The role of IL-21 in immunity and cancer

Interleukin-21 (IL-21), produced predominantly by CD4+ T cells and natural killer T (NKT) cells, is a newly discovered member of the common γ-chain family of cytokines. It has been implicated in many immunological processes and has been linked to autoimmune diseases, allergies and other inflammatory diseases. In recent years, the role for IL-21 in the pathogenesis of cancer has also been extensively studied. In this review, we will discuss recent advances concerning the role of IL-21 in immunological processes and the pathogenesis of cancer.