'autoimmunization' originates from the prefix 'auto-' (Greek 'autos' meaning 'self') combined with 'immunization' (from Latin 'immunis' via Medieval/Modern Latin and English 'immunize'), where 'autos' meant 'self' and 'immunis' meant 'exempt'.

'autoimmunization' was formed in modern English in the 20th century by combining 'auto-' + 'immunization' (it developed alongside terms like 'autoimmunity' and the verb 'immunize'), and came into use in immunology literature to describe processes involving self-reactive immune responses.

Originally the components referred separately to 'self' and the act/process of 'immunizing'; over time the combined term came to be used specifically for the development or induction of immune responses directed at one's own tissues (autoimmunity).