Interferon-β1a reduces plasma CD31+ endothelial microparticles (CD31+EMP) in multiple sclerosis

Background: A correlation between plasma CD31+ endothelial microparticles ( CD31+ EMP) levels and clinical, as well as brain MRI activity, in multiple sclerosis ( MS) patients has been previously reported. However, the effect(s) of treatment with interferon-beta 1a (IFN-beta 1a) on plasma levels of CD31+ EMP has not been assessed. In a prospective study, we measured plasma CD31+ EMP levels in 30 patients with relapsing-remitting MS. Methods: Using flow cytometry, in a blinded study, we measured plasma CD31+ EMP in 30 consecutive patients with relapsing-remitting MS (RRMS) prior to and 4, 12, 24 and 52 weeks after initiation of intramuscular therapy with interferon-beta 1a (IFN-beta 1a), 30 micrograms weekly. At each visit, clinical examination was performed and expanded disability status scale (EDSS) scores were assessed. Results: Plasma levels of CD31+ EMP were significantly reduced from 24 through 52 weeks following initiation of treatment with IFN-beta 1a. Conclusion: Our data suggest that serial measurement of plasma CD31+ EMP levels may be used as a surrogate marker of response to therapy with INF-beta 1a. In addition, the decline in plasma levels of CD31+ EMP further supports the concept that IFN-beta 1a exerts stabilizing effect on the cerebral endothelial cells in pathogenesis of MS.