Is It Safe To Have IVIG Injection For Dermatomyositis?

My sister is diagnosed with dermatomyosits 9 months ago and was given pulse therapy deu to which CPK came back to normal but recently it went up again even though she is taking wyselon 20Mg. Now doctors have suggested going for an injection/IVIG which will cost 1lakh but more than cost I am worried about the side effects. Pls advise