IgG-anti-IgG antibodies in juvenile chronic arthritis.

IgG antiglobulins were measured in 117 children with seronegative juvenile chronic arthritis (JCA). 100 had active disease, and these had significantly higher levels of IgG antiglobulins (mean 0.45 +/- 0.16 micrograms/ml) than the control group (mean 0.25 +/- 0.16 micrograms/ml (p less than 0.01]. The inactive group of patients had a mean of 0.14 +/- 0.06 micrograms/ml, comparable to a group of cord bloods from normal births (mean 0.14 +/- 0.05 micrograms/ml). In the active patients there was no difference when subdivision was made according to their mode of onset into pauciarticular, polyarticular, or systemic.