Early CD4 + T cell immune reconstitution as a biomarker for Epstein-Barr virus control following allogeneic transplantation.

PURPOSE: Achieving high-quality immune reconstitution (IR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is directly associated with the patient's ability to resist infections, prevent tumor relapses, and suppress graft-versus-host disease (GVHD). The status of CD4 + T cells is critical for reconstituting adaptive immunity after transplantation; however, the patterns of reconstitution and their influencing factors remain unclear. METHODS: This retrospective cohort study involved 164 patients who underwent myeloablative allo-HSCT from April 2016 to May 2023. Based on the early post-transplantation CD4 + T cell counts, the cohort was divided into two groups: 73 patients with high-quality IR (HIR) and 34 patients with low-quality IR (LIR). LIR was associated with an increased risk of Epstein-Barr virus (EBV) reactivation following transplantation. Plasma EBV viral load was monitored weekly using quantitative PCR for the first 100 days post-transplantation. RESULTS: The LIR group had a higher viral load at the time of the first EBV reactivation and a significantly earlier first reactivation compared to the HIR group. No significant differences were observed in overall survival, GVHD incidence, or relapse rates between the groups. A CD4 + T cell count of < 60 cells/μL within 30 days post-transplantation was associated with a higher incidence of EBV viremia compared to the control group. CONCLUSION: These findings suggest that early CD4 + T cell counts may serve as a predictive marker for post-transplant EBV infection.