autoantibodiesare

Autoantibodies are antibodies produced by the immune system that target the body's own proteins, nucleic acids, or cellular components. They arise when tolerance to self-antigens fails, due to genetic susceptibility, environmental triggers, or immune dysregulation. Autoantibodies can be present in healthy individuals at low levels, but higher titres and certain specificities are associated with autoimmune diseases.

Pathogenic or clinically useful: Some autoantibodies directly cause tissue injury through receptor blockade, enzyme inhibition, or immune complex deposition (as in systemic lupus erythematosus, rheumatoid arthritis). Others serve as disease markers, aiding diagnosis and prognosis rather than causing symptoms.

Common examples include antinuclear antibodies (ANA), which react with nuclear components and are common in lupus and other autoimmune diseases; anti-dsDNA and anti-Smith antibodies are more specific for lupus; antiphospholipid antibodies are linked to thrombosis; rheumatoid factor and anti-CCP antibodies are used in rheumatoid arthritis; autoantibodies to thyroid peroxidase (TPO) and thyroglobulin in autoimmune thyroid disease; autoantibodies against acetylcholine receptor in myasthenia gravis.

Detection relies on methods such as indirect immunofluorescence to detect ANA, ELISAs or line immunoassays for specific autoantibodies. Test results must be interpreted in clinical context, as autoantibodies may be present in infections, malignancies, or healthy aging, and not all patients with a given antibody have active disease. Titres, patterns, and combinations influence diagnosis and management.

Autoantibody testing informs diagnosis, prognosis, and treatment choices, including immunosuppressive therapy, targeted biologics, or monitoring for complication risks. Ongoing research seeks to clarify pathogenic roles of individual autoantibodies and to improve assay specificity and clinical interpretation.