Both terms are medical terms and Morgana translated them correctly.
An autoimmune (= self-immune) disease is a (sometime very serious) illness when our immunitary system reacts against cells of our own organism. These diseases are quite common (particularly thyroid autoimmune disorders), but very difficult to cure.
The English words are: opioid, autoimmune, and immune system. ("Immunitary" doesn't exist; and I don't think "self-immune" is used, though I could be wrong).