I've tested positive to antibodies twice now and I've been on the Tysabri since last October. I'm really scared now. I don't have any idea what to do. My neuro told me that there is a lot of controversy whether to keep people on it (if they aren't having attacks, etc). I've not had any attacks but I have no idea if there is damage going on in the brain. My neuro is going to keep me on it and see. I wonder if anyone has any information on this?