CD4 and myeloid sarcoma: Exosomes secreted by human MSCs [stimulated by interferon gamma (IFN-γ)] can alleviate demyelination in MS mice, decrease the levels of proinflammatory Th1 and Th17 cytokines (including IL-6, IL-12p70, IL-17AF, and IL-22), increase the levels of immunosuppressive cytokines, and upregulate CD4+CD25+FOXP3+ regulatory T cells in the spinal cord of MS mice.