Autoantigene

Autoantigen, sometimes written autoantigene, is a self-derived molecule that can be recognized by the immune system as an antigen. In healthy individuals, central and peripheral tolerance normally suppress autoreactive responses. In autoimmune diseases, certain self-antigens become targets of autoantibodies and autoreactive T cells, causing inflammation and tissue injury.

Autoantigens may become targets through release from damaged tissue, exposure in inflamed environments, and post-translational modifications that create neoepitopes. Mechanisms such as molecular mimicry, epitope spreading, and genetic susceptibility contribute to loss of tolerance.

Common autoimmune targets include dsDNA and other nuclear antigens in systemic lupus erythematosus; thyroid antigens such as thyroglobulin and thyroid peroxidase in autoimmune thyroid disease; acetylcholine receptor in myasthenia gravis; citrullinated peptides in rheumatoid arthritis; insulin and GAD65 in type 1 diabetes.

Clinical relevance: autoantibodies against autoantigens are used in diagnostics (ELISA, immunofluorescence). Their presence supports diagnosis and monitoring in autoimmune diseases, but autoantibodies can be detected in healthy individuals or precede disease onset.

Notes: The term autoantigen is standard; autoantigene is a less common variant used in some contexts or languages.