STAT3 and myeloid sarcoma: In MS patients, there is a signal pathway of IL-10-dependent Treg cell generation: IL-10 activates signal transducer and activator of transcription 3 (STAT3) and converts DCs into tolDCs; in the presence of IL-2, tolDCs further induce STAT5 phosphorylation in naive T cells and promote Treg cell generation (92).