Distinct chemokine receptor and cytokine expression profile in secondary progressive MS

Background: Chemokines, small chemotactic cytokines, have been implicated i n active relapsing-remitting MS (RRMS). However, the role of chemokines and chemokine receptors has not been specifically studied in secondary progres sive MS (SPMS). Methods: Fifteen patients with SPMS, 15 patients with relap ses of RRMS, 10 patients with RRMS in remission, and 20 healthy controls we re included in this study. The expression of CC chemokine receptor 1(CCR1), CCR2, CCR3, CCR5, and CXC chemokine receptor 3(CXCR3) was studied on leuko cyte subsets using flow cytometry, and the cytokine profile of T cells expr essing CCR2 and CCR5 was determined. The authors also studied the effect of treatment with interferon-beta -1b on the expression of chemokine receptor s in SPMS. Results: The authors found a significantly higher percentage of CCR2-expressing T cells in SPMS than in the other patients groups. CCR2-pos itive T cells produced high levels of interleukin (IL)-5 and low levels of tumor necrosis factor alpha, indicating a T-helper type 2 (Th2)/T-cytotoxic type 2 (Tc2) profile of these cells. The expression of CCR5, a chemokine r eceptor associated with Th1 responses, was significantly lower in SPMS than in patients with active RRMS. Interferon (IFN) beta -1b treatment in SPMS did not alter chemokine receptor expression in SPMS. Conclusion: The author s find qualitative differences in the systemic inflammatory response in RRM S and SPMS, indicating a distinct inflammatory environment in SPMS. Chemoki ne receptor expression in SPMS did not change after treatment with IFN beta -1b. It remains to be established if these findings reflect differences be tween RRMS and SPMS in effector or regulatory mechanisms.