Migratory behavior of lymphocytes isolated from multiple sclerosis patients: Effects of interferon β‐1b therapy

Previous reports by our group and by others have shown that in vitro treatment of T cells derived from healthy, normal subjects with interferon β-1b (IFN-β1b) reduces metalloproteinase (metalloproteinase type 9 [MMP-9]) activity with a consequent reduction in lymphocyte migration. In this study, we used a Boyden chamber assay to assess the migratory capacity of T cells derived from multiple sclerosis patients who either did or did not receive IFN-β1b. Lymphocytes derived from patients treated for less than 2 years with IFN-β migrated at a low rate that was indistinguishable from that of cells isolated from healthy donors. However, longer term treatment with IFN (>3.5 years) was associated with a reversion of the migration to a high level that did not differ statistically from that of cells isolated from untreated multiple sclerosis patients. For both high-migratory groups, migration could be reduced to control levels after the exogenous addition of TIMP-1, a relatively specific inhibitor of the MMP-9, implicating this protease in the process of T-cell migration. Our findings suggest that one of the mechanisms by which IFN-β exerts its action is by reducing MMP-9 activity and thus the entry of inflammatory cells into the nervous system and, as such, MMPs may constitute potential therapeutic targets in inflammatory diseases such as multiple sclerosis.