Clinical significance of anti-double-stranded DNA antibodies detected by a solid phase enzyme immunoassay.

A solid phase enzyme immunoassay (EIA) detected anti-double-stranded (ds) DNA antibodies in 88% of sera from patients classified clinically as having active systemic lupus erythematosus (SLE) without renal symptoms and 93% with renal disease. Fifty-six percent of sera from patients with inactive SLE were EIA positive for anti-dsDNA antibodies. The EIA had a sensitivity and specificity comparable to radioimmunoassay (RIA) and hemagglutination for patients with active SLE with or without renal disease, but it detected anti-dsDNA antibodies more frequently in patients with inactive SLE than the latter procedures. Precipitating antibodies detected by counterimmunoelectrophoresis (CIE) were less common in patients with renal disease (23% incidence) than clinically active patients without renal disease (79% incidence). Twenty-four SLE sera with elevated levels of C1q binding showed a 96% concordance for a positive EIA for anti-dsDNA antibodies in contrast to 66% concordance by RIA or hemagglutination. These findings suggest that the EIA is a sensitive and specific method for detection and measurement of anti-dsDNA antibodies. Several clinical applications of the EIA are discussed.