Serum levels of interleukin-9 during acute rejection in liver transplantation.

Introduction: Interleukin-9 (IL-9) has been cast as a player in autoimmunity, but its role in liver transplantation remains to be clarified. The aim of our study was to investigate the time course of IL-9 serum levels during hepatic allograft rejection.

Methods: IL-9 serum levels were determined in 34 healthy subjects and 50 hepatic transplant recipients. The patients were divided into two groups: group I was composed of 15 patients with acute rejection episodes, and group II, 35 patients free of this problem. Samples were collected on days 1 and 7 after liver transplantation and on the day of liver biopsy.

Results: The concentrations of IL-9 were similar in the rejection and nonrejection groups over the entire postoperative period. The whole transplant group, including those with stable graft function, showed higher IL-9 serum levels than the controls at all times after liver transplantation.

Conclusions: These preliminary results suggest a lack of participation of IL-9 in human liver allograft rejection.