustained inflammatory response. Studies have shown that the use of an anti-CD20 monoclonal antibody in RA depletes circulating B cells, resulting in improvement in disease activity for up to 1 yr. It is thus evident that B cells play a central role in the pathophysiology of RA and therefore merit further investigation as a therapeutic target.

Selective B-cell depletion with anti-CD20 therapy is a promising novel treatment option for patients with refractory autoimmune disease. The anti-CD20 antibody, rituximab, is the first therapeutic monoclonal antibody to have been approved by the European Medical Agency (EMEA) and the US Food and Drug Administration (FDA) for the treatment of relapsed, low-grade, follicular non-Hodgkin's lymphoma. Rituximab is now being studied in a range of autoimmune diseases, most notably rheumatoid arthritis, but also chronic immune thrombocytopenic purpura and systemic lupus erythematosus. Current data obtained from studies of rituximab single-agent therapy for autoimmune disease show good tolerability and sustained improvement in disease symptoms, although the precise mechanisms of action in autoimmunity remain to be fully clarified. Future research is likely to be focused on the optimization of responses with rituximab-based therapy. However, early observations suggest that this approach is likely to yield significant clinical benefits in a wide range of organ-specific and systemic autoimmune diseases.

Antiphospholipid syndrome (APS) is one of the most frequent acquired thrombophilias. Thromboses can be at both the venous and arterial level, are usually recurrent and frequently affect cerebral circulation. Although it is difficult to predict which patients with antiphospholipid antibodies (aPL) will develop thrombosis, once a thrombotic event has taken place, secondary prevention is mandatory. Recommendations for treatment of APS have long been based on studies with a retrospective design. Recently, three prospective studies (two controlled and one uncontrolled small series) have addressed the role of antiaggregant and anticoagulant therapy in patients with stroke and aPL. However, results from prospective and retrospective studies are not in full agreement. In addition to the obvious differences in design, other factors such as the important variability in the study groups account for the discrepancy. While future investigation must better define homogeneous subsets of patients with APS, current secondary prophylaxis of thrombosis in these patients must be tailored according to individual estimated risk of recurrences, risk of haemorrhage and severity of potential recurrent events. Due to the often devastating consequences of stroke, we believe there is a place for prolonged, high-intensity anticoagulation in patients with APS and cerebral arterial thrombosis.

To determine the outcome, following the onset of juvenile idiopathic inflammatory arthritis, in terms of remission of disease activity, loss of function and structural damage based on a review of the available published data.

To assess the relative contributions of demographic, clinical and laboratory variables in predicting outcome in juvenile idiopathic inflammatory arthritis (JIA), based on a review of the existing literature.

The role of surgery in the clinical management of patients with rheumatoid arthritis (RA)-associated hand dysfunction is still a subject of controversy. The efficacy of surgery in RA-associated hand dysfunction is assessed through an exhaustive review of published studies.

The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

Newer TNF blockers (etanercept, infliximab and adalimumab) have contributed greatly to the control of chronic inflammatory disease. Many of the damaging inflammatory mechanisms that they inhibit are, however, important in maintaining tuberculosis in the latent phase (latent tuberculosis infection or LTBI). There is considerable evidence that links reactivation of LTBI to the use of anti-TNF monoclonal antibody (mAb) treatments, which appear to result in disruption of the granuloma that normally compartmentalizes but does not kill Mycobacterium tuberculosis during LTBI. This effect can be explained, in part, by directly neutralizing TNF, which plays a key role in tuberculosis immunity. To the clinician, dealing with LTBI in patients on these medications is an important issue. Prescribers should seek local expert help in this regard, as global LTBI treatment regimens differ. Nonetheless, screening for and treating LTBI will prevent reactivation in most patients. LTBI screening should include a careful history, tuberculin skin test and chest radiograph. Prophylactic treatment (e.g. isoniazid for 9 months) should be offered to patients with LTBI, in accordance with local advice. False-negative tuberculin skin test results can be expected in these patient groups. False-negative skin tests also mean that clinicians cannot be complacent about patients on TNF blockers who lack evidence of LTBI. On the contrary, because tuberculosis disease can be lethal, all treated patients should be advised to seek medical attention if symptoms suggestive of tuberculosis emerge. The indications for these successful agents are expanding, and efficient management of the LTBI issue should improve their safety profile.

Rheumatoid arthritis (RA) is characterized by variable degrees of joint inflammation, joint destruction, progressive disability and premature death. Destruction of joint cartilage and bone may occur early during disease, as was shown in longitudinal studies of RA, and there is increasing consent among rheumatologists that early diagnosis and early initiation of therapy with disease-modifying anti-rheumatic drugs (DMARDs) can limit the severity of RA. Unfortunately, the currently used diagnostic and predictive indicators (clinical, laboratory and radiological) are of limited value for making an early diagnosis and prognosis of the disease course at the individual level, thus reducing optimal benefit from present and emerging therapies. Therefore, this review focuses on the multidisciplinary aspects of neuroendocrine-immune changes in RA.

Rheumatoid arthritis (RA) is a symmetrical polyarticular disease of unknown aetiology that affects primarily the diarthrodial joints. Characteristic features of RA pathogenesis are synovial hyperplasia and inflammation accompanied by cartilage loss and joint destruction. Synovial hyperplasia and inflammation are a consequence of an increase in the macrophage-like and fibroblast-like synoviocytes of the synovial intimal lining associated with infiltration of leucocytes into the subintimal space. Although therapeutic interventions are available, the disease persists despite therapy in a significant fraction of patients. Several lines of evidence have substantiated a crucial role of activated fibroblast-like synoviocytes (FLS) during RA pathogenesis. The hyperplastic FLS population potentially promotes leucocyte infiltration and retention. The rheumatoid synovium eventually transforms into a pannus that destroys articular cartilage and bone. There are no approved drugs that are known to target the FLS in RA, and the underlying mechanisms driving FLS activation remain unresolved. In this review, the importance of Wnt-frizzled (Fz)-mediated signalling in the autonomous activation of FLS is discussed. Anti-Wnt/anti-Fz antibodies, Fz receptor antagonists or small-molecule inhibitors of Wnt-Fz signalling might be useful for therapeutic interventions in refractory RA.