Effect of steroids on Gd-enhancing lesions before and during recombinant beta interferon 1a treatment in relapsing remitting multiple sclerosis.

The aim of this study was to investigate whether a concomitant treatment with recombinant interferon beta 1a (rIFN beta-1a) modifies the effect of steroids on the blood-brain barrier (BBB) in relapsing remitting MS patients, as evaluated by enhanced MRI of the brain. We evaluated 19 patients with a clinical relapse treated only with intravenous methylprednisolone (IVMP; 1 g daily for 6 days), and 10 patients who experienced a clinical relapse and were treated with IVMP (1 g daily for 6 days) during an rIFN beta-1a treatment period. The number and volume of enhancing lesions were analyzed on four serial MR images obtained at monthly intervals (one scan before and three scans after IVMP treatment). A significant reduction in the mean number and volume of enhancing lesions was seen in the first scan after IVMP treatment in all patients. However, while persistently low enhancement was seen in the follow-up scans of patients treated with rIFN beta-1a, a rebound effect (i.e., increase in the number and volume of gadolinium-enhancing lesions) was observed in the other patients during the follow-up. These data suggest that rIFN beta-1a prolongs the beneficial effect of steroids on the BBB.