Occurrence of antibodies to single-stranded DNA in ANA negative patients

Five patients with clinical features of a connective tissue disease most suggestive of systemic lupus erythematosus were found to have a negative ANA by conventional screening at 1/20 dilution on mouse liver. However, significant titres of antibodies to single-stranded DNA were detected using a double antibody radioimmunoassay. Thus, certain patients have antibodies to DNA restricted to single-stranded determinants as detected by radioimmunoassay with single-stranded DNA as antigen and a negative ANA test.