autoimmune (adj.)

also auto-immune, "arising from an abnormal immune response to a normal body part," 1952, from auto- + immune. Related: Autoimmunity, attested by 1903 as "immunity, natural or acquired, effected by the unaided powers of the organism, independent of external agencies." Modern sense of "immune responses of an organism against its own healthy cells and tissues" is from 1950s.