Autoantibodies to DNA topoisomerase II in juvenile rheumatoid arthritis.

Sera from 58 children with juvenile rheumatoid arthritis were examined for the presence of antibodies to DNA topoisomerase II. Eight sera were reactive in immunoblotting with purified human topoisomerase II and a protein encoded by a cloned cDNA expressed in Escherichia coli which represents the carboxy-terminal domain of the human enzyme. In addition, the sera detect topoisomerase II in mitotic chromosomes and chromosome scaffolds. Five of the sera bind to the native enzyme in solution and deplete such solutions of the active enzyme. All eight sera also contain antibodies to nuclear antigens other than topoisomerase II.