The amyloidosis of juvenile rheumatoid arthritis - comparative studies in Polish and American children II. Serum immunoglobulins, kappa and lambda light chain and C3 levels.

The concentration of serum IgG, IgM, IgA, IgD, IgE and complement C3 as well as Kappa and Lambda free and bound light chains were determined in sera from 21 amyloidotic Polish children with juvenile rheumatoid arthritis (JRA), Polish and American children with JRA, and control children from a Polish population. Comparable concentrations of IgG, IgM, IgA, IgE and C3 were found in amyloidotic children when compared to Polish JRA children with active polyarticular disease. However, the amyloidotic Polish children with JRA had significantly higher levels of IgG, IgM, IgA, IgE and complement C3 fraction when compared to American JRA children. The levels of IgA and IgE were significantly elevated in amyloidotic and Polish JRA populations when compared to American JRA patients. Free immunoglobulin light chains were not found in the sera of any of the children tested in this study. However, in the patients with amyloidosis, significantly diminished levels of bound Kappa and Lambda light chains were found.