Autoantibodies in childhood connective tissue diseases and in normal children.

The prevalence of nine serum autoantibodies has been studied in 117 children with various connective tissue disorders and in 134 normal controls. In juvenile rheumatoid arthritis rheumatoid factor was present in 5%, and antinuclear factor in 4%, compared with an incidence of 4% and 0% respectively in controls. In Henoch-Schönlein purpura there was little evidence of associated autoimmune disorder. Gastric parietal cell and thyroid microsomal antibodies were found in 9% and 10% of our control population, but the significance of this is not clear. It is concluded that in children the presence or absence of autoantibodies as diagnostic criteria should be interpreted with the greatest caution.