The significance of antinuclear antibodies in juvenile rheumatoid arthritis associated with chronic bilateral iridocyclitis.

Serum samples from 8 children with juvenile rheumatoid arthritis (JRA) and chronic bilateral iridocyclitis were significantly distinguished from 5 children with JRA and no eye symptoms by the presence of large immune complexes (IC) greater than 22S, IgM antinuclear antibodies (ANA), IgG granulocyte-specific (GS-) ANA, C3 fixing ANA, and IgM anti-IgG. One serum with and two sera without IC greater than 22S, all from patients with iridocyclitis, were fractionated by rate zonal ultracentrifugation. Each fraction relevant for the study was separately concentrated and reexamined. In one of the sera without IC greater than 22S this technique exposed the presence of IgA GS-ANA not detectable in the corresponding whole serum. IgG ANA were precipitated in an area with higher molecular weight than the one for IgG indicating the presence of aggregated IgG ANA. Fractionation of the serum with IC greater than 22S demonstrated IgM GS-ANA not present in whole serum. The results support previous suggestions that ANA may be involved in the pathogenesis of chronic iridocyclitis and may explain why ANA (in particular C3 fixing ANA) negative patients with JRA rarely develop chronic iridocyclitis.