Immunomodulatory effects of IFN-β1a treatment alone or associated with pentoxifylline in patients with relapsing-remitting multiple sclerosis (RRMS)

Interferon-β1a (IFN-β1a) and pentoxifylline (PTX) are reported to be active in relapsing-remitting multiple sclerosis (RRMS), but the mechanisms are not completely understood. In two groups of RRMS patients, we studied the phenotype of peripheral lymphocytes and the level of several cytokines both in sera and in supernatants of activated peripheral blood mononuclear cells (PBMC) before and after 8 months of therapy with IFN-β1a alone or associated with PTX. Our data indicate that patients with RRMS, treated with IFN-β1a, exhibited a significant increase in CD4+CD25++ T suppressor cells, accompanied by a significant decrease in cytotoxic lymphocytes (CD8+CD28- and natural killer [NK] cells) and IFN-γ production, which could both contribute to an explanation of the previously described beneficial effects of IFN-β treatment in MS. The addition of PTX to IFN-β1a treatment did not modify the immunomodulatory effects obtained with IFN-β1a alone. Future studies are needed to demonstrate which immunologic parameters correlate with the clinical benefit of IFN-β1a treatment. © Mary Ann Liebert, Inc.