Autoimmune conditions cluster in families with high risk for multiple sclerosis than in general population which suggests that the disease might arise on a background of a generalized susceptibility to autoimmunity. Occurrence of psoriasis, autoimmune thyroiditis, vasculitis, rheumatoid arthritis, scleroderma, lupus are seen more commonly in MS patients. Many of these patients initially get started on beta-IFNs, and usually do not do well on them. According to Investigator's and the USC MS Comprehensive Care Center experience, autoimmune co-morbidity associated with MS can serve as a biological marker predicting good response to GA and unfavorable response to the IFNs.