AntiDNA

Anti-DNA antibodies are autoantibodies directed against deoxyribonucleic acid. The term most often refers to anti-double-stranded DNA antibodies (anti-dsDNA), but antibodies against single-stranded DNA (anti-ssDNA) are also recognized.

These antibodies are characteristic of systemic lupus erythematosus (SLE) and are found in a subset of patients with other autoimmune diseases or infections. Anti-dsDNA is relatively specific for SLE; anti-ssDNA is less specific.

Detection methods include ELISA, immunofluorescence assays such as the Crithidia luciliae test, and chemiluminescent immunoassays.

Clinical significance: anti-dsDNA levels often correlate with disease activity and lupus nephritis; rising titers can signal flares, while low or absent levels do not exclude SLE.

Pathophysiology: immune complexes formed by anti-dsDNA can deposit in glomeruli, triggering complement activation and inflammatory injury. The exact triggers of anti-DNA antibody production are not fully understood.

Limitations: not all patients with SLE have anti-dsDNA; some people with other diseases test positive; assay differences exist, and results should be interpreted in the clinical context.