Personal anecdote: I have Graves disease, and it didn't flare up until a couple years after I finished immune therapy for a variety of severe allergies. The allergies are much better! But my immune system got bored, or something. Correlation vs causation though... causation makes a lot of sense when living it, but it's not proof.

I'm also quite certain my great-grandmother had this same thing, but no would have been able to diagnose her as anything but excessively thin back then. (It severely increases your metabolism and can cause osteoporosis.)