That's immunity.
Auto in auto-immunity is not the "auto" from "automatic" but the ancient Greek "auto-" meaning "self-".
So, auto-immunity is like self-fighting (fighting yourself). You don't want that.
(which is also from the Greek auto meaning self)
That's just immunity. Auto-immunity is "what your body does to fight itself off". You generally don't want to be fighting yourself off.
These are also difficult diseases to treat – often involving biologics (large molecules administered by injection or IV). T1D is insulin, obviously, but the first big blockbuster medications in the space were Humira and Remicade, monoclonal antibodies, which are powerful immune-system suppressants but more selective (and therefore, relatively speaking, safer long-term) than systemic steroids like prednisone.
” Autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other body normal constituents.”