Changes in the Serum Levels of Interleukin-17/Interleukin-23 During Acute Rejection in Liver Transplantation

Interleukin-23 (IL-23) and T helper 17 (Th17) cells have been cast as major players in autoimmunity, but their role in transplantation immunity remains to be specified. The aim of our study was to investigate the time course of serum levels of IL-23 and IL-17 during hepatic allograft rejection. Serum levels of IL-23 and IL-17 were determined in 20 healthy subjects and 50 hepatic transplant recipients. These patients were divided into 2 groups: group I was composed of 15 patients with acute rejection, and group II was composed of 35 patients without acute rejection. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy. The concentrations of IL-23 were similar for the rejection group and nonrejection group at early postoperative times. We observed a significant increase in serum IL-23 levels in the rejection group when a diagnosis of acute rejection had been established. Similarly to IL-23, at the diagnosis of acute rejection, the concentration of IL-17 was significantly higher in the rejection group versus the nonrejection group. The whole transplant group, including those with stable graft function, had higher serum levels of IL-23 and IL-17 than the controls during the entire postoperative period. In conclusion, IL-23 and IL-17 are up-regulated during acute hepatic rejection. These findings suggest a role for Th17 cells in human liver allograft rejection.