Hi Keely
My best advice to you is to find a good neurologist and ask the hard questions. You've got a lot going on and since Tysabri has been approved for both MS and Crohns, you got a drug that can be used to treat both. But with the Lupus thrown in, who knows.
There is not one website that will give you the straight scoop on this drug. You will get some here, some there, some somewhere else. The thread above will give a lot of good information, but since the drug is so new on the market, there is still a lot of research being done.
There is an AAN Conference in April where a lot of research papers are being presented by a some top notch researchers who are testing the waters right now. After that conference, the New England Journal of Medicine will publish what was accepted by the community. What is scientifically acceptable as accurate information.
For now, you can gleen what you can from posts here, ask questions from those who are on the drug, and talk to your neurologist. That's the best route to take.
Good luck and welcome to Neurotalk and the MS Community here!