Rubella antibody levels in juvenile rheumatoid arthritis

Increased rubella antibody titres have been reported in patients with juvenile rheumatoid arthritis (JRA) and it has been suggested that rubella virus may be of importance in the aetiology or pathogenesis of the disease. In the present study, rubella and rubeola antibody titres in 85 patients with JRA were compared to age- and sex-matched controls. 41% of the patients did not have rubella antibody, but the geometric mean titre of those with JRA who had antibody was slightly higher than that of the controls with antibody (58-9 against 42-7; P less than 0-05). The level of rubella antibody titre correlated with serum IgG levels. There was no difference in rubeola antibody titres between patients and controls, and rubeola antibody did not correlate with serum IgG. Fifteen JRA patients developed rubella antibody after rubella vaccine or natural disease. This did not result in unusually high antibody titres and was associated with a mild exacerbation of symptoms in only two patients. This study suggests that the slight increase in rubella antibody in JRA is a nonspecific manifestation of increased immunoglobulins.