Dr. Filinov who is one of very few actually doing research on the subject and has used it clinically for a long time claims to have cured a lot of ppl with autoimmune diseases thanks to dry fasting and a strict preparation + refeeding schedule. You could get his book, says more about how many days to be expected for it etc.
However, all can´t be cured, and from what I understand odds are lower the more/longer you already have tried to medicate it, depending on the type of disease and meds, and how far it has progressed. Also, best results are usually obtained after one or repeated long dry fasting sessions (like 11 days) which isn´t really recommended for just anyone to try and especially without medical supervision. Just to be a bit down to earth about it, but I think it´s well worth trying as long as you don´t have meds that are dangerous to pause, since you could most of the time improve your overall well being and perhaps temporarily get rid of the symtoms even if it doesn´t get completely cured.