ANTIBODIES TO A 15-KD NUCLEAR ANTIGEN IN PATIENTS WITH JUVENILE CHRONIC ARTHRITIS AND UVEITIS

Young girls with a pauciarticular onset of juvenile chronic arthritis and circulating antinuclear antibodies are at risk for chronic uveitis. The actual nuclear antigen for these antinuclear antibodies has not been defined. Conventional laboratory techniques, such as counter immunoelectrophoresis, have shown that antibodies to well defined "extractable nuclear antigens" (eg, RNP, Sm, SS-A, and SS-B) are not present in patients with juvenile chronic arthritis. Therefore, other, previously unknown nuclear antigens may be involved. Sera of 64 patients with juvenile chronic arthritis, including 22 patients with chronic anterior uveitis, were studied using the immunoblotting technique to characterize the nuclear antigens. Antinuclear antibodies were present in 12 (55%) of the 22 patients with uveitis, and only in six (14%) of the 42 patients without chronic anterior uveitis. With the immunoblotting technique, antibodies to a 15 kD nuclear antigen were found in 10 (45%) of the 22 patients with chronic anterior uveitis, whereas only two (5%) of the 42 patients without chronic anterior uveitis showed these antibodies (P < 0.001). Only clearly visible and reproducible lines in the immunoblotting patterns were studied. This may provide a diagnostic tool for the early detection of uveitis and means for further pathogenetic studies.