EBV-DNA viral load and lymphocyte subsets correlation in pediatric infectious mononucleosis with hepatic injury a retrospective cohort study

Background Infectious mononucleosis is often complicated by hepatic injury, in which Epstein–Barr virus load and immune response may play important roles. Objective To investigate the correlation between EBV-DNA viral load and lymphocyte subsets in patients with IM with hepatic injury. Methods A retrospective cohort study was conducted on children diagnosed with IM from January 2022 to August 2025. Patients were divided into hepatic injury group and non-hepatic injury group. EBV-DNA load, lymphocyte subsets (CD3+, CD4+, CD8+, CD19+, CD16+ CD56+) and liver function indicators were measured and analyzed. Results Among 202 children, the hepatic injury group ( n = 143) showed significantly higher EBV-DNA load ( t = 4.844, P < 0.001), increased CD8+ T cell percentage ( t = 7.235, P < 0.001), decreased CD4+/CD8+ ratio ( t = 9.876, P < 0.001) and reduced NK cell percentage ( t = 4.325, P < 0.001). Liver function tests revealed significantly elevated ALT, AST, GGT and TBil ( t = 15.678, 13.456, 8.923, 7.234, P < 0.001), and decreased ALB ( t = 5.678, P < 0.001) in the hepatic injury group. Correlation analysis showed positive correlation between EBV-DNA load and CD8+ T cell percentage ( P < 0.001), and negative correlation with CD4+/CD8+ ratio ( P < 0.001). Multivariate analysis identified high EBV-DNA load and elevated CD8+ T cell percentage as independent risk factors for hepatic injury (OR = 5.678, 1.456, P < 0.001). Conclusion Elevated EBV-DNA load and an increased CD8+ T cell percentage are independently associated with hepatic injury in pediatric IM. Monitoring these parameters may help in identifying children at higher risk for hepatic involvement, although prospective validation is required.