Features and roles of T helper 22 cells in immunological diseases and malignancies.

T helper 22 (Th22) cell populations are a newly identified subset of CD4+  T cells that primarily mediate biological effects on the epithelial barrier through interleukin (IL)-22. Although, new studies showed that both Th22 and IL-22 are closely associated with the pathogenesis of inflammatory, autoimmune and allergic disease as well as malignancies. In this review, we aim to describe the development and characteristics of Th22 cells as well as their roles in the immunopathogenesis of immune-related disorders and cancer.