CD4 and myeloid sarcoma: To understand the effects of LLL12b in regulating Teff:Treg balance in an inflammatory environment such as MS lesions, we show that LLL12b shifts the balance of RORγt:Foxp3 in CD4+ T cells toward Foxp3 (Figure 3), suggesting that STAT3 inhibition with LLL12b regulates the fate decision of Th17 and Tregs.