Cytokines are believed to play an important role in the pathogenesis of systemic lupus erythematosus (SLE). However, for tumour necrosis factor alpha (TNF-alpha) both beneficial and deleterious effects have been reported. To obtain information about the involvement of this cytokine in the pathophysiology of SLE, serum levels of TNF-alpha, the soluble forms of the 55 and 75 kDa tumour necrosis factor receptors (TNF-R55 and TNF-R75), and interleukin-6 (IL-6) were measured by ELISA in nine female patients over a period of 2 yr. Compared to healthy controls, levels of TNF-alpha (median 47 pg/ml, range < 15-222 pg/ml), TNF-R55 (median 1.9 ng/ml, range 0.8-10.8 ng/ml), TNF-R75 (median 4.7 ng/ml, range 1.5-15 ng/ml) and IL-6 (median 3.5 pg/ml, range < 3.5-52 pg/ml) were significantly elevated in SLE patients (P < 0.0001 vs controls in all cases). There were strong correlations between TNF-alpha and its soluble receptors (P < 0.0001). Moreover, TNF-alpha and both TNF-Rs strongly correlated with clinical and serological parameters of disease activity, such as the European Consensus Lupus Activity Measurement (ECLAM) score, anti-dsDNA antibodies, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and anaemia (P < 0.0001 for all comparisons). TNF-alpha and TNF-R75 also correlated with IL-6 (P < 0.0001). However, no correlation between IL-6 and ECLAM was found, and the correlation of IL-6 with anti-dsDNA was relatively weak; in contrast, IL-6 correlated strongly with CRP and ESR (P < 0.0001). Although these data do not allow us ultimately to discriminate between beneficial and deleterious effects of TNF-alpha, they nevertheless suggest a central role for the TNF system in the pathophysiology of SLE.
These data clearly demonstrate production of cytokines by T cells in RA synovial tissue, indicating that activated T cells play a role in the pathophysiological events of RA.
Objective. To assess the significance of autoantibodies to RA33, the A2 protein of the heterogeneous nuclear ribonucleoproteins (hnRNP), and to the related hnRNP proteins Al, B1, and B2 in rheumatic diseases.Methods. Using a partially purified preparation of hnRNP-A and hnRNP-B proteins, sera from 303 patients with various rheumatic diseases were investigated by immunoblotting,. For the analysis of crossreactivities, autoantibodies were affinity purified by blot elution.Results. Anti-A2/R.A33 was found in 35% of rheumatoid arthritis (RA) patients, 38% of mixed connective tissue disease (MCTD) patients, 23% of systemic lupus erythematosus (SLIE) patients, and, apart from single exceptions, not in patients with other rheumatic diseases. All anti-A2/RA3:%positive sera were also reactive with B1 and B2, and anti-A2/RA33 antibodies cross-reacted with both proteins. Antibodies to hnRNP-A1 were found less frequently; moreover, the majority of anti-Al-positive sera also contained anti-A2/ RA33 antibodies. In anlti-Al, anti-A2/RA33 doublepositive sera, cross-reactivity between the 2 antibodies was generally observed. In SLE patients, the presence of anti-A2/RA33 was correlated with the presence of antiSupported in part by the Austrian Research Council (Fonds zur Forderung der Wissenschaftlichen Forschung).
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