INTERFERON-BETA RESULTS IN IMMEDIATE REDUCTION OF CONTRAST-ENHANCED MRI LESIONS IN MULTIPLE-SCLEROSIS PATIENTS FOLLOWED BY WEEKLY MRI

Interferon beta-1a and -1b reduce the frequency and severity of clinic al exacerbations, and reduce both T-2-weighted and contrast-enhanced M RI activity in patients with multiple sclerosis (MS). Several recent r eports suggest that at the initiation of treatment there may be transi ent worsening of symptoms associated with the induction of interferon gamma-secreting cells. We studied eight MS patients with weekly brain MRI's after starting interferon beta treatment, and found immediate re duction in the number of contrast-enhancing lesions. Several patients did experience recurrence of previous symptoms without concomitant ope ning of the blood brain barrier on contrast-enhanced MRI. These data s uggest that the symptoms described after the initiation of interferon beta are not associated with new disease activity, but rather may be r elated to preexisting lesions. This has implications for both understa nding the immunopathogenesis of the disease and for its treatment.