Therapeutic targeting of Janus kinases

Immunol Rev. 2008 Jun:223:132-42. doi: 10.1111/j.1600-065X.2008.00644.x.


Cytokines play pivotal roles in immunity and inflammation, and targeting cytokines and their receptors is an effective means of treating such disorders. Type I and II cytokine receptors associate with Janus family kinases (JAKs) to effect intracellular signaling. These structurally unique protein kinases play essential and specific roles in immune cell development and function. One JAK, JAK3, has particularly selective functions. Mutations of this kinase underlie severe combined immunodeficiency, indicative of its critical role in the development and function of lymphocytes. Because JAK3 appears not to have functions outside of hematopoietic cells, this kinase has been viewed as an excellent therapeutic target for the development of a new class of immunosuppressive drugs. In fact, several companies are developing JAK3 inhibitors, and Phase II studies are underway. Mutations of Tyk2 cause autosomal recessive hyperIgE syndrome, and in principle, Tyk2 inhibitors might also be useful as immunosuppressive drugs. JAK2 gain-of-function mutations (V617F) underlie a subset of disorders collectively referred to as myeloproliferative diseases and phase 2 trials using JAK inhibitors are underway in this setting. Thus, we are learning a great deal about the feasibility and effectiveness of targeting Janus kinases, and it appears likely that this will be a fruitful strategy in a variety of settings.

Publication types

  • Review

MeSH terms

  • Animals
  • Autoimmune Diseases / drug therapy
  • Autoimmune Diseases / enzymology
  • Autoimmune Diseases / immunology
  • Clinical Trials as Topic
  • Graft Rejection / drug therapy
  • Graft Rejection / enzymology
  • Graft Rejection / immunology
  • Humans
  • Immunosuppression Therapy
  • Janus Kinases / antagonists & inhibitors*
  • Janus Kinases / chemistry
  • Janus Kinases / genetics
  • Janus Kinases / immunology*
  • Job Syndrome / drug therapy
  • Job Syndrome / enzymology
  • Job Syndrome / immunology
  • Leukemia / drug therapy
  • Leukemia / enzymology
  • Leukemia / pathology
  • Mice
  • Mutation
  • Protein Kinase Inhibitors / administration & dosage*
  • Protein Kinase Inhibitors / adverse effects
  • Protein Kinase Inhibitors / immunology
  • Signal Transduction*
  • TYK2 Kinase / antagonists & inhibitors
  • TYK2 Kinase / genetics
  • TYK2 Kinase / immunology*
  • src Homology Domains / drug effects


  • Protein Kinase Inhibitors
  • Janus Kinases
  • TYK2 Kinase