SPECIFICITY AND CLASS DISTRIBUTION OF FC-GAMMA-R-SPECIFIC AUTOANTIBODIES IN PATIENTS WITH AUTOIMMUNE-DISEASE

To investigate the prevalence of autoantibodies directed against Fcgam maRII (CD32) and FcgammaRIII (CD16), 151 serum samples from patients w ith different autoimmune diseases and 25 samples obtained from healthy individuals were assayed by ELISA on microtiter plates coated with re combinant truncated FcgammaRII and FcgammaRIII protein. Class specific ity was defined with anti-IgG, anti-IgM, and anti-IgA reagents. High t iters of circulating IgM autoantibodies reacting with both FcgammaRII and FcgammaRIII were characteristic for SLE and rheumatoid arthritis p atients. Sera from patients with Raynaud's syndrome showed predominant ly IgG reactivity with FcgammaRIII. Sera from patients with progressiv e systemic sclerosis showed both IgG and IgM FcgammaRII and FcgammaRII I reactivity. Many patients diagnosed with degenerative osteoarthritis also had IgG autoantibodies, directed primarily against FcgammaRII wi th lesser reactivity toward FcgammaRIII. Further study is needed to co rrelate these findings to clinical characteristics of the different di seases.