Rheumatoid Arthritis Research Today is a free monthly online journal that collates and summarizes the latest research about Rheumatoid Arthritis, including details on treatment, symptoms, causes, medication. | ||||||||
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Influence of HLA-DR genes on the production of rheumatoid arthritis-specific autoantibodies to citrullinated fibrinogen.Auger I, Sebbag M, Vincent C, Balandraud N, Guis S, Nogueira L, Svensson B, Cantagrel A, Serre G, Roudier J INSERM UMR 639, La Conception Hospital, Faculté de Médecine, 27 Boulevard Jean Moulin, 13005 Marseille, France. OBJECTIVE: Antibodies directed against citrullinated fibrinogen are highly specific for rheumatoid arthritis (RA). This study was undertaken to test whether RA-associated HLA-DR alleles are associated with anti-citrullinated fibrinogen in RA patient sera and whether replacement of arginyl by citrullyl residues on fibrinogen peptides modifies their binding to HLA-DR molecules and their recognition by T cells. METHODS: Antikeratin, antifilaggrin, and anti-citrullinated fibrinogen antibodies were assayed in RA patients who had undergone HLA-DR typing. Direct assays were performed to investigate binding of citrullinated or native fibrinogen peptides (encompassing the entire alpha- and beta-chains of fibrinogen) to purified HLA-DR molecules. T cell proliferative responses to citrullinated or native fibrinogen peptides were measured in RA patients and controls. RESULTS: HLA-DRB1*0404 was associated with anti-citrullinated fibrinogen in RA sera (P = 0.002). For the RA-associated alleles HLA-DRB1*0401 and HLA-DR1, there was a nonsignificant trend toward association (P = 0.07). Multiple peptides from the alpha- and beta-chains of fibrinogen bound many HLA-DR alleles; DRB1*0404 was the best fibrinogen peptide binder. Citrullination did not influence fibrinogen peptide binding to HLA-DR or fibrinogen peptide recognition by T cells. Peripheral blood T cells that recognized native or citrullinated fibrinogen peptides were common in RA patients but not in healthy controls. CONCLUSION: The RA-associated HLA-DRB1*0404 allele is also associated with production of antibodies to citrullinated fibrinogen. DRB1*0401 and DRB1*01 tend to be associated with anti-citrullinated fibrinogen, but this is not statistically significant. Citrullination of fibrinogen peptide does not influence peptide-DR-T cell interaction. Finally, T cell proliferation in response to citrullinated or uncitrullinated fibrinogen peptides is frequent in RA patients and very infrequent in controls. Published 3 November 2005 in Arthritis Rheum, 52(11): 3424-32.
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