NF-KB plays various roles in the differentiation and regulation of different CD4+ T cell subsets. The document discusses the role of NF-KB in the development of TH1 and TH2 cells, natural regulatory T cells in the thymus, Treg suppression of the immune response, and the development of TH-17 and Th9 cells. The author also mentions the roles of NF-KB in follicular helper T cells.