Interleukin-21: a modulator of lymphoid proliferation, apoptosis and differentiation

Nat Rev Immunol. 2005 Sep;5(9):688-98. doi: 10.1038/nri1688.


The interleukin-21 (IL-21)-IL-21-receptor system was discovered in 2000. It was immediately of great interest because of the homology of IL-21 to IL-2, IL-4 and IL-15, and of the IL-21-receptor subunit IL-21R to the beta-subunit of the IL-2 receptor, and because the IL-21 receptor also contains the common cytokine-receptor gamma-chain, the protein that is mutated in X-linked severe combined immunodeficiency. As we discuss, IL-21 has pleiotropic actions, from augmenting the proliferation of T cells and driving the differentiation of B cells into memory cells and terminally differentiated plasma cells to augmenting the activity of natural killer cells. Moreover, it has antitumour activity and might have a role in the development of autoimmunity, so these findings have implications for the treatment of cancer and autoimmune diseases.

Publication types

  • Research Support, N.I.H., Intramural
  • Review

MeSH terms

  • Animals
  • Apoptosis / immunology*
  • Cell Differentiation / immunology*
  • Humans
  • Interleukins / physiology*
  • Lymphocytes / cytology
  • Lymphocytes / immunology*


  • Interleukins
  • interleukin-21