Correlation between GITR gene methylation and immune rejection in liver transplantation

Objective By observing the change of DNA methylation modification after liver transplantation, to elucidate if DNA methylation status of GITR is associated with response to immune reaction after liver transplantation. Method The peripheral blood (PB) of 95 patients with immune reaction after liver transplantation was collected. DNA methylation of GITR was carried out by Sequenom MassARRAY EpiTYPING, and the expression of GITR in T cells was evaluated by flow cytometry. Result The positive expression rate of GITR before and after the immune reaction was 6.89% and 22.14% separately (P<0.05). Moreover, average DNA methylation level of CpGs in GITR before immune reaction was 88%, whereas hypomethylation happened after immune reaction with 82%. DNA methylation also revealed significant difference (P<0.05) between before and after immune reaction. There was a close negative correlation between low levels of the methylation of GITR and the protein expression rate after immunological rejection (r=-0.88, P<0.05). Conclusion Hypomethylation happened after immune reaction in liver transplantation patients, which may hint that the decreased DNA methylation of CpGs in GITR might be related to the occurrence and development of the immune reaction. Key words: Liver transplantation; Immune rejection; GITR gene; Methylation