TSP-1 promotes the activation of TGF-β1, which is required for the development of Foxp3+ Tregs, which suppress the pro-inflammatory response. TGFβ also limits the activity of NK cells, B cells, Th1 and Th2 cells thereby suppressing the immune response. However, in combination with IL-6, TGF-β1 supports the development of Th17 cells; pro-inflammatory cells that have been shown to play a critical role in the pathogenesis of various autoimmune inflammatory diseases.