POSTSTREPTOCOCCAL ANTIMYOSIN ANTIBODY IDIOTYPE ASSOCIATED WITH SYSTEMIC LUPUS-ERYTHEMATOSUS AND SJOGRENS-SYNDROME

Anti-myosin antibodies are to found in acute rheumatic fever (ARF), a sequela of group A streptococcal infection. An antiidiotypic serum was produced that was specific for idiotopes expressed by anti-myosin ant ibodies in ARF (anti-Myl). Studies indicated that idiotypic determinan ts detected with this serum were present in anti-myosin antibodies and absent from normal human immunoglobulins that lacked specificity for myosin. Anti-Myl was tested against sera from patients with other type s of autoimmune diseases as well as uncomplicated streptococcal infect ions. Sera from systemic lupus erythematosus (SLE), Sjogren's syndrome (SS), and poststreptococcal acute glomerulonephritis patients demonst rated idiotypic reactivity with anti-My 1. Affinity-purified anti-myos in antibodies from SLE, SS, and ARF sera also reacted strongly with an ti-Myl, indicating that immunoglobulins produced in these diseases sha re idiotypic determinants. The data demonstrated an association of the Myl idiotype with poststreptococcal sequelae and the two autoimmune d iseases SLE and SS.