The historical T cell dichotomy (TH1 versus TH2) changed by the identification of TH17 and Treg cells. These populations were linked to a wide range of immunological disorders such as immunodeficiencies, inflammatory and allergic diseases. Subsequently, this dualistic view of T cell biology was overcome by the previously unappreciated plasticity of T cells.
Primary bile acids (BA) are liver-derived steroid acids involved in lipid digestion. Then, colonic bacteria yield secondary BA, which are potentially cytotoxic and carcinogenic. Interestingly, BA have emerged as modulators of innate immunity and gut inflammation. Indeed, there is the notion that molecules containing a sterol-like core act as specific lymphocyte transcriptional factor inhibitors.
