The role of Th22 cells, from tissue repair to cancer progression

CD4+ T helper (Th) cells play a significant role in modulating host defense. In the presence of lineage specific cytokine cocktail, Naive CD4+ T cells can differentiate into several categories with distinct cytokines profile and effector functions. Th22 cells are a recently identified subset of CD4+ T cell, which differentiate from Naive CD4+ T in the presence of IL-6 and TNF-α. Th22 characterized by the production of interleukin-22 (IL-22) and expression of aryl hydrocarbon receptor (AHR). The main function of Th22 cells is to participate in mucosal defense, tissue repair, and wound healing. However, controversial data have shown that overexpression of IL-22 can lead to pathological changes under inflammatory conditions and tumor progression. This review summarizes our knowledge about the role of Th22 and IL-22 cells in tumor progression through induction of inflammation.