Immunophotometric analysis of immunoglobulin synthesis and deposition in synovial membranes of patients with rheumatoid arthritis.

Immunophotometrical measurements of the Ig synthesis of plasma cells in joint capsules of patients with rheumatoid arthritis and osteoarthritis were compared. Patients with rheumatoid arthritis showed higher mean values in the single plasma cell than patients with osteoarthritis for all Ig isotypes except IgG. These results are indicative for a B cell activation with increased synthesis of Ig in RA.