[The clinical significance of detecting the inhibition of topoisomerase I by the sera of patients with systemic scleroderma].

Topoisomerase I activity was studied by electrophoresis in agarose gel according to plasmid DNA relaxation. Sera from 62 patients with systemic scleroderma, 35 with Raynaud's syndrome, 8 with focal scleroderma, 15 with systemic lupus erythematosus, 20 with rheumatoid arthritis and 20 healthy subjects were examined. Out of 62 sera from SSD patients, anti-topoisomerase activity was found in 67.8% of cases. The test appeared positive in 79% of patients with diffuse and 63% with limited disease patterns. The mean age and disease standing were similar in the positive and negative groups. An increase of the skin count and more frequent occurrence of trophic disorders in patients with inhibition of the enzyme were recorded. 40% of the patients demonstrated the coincidence of the results with the use of the topoisomerase test and ELISA. In patients with other rheumatic diseases and in the healthy subjects, no inhibition of the enzyme was found.