DEVELOPMENT OF THE ANTI-RO AUTOANTIBODY RESPONSE IN A PATIENT WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. To characterize the initial events in anti-Ro production by a patient with systemic lupus erythematosus, in whom this autoantibod y is developing.Methods. The immune response to the Ro ribonucleoprote in and other autoantigens were studied by enzyme-linked immunosorbent assay for IgG and IgM, by isoelectric focusing, and by inhibition stud ies to determine apparent avidity. Results. The patient's sera showed an oligoclonal response to Ro that increased in complexity and affinit y with time. IgM anti-Ro appeared shortly before IgG anti-Ro, and disa ppeared as IgG anti-Ro increased in titer and affinity. IgG antiriboso mal P autoantibodies also appeared during the patient's course, but in contrast to anti-Ro, were not proceeded by IgM antiribosomal P. Concl usion. These data are consistent with the Ro autoantigen being present ed and processed in a manner similar to heterologous antigen, and with differences in the mechanisms that lead to the production of IgG anti -Ro autoantibodies as opposed to antiribosomal P autoantibodies.