Autoantibodies to topoisomerase I (Scl-70): analysis by gel diffusion, immunoblot, and enzyme-linked immunosorbent assay.

Anti-topoisomerase I autoantibodies (anti-topo I, anti-Scl-70) are associated with proximal scleroderma and are of prognostic significance in patients with Raynaud's disease. To establish a highly sensitive and specific system for the detection of anti-topo I, we have investigated sera from 409 patients and controls by Ouchterlony gel diffusion, Western immunoblot on chromosome proteins, and solid-phase enzyme-linked immunosorbent assay (ELISA) with purified topoisomerase I as antigen. The ELISA was more sensitive than the gel diffusion technique and was more specific than the Western immunoblot, while the immunoblot may identify additional autoantibodies.