autoimmunen

Autoimmunity refers to a misdirected immune response in which the body's defenses target its own tissues. It exists on a spectrum from harmless autoantibodies detected in healthy people to full‑fledged autoimmune diseases that cause tissue injury and organ dysfunction. Autoimmune conditions arise when mechanisms that normally maintain self-tolerance fail, allowing autoreactive B cells, T cells, and autoantibodies to drive inflammation.

Causes and mechanisms are multifactorial. Genetic susceptibility, especially certain HLA gene variants, increases risk. Environmental triggers such as infections, drugs, or toxins can initiate or boost autoimmunity in predisposed individuals. Defects in immune regulation, including impaired regulatory T cells, contribute to loss of tolerance. Processes like molecular mimicry, epitope spreading, and bystander activation help sustain autoimmune responses.

Autoimmune diseases are broadly classified as organ‑specific or systemic. Organ‑specific examples include autoimmune thyroiditis and type 1 diabetes, where the immune attack concentrates on a single organ. Systemic diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and Sjögren's syndrome, involve multiple organs and tissues.

Diagnosis relies on clinical features supported by laboratory tests, including autoantibodies, organ function tests, imaging, and sometimes biopsy. Management aims to reduce immune activity and control symptoms, often through corticosteroids, immunosuppressive drugs, and targeted biologic therapies. Treatment plans are individualized and may require long‑term monitoring for effectiveness and adverse effects.

Epidemiology varies by disease but autoimmune conditions collectively affect millions worldwide and are more common in women for many disorders. Ongoing research seeks to understand tolerance, genetic and environmental risk factors, and ways to predict, prevent, and personalize treatment.