Antinuclear Factors in Synovia

Abstract

Antinuclear factors (ANF) of one or more immunoglobulin classes were identified in synovia of nine of 21 patients with rheumatoid arthritis. In most instances, ANF were also present in serum, but in some patients ANF were identified only in synovia. Rheumatoid factor (RF) was detected in serum or synovia of 17 of 21 patients with rheumatoid arthritis. The levels of synovial hemolytic complement and second component of complement (C'2) activity in patients with rheumatoid arthritis was consistently reduced. ANF, RF, and depressed levels of synovial hemolytic complement or C'2 activity were occasionally found in patients with other arthritides. Synovial leukocytic inclusion bodies containing γG, γM, and β_1cglobulin were more frequent in four patients with rheumatoid arthritis than in three patients with other arthritides. Reaction of antinuclear factors in synovia with nuclear antigens may contribute to the depressed synovial complement and complexes of these constituents may be present in some rheumatoid synovial inclusion bodies.