Demonstration of antibodies to denatured type I and type II collagen in juvenile rheumatoid arthritis, Still's syndrome and controls by [14C] collagen radioimmunoassay.

From 88 sera of patients with juvenile rheumatoid arthritis 30.6% showed antibodies to denatured type I collagen an 31.8% antibodies to type II collagen, a percentage which corresponds to radioimmunoassay results in adult RA. Rheumatoid factors were demonstrated with Waaler-Rose test in 14.7% and with latex test in 6.8% of investigated patients. Results of investigations with collagen types I and II correlated in 73.7%. Whilst type I collagen antibodies were found with equal frequency in active and non-active stages, type II antibodies were twice as frequent in active stages as in non-active stages. Sixteen sera of children with non-rheumatoid diseases had no collagen antibodies. JRA sera and controls differed with statistical significance in regard to collagen antibodies. 36 sera of children with Still's syndrome showed antibodies to type I collagen in 13.8% and antibodies to type II collagen in 33.3%. Both types of antibodies appeared more frequently in clinically active stages. The sera differed from controls with statistical significance in regard to collagen antibodies.