Homeostatic (IL-7) and effector (IL-17) cytokines as distinct but complementary target for an optimal therapeutic strategy in inflammatory bowel disease

Curr Opin Gastroenterol. 2009 Jul;25(4):306-13. doi: 10.1097/MOG.0b013e32832bc627.


Purpose of review: This review focuses on CD4+ T cells involved in the mediation of inflammatory tissue damage in murine models of inflammatory bowel diseases (IBDs). In particular, we describe the distinct roles of the homeostatic cytokine IL-7, which is essential to the maintenance of colitogenic memory CD4+ cells, and the newly discovered effector cytokine IL-17. We also discuss the close correlation between colitogenic Th17-type CD4+ T cells and inducible CD4+CD25+Foxp3+ regulatory T cells.

Recent findings: IBDs are characterized by wasting and chronic intestinal inflammation induced by many different cytokine-mediated pathways. It is clearly recognized that medical and surgical interventions do not cure Crohn's disease because relapse is the rule after remission. Until a few years ago, IBD was classified into Th1-dependent, that is, Crohn's disease, and Th2-dependent, that is, ulcerative colitis, phenotypes. However, in recent years, it has been shown that new T-cell subclasses, that is, Th17 and regulatory T cells (T(R)), exist independently of Th1 and Th2 and that they play a central role in modulating IBD.

Summary: The persistence of IL-7-dependent colitogenic memory CD4+ T cells is critical to the maintenance of experimental colitis. On the other hand, though Th1 and Th2 colitogenic memory CD4+ cells exist, in recent years the central role of IL-17-producing Th17-type cells in IBD has attracted renewed interest. The development of molecularly targeted therapies aimed at a variety of different Th-dependent pathogenic mechanisms may represent a novel approach to IBD therapy.

Publication types

  • Review

MeSH terms

  • Animals
  • Cohort Studies
  • Cytokines / drug effects
  • Cytokines / metabolism
  • Disease Models, Animal
  • Drug Delivery Systems
  • Homeostasis / immunology
  • Immunologic Memory / immunology
  • Immunosuppressive Agents / pharmacology*
  • Inflammatory Bowel Diseases / drug therapy*
  • Inflammatory Bowel Diseases / immunology*
  • Interleukin-17 / immunology
  • Interleukin-17 / metabolism*
  • Interleukin-7 / immunology
  • Interleukin-7 / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Mice, SCID
  • Sensitivity and Specificity
  • T-Lymphocytes, Helper-Inducer / drug effects
  • T-Lymphocytes, Helper-Inducer / immunology*
  • T-Lymphocytes, Regulatory / drug effects
  • T-Lymphocytes, Regulatory / metabolism


  • Cytokines
  • Immunosuppressive Agents
  • Interleukin-17
  • Interleukin-7