Lymphocytotoxic antibodies in rheumatoid arthritis: relation to HLA-DR2 and rheumatoid factors.

During a Swiss multicenter study on HLA-antigens in rheumatoid arthritis (RA), the patients sera were tested for cytotoxic, complement fixing antibodies against autologous B- and T-lymphocytes (LCA). LCA were found in about 25% of the patients. Anti-B and cold-reacting LCA were more frequent than were anti-T and LCA reacting at 37 degrees. Most patients with anti-B had anti-T LCA as well. Among patients with LCA, 46.4% had the HLA-DR2 antigen as opposed to 21.2% of the patients without such antibodies (p = 0.0004). There was no difference between the two groups in regard to the other HLA-DR antigens. The patients with LCA had higher titers of rheumatoid factors and of antinuclear antibodies than those without these antibodies. There was no significant difference between the patients with LCA and those without in regard to severity of disease (radiological stage in relation to duration of disease), extra-articular involvement, the amount of circulating immune complexes, and erythrocyte sedimentation rate.