[Importance of the determination of antibodies to n-DNA in systemic lupus erythematosus and other rheumatic diseases (comparative study of radioisotope and immunoenzyme technics)].

Altogether 95 patients with systemic lupus erythematosus, 36 patients with rheumatoid arthritis, 10 with sclerodermia systematic, 10 with Bekhterev's disease, 9 with rheumatic fever, and 20 healthy persons were examined. An analysis of the results made it possible to establish that in SLE, sclerodermia systematic and Bekhterev's disease the frequency of detection of higher levels of antibodies to n-DNA using enzyme immunoassay and radionuclide methods was approximately the same. SLE patients were characterized by a 2-fold increase in the level of antibodies to n-DNA as compared to patients with sclerodermia systematic, Bekhterev's disease and rheumatic fever suggesting usefulness for differentiation of these diseases. In rheumatic fever and rheumatoid arthritis antibodies to n-DNA in minimal elevated levels were revealed more frequently under enzyme immunoassay than in radionuclide ones. In SLE high levels of antibodies to n-DNA under the method of radionuclide binding showed significant correlation with a decrease in complement hemolytic activity, high levels of circulating immune complexes, with a higher frequency of detection of the antinuclear factor, and reflected lupus nephritis severity. Enzyme immunoassay used for the detection of antibodies to n-DNA showed correlation of high levels of these antibodies with signs of developing cerebrovasculitis and pulmonary lesion.