The Role of Serum Leptin Levels in Multiple Sclerosis Disease Activity While on Interferon Beta 1a (Rebif) Treatment

Inclusion Criteria: * Confirmed diagnosis of multiple sclerosis per update of McDonald criteria * Initiating treatment with interferon beta 1a subcutaneous injection with minimal dosing of 22mcg. * 18-60 years of age. * Women who are not pregnant or breast feeding, and who do not intend to become pregnant. * Stable dose of concomitant medications for 30 days prior to baseline. Efforts should be made to maintain steady doses of concomitant medications for the duration of the study. Exclusion Criteria: * Treatment on other interferon preparations, glatiramer acetate, in last 30 days or 6 months on Natalizumab, mitoxantrone, cyclosporine or other immunomodulators as determined by the PI. * Treatment with any other investigational treatments within the past year or treatment with any investigational treatments for multiple sclerosis within the last year. * Any progressive form of MS. * Known Hypersensitivity to interferon beta 1a. * Inability to administer subcutaneous injections * Inability to undergo laboratory evaluation. * Seropositivity for HIV (by medical history) * Diabetes Mellitus Tyle I or II (by medical history) * Hepatitis B or C (by medical history) * Uncontrolled psychiatric disorder. * Any unstable illness that the investigator's opinion precludes participation in this study. * Inability to maintain compliance with study protocol. * Implanted devices or metal which would contraindicate MRI. * Clinically significant abnormalities in CBC or CMP * MMSE \<25