Immunologic studies of juvenile rheumatoid arthritis.

Antigammaglobulins of the IgG, IgA and IgM classes, and whole hemolytic complement and complement components were measured in the sera and synovial fluid of patients with juvenile rheumatoid arthritis. Two groups of patients were distinguishable using these measurements. A group of patients with chronic active disease had elevated levels of IgG, IgA and IgM antigammaglobulins and relative depressions of complement and complement components in sera and synovial fluid. Another group of patients with acute self-limited disease had elevated levels of IgG and IgA antigammaglobulins and serum complement and negative latex fixation tests in association with disease activity. These values returned to normal with clinical remissions.