The effect of interferon beta-1b on size of short-lived enhancing lesions in patients with multiple sclerosis

Abstract

Background: Contrast enhancing lesions (CELs) in MRI represent inflammatory events in multiple sclerosis (MS). IFN-β-1b decreases the formation of CELs. However, the ability of IFN-β-1b to reduce the size of CELs arising during therapy has not been extensively investigated. Methods: Thirty patients with relapsing-remitting (RR) MS were followed for a 3-month pre-therapy phase then for a 6-month therapy phase during which treatment with IFN-β-1b at a dosage of 250 μg subcutaneously injected every other day was employed. Each patient underwent monthly clinical and MRI examinations. For all patients, CELs were identified on postcontrast T1-weighted MRIs. CEL number, size, and volume were computed using Medx software. Results: The average number and total lesion volume of CELs visible during the therapy phase were significantly lower than the number and total lesion volume of CELs observed in the pre-therapy phase. However, there was no significant reduction between pre-therapy and therapy phases in the mean size of individual lesions arising during the respective phases. Conclusions: Since size of CELs has been related to severity of tissue damage, the lack of size decrease during therapy suggested a limited therapeutic effect of IFN-β-1b if a blood–brain barrier breakdown has occurred.

Keywords::

• contrast enhancing lesions
• interferon beta 1b
• lesion size
• magnetic resonance imaging
• multiple sclerosis

Acknowledgements

We are sincerely grateful and mostly indebted to all our patients for the time and cooperation required to participate in the study. Ms Devera Schoenberg is acknowledged for editing the manuscript.