How long do you continue IVIG for myositis patients in remission on that therapy?  

Typical total duration of IVIG is about 1-2 years. If someone is in remission, I will decrease IVIG to 1 gm/kg monthly dose.  If still in remission for 3 months, I decrease to 1 gm/kg every other month for 2 more cycles. If still in remission, you could either stop or do 1-2 doses every 3 month...