There is a theory out there that all autoimmune diseases stem from Epstein Barr.

No one knows the cause of MS. It is common for those with one autoimmune disease to get another. MS is actually considered an immune-mediated disease. No antigen has been found, so it can't be considered auto-immune. http://www.nationalmssociety.org/What-is-MS/Def...

Has not yet been proven. I believe it though

Doesn't seem to although you may have another autoimmune problem. Very common among MS'ers.

Like IggysMom said, we don't know the cause. But it is possible to have more than one autoimmune (or immune mediated) disease.In my family, all my doctors were fascinated that I had MS, my mom has Grave's Disease, and her dad (my grandpa) had Parkinson's. No one knew what to make of it, but all our docs thought there was some connection. Good luck!