Solid-phase radioimmunoassay detection of rubella virus IgG antibody in serum and CSF of patients with multiple sclerosis.

Low levels of rubella virus IgG antibody have been detected in cerebrospinal fluid (CSF) specimens of multiple sclerosis (MS) patients by a solid-phase radioimmunoassay (RIA) previously developed for testing of clinical serum samples. Paired serum and CSF specimens of 36 MS patients and 12 control patients were analyzed. Of those MS patients which had negative CSF titers in the rubella hemagglutination inhibition (HAI) test, 90% (11/12) were found to have rubella IgG antibody by the RIA method. In specimens found to contain rubella IgG antibodies by both methods, the RIA test was approximately 15 times more sensitive than the rubella HAI test. The results presented suggest that a considerable portion of MS patients have significantly reduced serum/CSF rubella IgG antibody ratios, indicating that there is a local production of rubella antibodies in the central nervous system of these patients.