WA IDIOTYPE IN SEROPOSITIVE RHEUMATOID-ARTHRITIS

Antibodies against cross-reactive idiotypes (CRIs) may prove useful as phenotypic tracers of immunoglobulin variable region genes (V(H) or V (L)). CRIs of human rheumatoid factors (RFs) seem to be useful in the elucidation of the incidence and structural characteristics of the lat ter. Anti-Wa CRI antibodies were produced and an enzyme immunoassay wa s developed to test polyclonal RFs isolated from sera of 20 rheumatoid arthritis (RA) patients, 7 males and 13 females, aged 17 to 74 years. Seventeen patients had clinically active disease and three were in re mission. Disease duration ranged from 1 to 25 years and RF titers rang ed from 1: 160 to 1:640. The immunoassay could detect as little as 8 n g of a monoclonal purified WaRF and positive results were found in 30% of patient sera. Therefore, we may conclude that at least part of the RFs seen in RA patients derives from germ line genes.