Autoantibodies in chronic arthritis of childhood: relations with each other and with histocompatibility antigens.

BACKGROUND Studies have shown the presence of either antibodies to histone or anticardiolipin antibodies in some forms of childhood chronic arthritis. The relation between these autoantibodies has not been previously reported, however, and the immunogenetics of their association with childhood arthritis has not been studied. METHODS The interrelation of fluorescent antinuclear antibodies, antibodies to histone, and anticardiolipin antibodies and their associations with histocompatibility antigens (HLA) were studied in 114 children with chronic arthritis (45 children with pauciarticular onset juvenile chronic arthritis (JCA), 22 with polyarticular onset JCA, 13 with systemic onset JCA, and 34 with juvenile psoriatic arthritis (JPsA). Antibodies to histone and anticardiolipin antibodies were determined in 108 children. HLA antigens (A, B, C, and DR) were studied in the 83 white children. RESULTS Antibodies to histone occurred in 0% (systemic onset JCA) to 42% (uveitis negative, pauciarticular onset JCA), and anticardiolipin antibodies in 26% (JPsA) to 55% (polyarticular onset JCA) of patients. Only 12 patients (11%) had both antibodies to histone and anticardiolipin antibodies. Neither antibodies to histone nor anticardiolipin antibodies associated with the type of arthritis. Neither of these antibodies alone associated with uveitis. Antibodies to histone were associated with HLA-A2, probably reflecting the known association of HLA-A2 with pauciarticular onset JCA. There was no other HLA association. Fluorescent antinuclear antibodies occurred most often in patients with uveitis; however, the occurrence of fluorescent antinuclear antibodies in patients with pauciarticular onset JCA (the group most at risk for uveitis) was not significantly greater in children with uveitis than in those without uveitis (100 and 88% respectively). CONCLUSIONS Although antibodies to histone and anticardiolipin antibodies often occur in serum samples from patients with JCA and JPsA, they rarely occur together. Their presence does not associate with uveitis. This study did not show any strong evidence that production of either antibodies to histone or anticardiolipin antibodies in patients with JCA or JPsA is under the control of the histocompatibility locus.