Reciprocal Th1 and Th17 regulation by mesenchymal stem cells: Implication for multiple sclerosis

Abstract Human mesenchymal stem cells (hMSCs) are being considered for clinical trials of multiple sclerosis (MS). We examined the effects of adult bone marrow‐derived hMSCs on responses of primary human Th1, Th17, and Th1/17 double‐expressing T‐cell subsets, all implicated in MS. As expected, soluble products from hMSCs inhibited Th1 responses; however, Th17 responses were increased. Secretion of interleukin (IL)‐10, considered anti‐inflammatory, was decreased. Pretreating hMSCs with the proinflammatory cytokine IL‐1β accentuated these effects, and caused decreases in the Th1/17 subset. These findings underscore the importance of further preclinical work and immune‐monitoring to define hMSC effects on disease‐relevant immune responses under variable conditions. ANN NEUROL 2010