Correlation analysis of the Epstein-Barr virus recruited regulatory T cells in nasopharyngeal carcinoma of immune escape

Abstract

Objective: To investigate the relation of Epstein-Barr virus (EBV)-induced immune escape to regulatory T cells(Treg) in nasopharyngeal carcinoma(NPC). Methods: We recruited 83 patients who were pathologically diagnozed as nasopharyngeal carcinoma and treated in Nanfang Hospital from January to September 2016. CD4(+) CD25(+) FOXP3(+) Treg in peripheral blood was examined by flow cytometry and the level of EBV DNA in the blood was detected by quantitative real-time polymerase chain reaction(qRT-PCR)in 83 patients and 51 healthy adults as control. The expression of FOXP3(+) Treg and EBER in NPC in 32 of 83 patients and in nasopharyngitis in 16 control patients were tested by immunohistochemistry(IHC) and in-situ hybridization(ISH). Results: The ratio of Treg in blood in patients with NPC(5.29±1.45)% was higher than that in control group (4.78±1.19) %, with a statistically significant difference(P=0.035). The ratio of Treg in blood in patients with positive EBV was higher than that in patients with negative EBV(P=0.013), and there was a positive correlation between EBV DNA copies and Treg ratio(r=0.335, P=0.002). The density of FOXP3(+) Treg in NPC was higher than that in nasopharyngitis(P=0.001). Positive correlation was found between the density of FOXP3(+) Treg and the stain intensity of EBER(r=0.496, P=0.004). Conclusion: The ratios of Treg in blood and tissue in NPC patients with positive EBV are significantly increased, indicating a role of Treg in EBV-induced immune escape in NPC.