Serum immunoglobulin and complement interrelationships in juvenile rheumatoid arthritis.

Patients with juvenile rheumatoid arthritis (JRA) were compared with a matched control group for the presence and levels of IgG, IgM, IgA, IgE, IgD, C3, C4, and rheumatoid factor. In the majority of patients (86.1 to 94.4%) the distributions fell within the normal ranges of the control group. In JRA, older age appears to have a significant relationship for increased IgE levels. Levels of IgE and IgD do not appear to be related to the presence or activity of JRA. Significantly elevated levels of IgG, IgA, and C4 were found in active disease while elevated IgM levels are characteristic of the disease itself.