Persistent and transient IgA deficiency in juvenile rheumatoid arthritis.

Twenty-five children with serum IgA levels of less than 0.1 g/l (below the 2.5% confidence limit at 2 years of age) were found among approximately 350 cases of juvenile rheumatoid arthritis (JRA). During follow-up, 10 of them proved to have persistent IgA deficiency, 13 were classified as having transient IgA deficiency, and 2 had consistently low serum IgA. Transient IgA deficiency occurred during treatment, in 9 cases with gold and in 2 with antimalarials. The gold-induced IgA deficiency usually developed abruptly soon after institution of gold therapy, and its duration varied from a few months (4 cases) to several years (3 cases). In 6 cases a low IgA level has returned to normal despite continuing gold therapy. In half the patients with persistent IgA deficiency the course has been mild and oligoarticular, and after a mean duration of 8.8 years only one has active disease. In contrast, in the patients with transient IgA deficiency the disease was characterized by early onset (mean age 3.0 years), a polyarticular course (10/13) and prolonged activity (7/13, mean duration 9.6 years). Coeliac disease was diagnosed in 2 patients, both with persistent IgA deficiency.