Rita,
This is disturbing news. You are not the first or only patient to have had an episode despite being on IVIG, but we need to get to the bottom of these relatively rare incidents.
First, request and authorize in writing that the ICU send your 1st and 2nd day blood samples to Dr. Druey at NIH. He is always looking for episode samples -- especially now, that most of us are not having episodes anymore. Hospitals usually save blood samples for a week. He can instruct whoever is going to do it how to go about it (e.g., the blood should be chilled, but not frozen).
Second, please write, and have your main doctor write, an email to Dr. Druey informing him of what happened. You can also request and authorize the hospital to send a copy of your hospital records to Dr. Druey directly.
I wish you a speedy and complete recovery!