Epstein-Barr virus gene expression and latent membrane protein 1 gene polymorphism in pediatric liver transplant recipients.

Immunosuppressed pediatric transplant recipients are at risk of developing Epstein-Barr virus (EBV)-associated complications (such as post-transplant lymphoproliferative disorders). Monitoring of the EBV DNA level in blood alone has a low predictive value for the post-transplant course of EBV infection and its complications. Therefore, additional prognostic markers are widely sought. The study aim was to analyze EBV gene expression patterns and LMP1 polymorphism in relation to EBV DNA levels in pediatric liver transplant recipients. EBV load measurement, LMP1 variant, and gene expression analysis were performed in collected prospectively multiple blood samples from 30 patients. Several distinct patterns of EBV gene expression were identified: latency 2 (71%), latency 3 (13%), latency 0 (11%), and lytic infection (5%). In most children's multiple blood samples, both EBV gene expression patterns and expression levels of individual EBV genes varied significantly over time. EBV gene expression patterns were not associated with the EBV load. However, the viral load correlated with the LMP1 and LMP2 expression (r = 0.34; P  = 0.006, and r  = 0.45; P = 0.001, respectively). Two variants of the LMP1 gene were detected, and they were consistent over time in individual patients. A wild type of LMP1 was associated with higher EBV-DNA loads (P = 0.03). This indicates that EBV infection in immunosuppressed patients is a very dynamic process, but changes in the state of EBV infection do not influence significantly the viral load. The latter, however, can be associated with the activity of LMP1 and LMP2 genes, as well as polymorphism of LMP1.