Anti-DNA antibodies in autoimmune disorders by ELISA using nylon as the solid phase.

A rapid, simple and highly sensitive enzyme-linked immunosorbent assay (ELISA) utilizing nylon as the solid support is described for the detection of anti-DNA antibodies in autoimmune disorders. The optimal reaction conditions were established with an anti-DNA antibody-positive SLE serum. Fifty-three percent of systemic lupus erythematosus patients, 29 percent of patients with systemic lupus erythematosus with overlapping progressive systemic sclerosis and 10 percent of progressive systemic sclerosis patients were positive for anti-DNA antibodies. The sensitivity of the method was compared with passive hemagglutination and fluorometric assays, the latter using ethidium bromide as intercalating dye. The method described is specific, reproducible and convenient for use in clinical laboratories where large numbers of samples are to be screened for the detection of anti-DNA antibodies. The procedure requires small quantities of antigen or antibody and is, therefore, highly economical.