Antibodies to single-stranded DNA ( anti-ssDNA ) are detected both in rheumatic diseases and in other somatic and infectious diseases. However, the highest frequency of detection of elevated levels of these antibodies is observed with SLE (87% in the active phase and up to 43% in the remission period) and scleroderma, rheumatoid arthritis, Sjogren's syndrome. AT to ssDNA play a role in the pathogenesis of kidney damage in lupus nephritis. Antibodies to single-stranded DNA can be increased with many inflammatory, oncological diseases, accompanied by destruction of tissues. The non-specificity of the detection of these antibodies significantly limits their use in clinical practice.