Multiple sclerosis: deficient in vitro responses of blood mononuclear cells to IFN-beta

IFN-beta may modify the clinical course of multiple sclerosis (MS) but is n ot curative, and there are also patients whose disease does not respond to IFN-beta as currently administered. Tests are warranted with a capacity to early discriminate responders from non-responders, thereby altering treatme nt option for the individual patient. In vitro effects of IFN-beta on expre ssion of activation-associated cell surface markers and cytokine production need to be explored in this context. Here we report on the influence in vi tro of IFN-beta on blood mononuclear cells (MNC) prepared from MS patients and healthy controls. MNC were subjected to shortterm culture in the presen ce of IFN-beta at concentrations of 100 U/ml and 1000 U/ml. Expression of c ell surface molecules CD40, CD69, CD80. CD86, CD95 and HLA-DR was measured by flow cytometry. IL-10 and IL-12 p40 production in culture Supernatants w as measured by ELISA. MNC exposed to IFN-beta in vitro enhanced expression of the costimulatory CD80, CD86, the early activation antigen CD69 and the cell death receptor CD95. Expression of CD40 and HLA-DR was not influenced. IFN-beta increased IL-10 but suppressed IL-12 p40 production. In vitro eff ects of IFN-beta on MNC were similar in MS patients and in healthy subjects , except that IFN-beta -induced augmentation of CD86 and CD69 expression wa s less pronounced in MS, in particular in untreated MS patients. Individual MS patients clearly responded differently to IFN-beta in vitro in comparis on with the majority of patients in this cross-sectional study. In conclusi on, anti-inflammatory effects of IFN-beta on blood MNC include augmentation of IL-10 production and suppression of IL-12 p40 production, which are acc ompanied by enhancement of CD69, CD80, CD86 and CD95 expression. The less p ronounced IFN-beta -induced effects on CD86 and CD69 expression in MS vs co ntrols might reflect a defect in immunoregulation in MS. Larger groups shou ld be evaluated, and follow-up studies performed in MS patients before/duri ng IFN-beta treatment in relation to clinical outcome measures to evaluate the usefulness of these markers for possible differentiation between respon ders and non-responders to IFN-beta treatment.