Jenn, I think you know my story. Allergic to betaseron, too many severe IPIR's on copaxone, infusion/allergic reactions on tysabri and the presence of antibodies. I know this is a tough decision to make. In a way I am glad that I tried tysabri despite the reactions because if I hadn't, I guess I would always be wondering if it was the one treatment that would help. The risk of PML's obviously also has to be considered.