A clinico-immunological study of serum and synovial fluid antinuclear factors in rheumatoid arthritis and other arthritides.

Samples of serum and synovial fluid from 161 patients with various forms of arthritis have been examined for the presence of antinuclear factors (ANF). In rheumatoid arthritis 28% of patients had ANF in their serum, and in 22% ANF was found in the synovial fluid. In ten patients ANF was present in the serum alone. In three patients ANF was present in only the synovial fluid, and in one of these patients the finding of ANF in only one of two joints examined is adduced as evidence in favour of local production of ANF in synovial tissue. The ANF was present in the serum and synovial fluid as IgM in 75%, as IgG in 22% and as IgM/IgG in 3% of rheumatoid arthritis patients.