RAG1 and myeloid sarcoma: Here, we evaluate that (1) TLR4−/− CD4+ naïve T cells inhibit their differentiation into Th17; (2) transfer of TLR4−/− CD4+ naïve T cells into Rag1−/− mice is defective in promoting EAE, a model of MS; and (3) TLR4-RelA-miR-30a signal pathway regulates Th17 differentiation via direct binding of RelA to the silencing element of miR-30a, an inhibitor for Th17 differentiation we previously proved.