Hi Tony,
I have had IVIG a few times when I was admitted to hospital for an increase in weakness and difficulty breathing and swallowing. In January 2010 I weaned off of pred after being on it for a year. My dr agreed that an IVIG schedule was a reasonable treatment plan. In Feb 10 I started my monthly treatments. I go to the hospital for two days a month as an out patient to receive the IVIG. As of today I have had four months worth of treatments.
I take Imuran and have been on it since Nov. 08. My dr originally told me that the Imuran takes at least 6-9 months to start to work. It is really hard to say what is working at what time. In between I have had the full sternotomy thymectomy in Feb. 09.
I believe that the meds of Imuran & Mestinon and the IVIG are working together to keep me going. Prior to diagnosis I was pretty much in bed or on the couch because of severe weakness.
Not really sure if this is helpful.

Melanie