Intrahepatic T17/T Cells in Homeostasis and Disease-It's All About the Balance.

Both acute and chronic hepatic inflammation likely result from an imbalance in the T1/T2 cell response and can lead to liver fibrosis and end-stage liver disease. More recently, a novel CD4+ T helper cell subset was described, characterized by the production of IL-17 and IL-22. These T17 cells 50were predominantly implicated in host defense against infections and in autoimmune diseases. Interestingly, studies over the last 10 years revealed that the development of T17 cells favors pro-inflammatory responses in almost all tissues and there is a reciprocal relationship between T17 and T cells. The balance between T17and T cells is critical for immune reactions, especially in injured liver tissue and the return to immune homeostasis. The pathogenic contribution of T17 and T cells in autoimmunity, acute infection, and chronic liver injury is diverse and varies among disease etiologies. Understanding the mechanisms underlying T17 cell development, recruitment, and maintenance, along with the suppression of T cells, will inform the development of new therapeutic strategies in liver diseases. Active manipulation of the balance between pathogenic and regulatory processes in the liver may assist in the restoration of homeostasis, especially in hepatic inflammation.