What does autoimmune mean?
The adjective "autoimmune" describes an immune system that malfunctions by turning against the very body it is meant to defend. In a normal immune response, specialized cells recognize and attack foreign invaders such as bacteria and viruses; in an autoimmune response, this recognition fails, and the body's own healthy cells and tissues are treated as threats. The term appears most often as a modifier in medical language — as in "autoimmune disease," "autoimmune disorder," or "autoimmune response" — and names a broad category of illnesses that includes rheumatoid arthritis, type 1 diabetes, lupus, and multiple sclerosis. Because it is a technical term, it carries a clinical, formal register rather than everyday tone, though it has become increasingly familiar to the general public as awareness of these chronic conditions has grown. The word combines the Greek-derived prefix "auto-," meaning "self," with "immune," from Latin roots relating to exemption or protection. Understanding "autoimmune" is useful both for interpreting medical information accurately and for appreciating a striking biological paradox: sometimes the body's greatest protector becomes its own adversary.
adjectiveRelating to or caused by an immune response in which the body's immune system mistakenly attacks its own healthy cells and tissues.
- Relating to or caused by an abnormal immune response directed against the body's own healthy cells and tissues.
"Lupus is an autoimmune disease in which the immune system attacks the body's own organs."
"Rheumatoid arthritis is one of the most common autoimmune diseases, affecting millions worldwide."
"Doctors ran a series of tests to determine whether her symptoms pointed to an autoimmune condition."
In autoimmune conditions, your body's own defense system becomes the attacker — the same army built to protect you turns its weapons inward.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of autoimmune
"Autoimmune" combines the Greek prefix "auto-," meaning "self," with "immune," which derives from Latin "immunis," meaning exempt from public service or duty. The concept emerged in early twentieth-century medicine, as researchers began recognizing cases where the immune system attacked the body's own tissues. Related terms sharing these roots include "immunity" and, through the Latin "munis" (duty, service), words like "community" and "municipality."
Related word forms
How autoimmune is actually used
"Autoimmune" is used almost exclusively in medical and scientific contexts and is nearly always found attributively before a noun (e.g., autoimmune disease, autoimmune reaction); standalone predicative use is rare.
Easily confused with autoimmune
"Autoimmune" is the adjective describing the self-attacking immune process, while "autoimmunity" is the noun referring to that state or phenomenon itself.