[Morphologic analysis of synovial effusion in rheumatoid arthritis. I. Light microscopy--cytology, histochemistry and...

Inflammatory synovial fluid in patients with rheumatoid arthritis contained IgG, IgM and C3 component of complement, unspecific esterase and acid phosphatase and affinity to Pisum sativum agglutinin (PSA). Various forms of a degeneration of polymorphs, giant non-lymphoid mononuclear cells with cerebriphorm nuclei in different stages of phagocytosis and lymphocytes, sometimes with numerous nuclear invaginations, were found. All the cells of synovial fluid contained IgG, not the IgM. C3 component of complement was limited to non-lymphoid non-lymphoid mononuclear cells. Both the enzymatic activities were especially stressed in polymorphs. PSA was bound to all cells.