Zhifan Zhao, Zhuojun Liu, Qiang Huang, Zhipeng Zhou, Mengjia Li, Meng Lv, Yuqian Sun, Xiaodong Mo, Lanping Xu, Yu Wang, Xiaohui Zhang, Liang Chen, Xiangyu Zhao, Zhilei Bian, Xiaojun Huang, Xuying Pei
These findings suggest that T-cell EBV quantification distinguishes a therapeutically challenging subtype of EBV reactivation characterized by immune dysfunction and reduced responsiveness to rituximab-based therapy. Incorporating assessment of cellular viral reservoirs into post-transplant EBV monitoring strategies may facilitate early risk stratification and support timely therapeutic escalation beyond rituximab alone.
OBJECTIVES: EBV reactivation after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is typically monitored by plasma viral load, but this fails to capture cellular reservoirs. Lineage-specific testing, though usually performed in high-risk patients, may identify biologically distinct disease states. We aimed to evaluate the clinical and biological significance of lineage-specific EBV quantification especially ectopic EBV infection in T cells in allo-HSCT recipients with EBV reactivation.
METHODS: We analyzed 144 allo-HSCT recipients with EBV reactivation who underwent lineage-specific EBV quantification, assessed whether T-cell tropic EBV burden identifies a phenotype with reduced responsiveness to rituximabtherapy, an increased risk of post-transplant lymphoproliferative disorder (PTLD), and specific features of underlying immune dysfunction.
RESULTS: Among the tested high-risk patients with high EBV loads and clinical symptoms, 66.6% exhibited T-cell tropic EBV infection. Compared with non-T-cell tropic infection, T-cell tropism was associated with higher rituximab courses and lower complete response rates (67% vs. 81%, P=0.029), suggesting insufficient efficacy of CD20-directed therapy. Patients with T-cell tropic infection had a significantly higher 1-year cumulative incidence of PTLD compared to the non-T-cell tropic group(77% vs. 41.6%; P < 0.001). Single-cell RNA sequencing and mass cytometry analyses revealed an exhausted T-cell phenotype with diminished stemness in T-cell tropic EBV infected patients.
CONCLUSIONS: These findings suggest that T-cell EBV quantification distinguishes a therapeutically challenging subtype of EBV reactivation characterized by immune dysfunction and reduced responsiveness to rituximab-based therapy. Incorporating assessment of cellular viral reservoirs into post-transplant EBV monitoring strategies may facilitate early risk stratification and support timely therapeutic escalation beyond rituximab alone.