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Autoimmune response is diverse. This diversity is thought not to take place at the beginning of the autoimmune process but to occur as the disease evolves. It is mainly the consequence of the so-called epitope-spreading phenomenon and of the cross-reactivity of antibodies. Analysing autoantibody repertoire constitutes a powerful means to understand physiopathological processes at work in various diseases, mainly autoimmune diseases. In particular this analysis opens the way to precisely identify autoantigens and their changes in various pathological situations, and allows providing new biological markers in chronic inflammatory diseases. New methodologies have recently emerged for the analysis of the autoantibody repertoire in a given individual. They propose diagnostic approaches no more related upon few markers but founded upon analysis of global changes of the antibody repertoire. They belong to methodologies called target-oriented proteomics. Their common feature is to isolate autoantigens by means of affinity chromatography based upon antibody/antigen reactions. Autoantibodies to be studied interact with a protein substratum susceptible to include autoantibody targets. These interactions take place on solid macro- or microsurfaces, i.e. membrane filters or chips. Several strategies can be used for locating the specific autoantibody/autoantigen complexes and for identifying behind autoantigens. In this paper three approaches, namely, the recombinant protein chips, the SELDI techniques and the 2-D gel electrophoresis linked to mass spectrometry are described and compared.

Tumour necrosis factor (TNF)-alpha plays a key role in the pathogenesis of rheumatoid arthritis (RA). It binds to two receptors, namely TNF receptor (TNFR)I and TNFRII. Several studies have suggested an association between TNFRII 196R/R genotype and RA. The objective of the present study was to evaluate the predictive value of the TNFRII 196R allele for RA diagnosis and prognosis in a cohort of patients with very early arthritis. We followed up a total of 278 patients recruited from the community, who had swelling of at least two joints that had persisted for longer than 4 weeks but had been evolving for less than 6 months, and who had not received disease-modifying antirheumatic drugs or steroid therapy. At 2 years, patients were classified according to the American College of Rheumatology criteria. All patients were genotyped with respect to TNFRII 196M/R polymorphism. Radiographs of hands and feet (read according to the modified Sharp method) and the Health Assessment Questionnaire were used to quantify structural and functional severity. The cohort of 278 patients was found to include 156 and 122 RA and non-RA patients, respectively. The TNFRII 196R allele was found to be associated with RA (P = 0.002). However, progression of radiographic severity and Health Assessment Questionnaire scores over 1 year did not differ between carriers of the 196R allele and noncarriers. Our findings suggest that the TNFRII 196R allele may be associated with RA diagnosis but that it does not predict early radiographic progression or functional severity in patients with very early, unclassified arthritis.

Objectives: Prescribing foot orthotics in rheumatoid arthritis patients with symptomatic forefoot involvement is a standard practice. However, limited research has been reported regarding gait and pain improvement with the use of foot orthotics., Patients and Methods: Sixteen patients (13 F, 3 M; mean age: 52 +/- 12 years) with metatarsalgia due to rheumatoid arthritis were included in this prospective, randomized with crossover study, and received foot orthotics. At 1 month follow-up, space and time gait variables with and without foot orthotics were assessed by Bessou's locometer; pain was assessed by visual analogue scale (VAS)., Results: Pain levels significantly decreased (P = 0.008) by wearing foot orthotics. Despite a significant step length increase (P = 0.05) with orthotics, there was no significant improvement of stride length, cadence, or walking speed which was the main assessment criterion., Conclusions: Wearing foot orthotics improves pain, but not sufficiently to improve gait in rheumatoid arthritis patients with metatarsalgia. Foot orthotics improved comfort levels because of a decrease in pain, but was not sufficient to correct gait.

Large-scale analysis of gene expression with cDNA arrays is spreading over many biological fields, including rheumatology. In this report, we wish to explain the principle and main advantages of this tool in the context of our discipline. Until 1995, analysis of gene expression was conducted for a few genes at a time but DNA chips now allow one to monitor the expression of thousands of genes in a single experiment and analyze the transcriptome, i.e. the whole of the transcripts in a given cell or tissue. Whatever the platform used (macro- or microarrays, oligo-chips), this technology rests upon the hybridization of i) a set of cDNA clones tethered to a solid support (nylon or glass) as probes, and ii) labelled cDNAs that are reverse-transcribed from bulk mRNAs extracted from a cell or tissue sample as a target. The end result is information on the relative abundance of every mRNA between two or more samples. The transcriptome analysis has two main objectives in rheumatology: i) identifying a gene expression profile that is a hallmark of a pathology and using it for a diagnostic or prognostic purpose, and ii) gathering genes with similar changes of expression, which allows one to specify the identity of novel proteins involved in a well-known intracellular cascade of regulation or even to identify new cascades.

In a man with osteoarthritis of the knee, Actinomyces naeslundii septic arthritis developed after intra-articular injection of hyaluronate. Actinomyces is an anaerobic Gram-positive rod. The outcome was favorable after treatment with two antibiotics and arthroscopy. The nature of the organism and its location to a joint are unusual features of this case, which illustrates the need to search for a septic complication before accepting a diagnosis of inflammation related to hyaluronate injection.

To identify new autoantibody populations in patients with rheumatic diseases, a cDNA expression library was immunoscreened with a rheumatoid arthritis (RA) patient's serum which contains autoantibodies binding to uncharacterized polypeptides by Western-blotting. One clone encoding the amino-terminal region (Nt) [domain L and half of domain I] of human calpastatin was selected. Different fragments of the selected cDNA were prepared and the corresponding recombinant polypeptides were produced by in vitro translation and analysed by Western blotting. Most RA sera bound to recombinant amino-terminal region and domain I but not to domain L. This prompted us to use a recombinant polypeptide corresponding to the domain I of calpastatin as the antigen in a solid-phase ELISA to test sera from patients with various systemic rheumatic diseases and healthy controls.Anti-calpastatin domain I antibodies (ACAST-DI Ab), were detected by ELISA in RA, systemic lupus erythematosus (SLE), Sjögren's syndrome and control sera at respective frequencies of 10, 9, 0 and 1%. These Ab did not have prognostic value in early RA; high levels were significantly associated with vasculitis in SLE. Antibodies reacting with the calpastatin amino-terminal region are produced during systemic rheumatic diseases and are predominantly directed against domain I. High levels of these Ab may constitute a marker of vasculitis in SLE.

Objective: To identify a new autoantigen/autoantibody population in rheumatoid arthritis (RA) sera., Methods: Following a population-based recruitment effort, 255 patients with very early arthritis (median disease duration 4 months) were studied using different clinical, biologic, and radiologic assessments. After a followup period of 1 year, patients were classified as having RA (n = 145), non-RA rheumatic diseases (n = 70), and undifferentiated arthritis (n = 40). Patients' sera were analyzed by one-dimensional (1D) and 2D Western blotting. The recognized 50-kd protein was analyzed by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS). RA serum reactivities were evaluated against the recombinant protein synthesized by an in vitro coupled transcription-translation system., Results: On 1D Western blots, 36 of the 145 RA sera bound to a 50-kd polypeptide. On 2D Western blots, anti-50-kd+ RA sera recognized a triplet of isoelectric point 6.5-7.0 and a molecular mass of 50 kd. The 3 spots of the triplet were analyzed by MALDI-TOF MS and were shown to correspond to human alpha-enolase. A goat anti-enolase antiserum, which recognized a band comigrating with the 50-kd antigen on 1D Western blots, gave a labeling pattern on 2D Western blots similar to that observed with anti-50-kd+ RA sera. Among the 36 RA sera that identified alpha-enolase in protein maps, only 8 recognized the recombinant (unmodified) alpha-enolase. The specificity of anti-alpha -enolase antibodies for RA was 97.1%. Half of the anti-alpha -enolase-positive RA patients were negative for both rheumatoid factor and antifilaggrin antibodies. The presence of anti-alpha-enolase antibodies was the greatest predictive factor of radiologic progression in the first 66 RA patients included., Conclusion: Autoantibodies to alpha-enolase, an enzyme of the glycolytic pathway, are present in the sera of patients with very early RA and have potential diagnostic and prognostic value for RA.

Synovial diseases of the hip are often overlooked because they are far less frequent that osteoarthritis and because this joint is deep and so difficult to examine. The more important cause is septic arthritis; it requires an hospitalization in emergency. Synovial tissue may also be at the beginning of the spondylarthropathy or, more rarely, of rheumatoid arthritis. In acute forms, diagnosis must be done before any radiological destructive changes. Aspiration of the hip and synovial biopsy are necessary for the diagnosis. In subacute or chronic forms, computed tomography and/or magnetic resonance imaging are useful tools to suspect the diagnosis and to guide a biopsy.

Many physicians are unfamiliar with the characteristics of the sternocostoclavicular joint (SCCJ). Disorders of the SCCJ, although common, frequently escape recognition. Computed tomography (CT) with thin slices and no gap is at presentthe best means of investigating the SCCJ. CTfeatures in normal subjects have been described in detail; some are misleading. The most common SCCJ disorder is degenerative disease manifesting as osteoarthritis or as periarticular lesions causing antero-medial dislocation of the clavicle. Septic arthritis is the most severe disorder and can lead to mediastinitis. All inflammatory joint diseases, including spondyloarthropathies, can affect the SCCJ. SCCJ involvement is a typical component of the osteoarticular manifestations seen in patients with palmoplantar pustulosis.