TH17 Cells in Health and Disease

"About 25 years ago, Mosmann & Coffman introduced the TH1/TH2 paradigm of T helper cell differentiationo which helped explain many aspects of adaptive immunity from eliminating intracellular versus extracellular pathogens to induction of different types of tissue inflammation. However, TH1/TH2 paradigm could not adequately explain development of certain inflammatory responses which provided impetus for the discovery of a new subset ot T cells, called TH17 cells. After the discovery of differentiation and transcription factors for TH17 cells, it was clear that TH17 cells represent an independent subset of T cells with specific functions in eliminating certain extracellular pathogens, presumably not adequately handled by TH1 or TH2 cells. The major role of TH17 cells has been described in inducing auto-immune inflammation. The discovery of TH17 cells has expanded the TH1/TH2 paradigm, and the integration of TH17 cells with TH1 and TH2 effector cells is beginning to explain the underlying mechanisms of tissue inflammation in a number of infections and auto-immune disease settings--From Chapter one by Vijay Kuchroo"--Cover, p. [4]