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Updated: May 20, 2026

In Vitro and In Vivo Assessment of T, B and Myeloid Cells Suppressive Activity and Humoral Responses from Transplant Recipients
Published on: August 12, 2017
Interleukin-9 in stable liver transplant recipients
E Fábrega1, M López-Hoyos, D San Segundo
1Gastroenterology and Hepatology Unit, Faculty of Medicine, University Hospital Marqués de Valdecilla, Santander, Spain.
Introduction:
Interleukin-9 (IL-9) has recently been described to be involved in the maintenance of a tolerant environment, but there is no evidence of its role in human liver transplantation. The aim of our study was to measure the serum levels of IL-9 in stable liver transplant recipients and examine their influence on immunosuppressant load.
Methods:
Serum IL-9 levels were determined in 34 healthy subjects and 30 stable liver transplant recipients who were free of rejection episodes for at least 8 years. The results were analyzed according to the blood levels of calcineurin inhibitors (CNIs) at the time of the study: 13 patients showed high concentrations of either cyclosporine or tacrolimus (high CNI: cyclosporine > 80 ng/mL or tacrolimus > 5 ng/mL) and another 17 patients showed low CNI levels.
Results:
The concentrations of IL-9 were significantly higher among liver transplant recipients compared with healthy subjects. In addition, patients with low CNI blood levels showed higher serum levels of IL-9, an effect that was greater with tacrolimus, albeit not significantly.
Conclusions:
These preliminary results indicated that increased serum IL-9 concentrations accompanied a lower immunosuppressive load. It remains to be established whether this relates to induction of tolerance in liver transplantation.

