Serodiagnosis and immune profile in rheumatoid arthritis.

One hundred and seventy-five cases of clinically diagnosed rheumatoid arthritis, 82 non-rheumatoid cases suffering from various other diseases and 40 healthy normal controls were investigated for detection of rheumatoid factor, quantitation of serum immunoglobulin, demonstration of antinuclear antibody (ANA) and LE cell phenomenon. Microlatex agglutination test of serum for rheumatoid factor (RF) showed 64% positivity in rheumatoid group and 1.2% positivity in non-rheumatoid group. All three immunoglobulins (IgG, IgM, IgA) were found to be raised in serum of patients with rheumatoid arthritis, whereas only IgA level was elevated in serum of patients with non-rheumatoid diseases. ANA and LE cell phenomenon were observed in 3.4% and 2.8% cases respectively in cases of clinically diagnosed rheumatoid arthritis who had been suffering from severe active rheumatoid arthritis. In non-rheumatoid group RF was positive in significant titre in only one case of leprosy. Synovial fluid and synovium were found to be heavily infiltrated by plasma cells and lymphocytes. RF appears first in synovial fluid and then in serum. Hence RF titre in blood may not attain significant level for the first several months.