IL-2-producing T(FH) cells sustain T(reg) cell homeostasis and immune tolerance in the gut.

IL-2-producing T(FH) cells are essential for maintaining T(reg) cell homeostasis and preventing colitis in the gut-associated lymphoid tissues of mice.

• Why it matters: Understanding how immune tolerance is maintained in the gut is crucial because its disruption leads to inflammatory diseases like colitis. The role of T(FH) cells in this process was previously unclear, especially beyond their known support for B cells.
• What they did: The study used mouse models to show that T(FH) cells produce IL-2 at specific gut sites, which is necessary for GALT T(reg) cell stability and controlling effector T cell expansion, with IL-2-deficient T(FH) cells causing colitis.
• The result: Loss of IL-2-producing T(FH) cells results in colitis and multiorgan inflammation, which can be alleviated by antibiotics, highlighting a novel immunoregulatory function of T(FH) cells in gut tolerance.