Abstract:

Objective Post-transplant lymphoproliferative disorder （PTLD） is a severe complication following liver transplantation， particularly in pediatric patients， with a high incidence rate associated with EpsteinBarr virus （EBV） infection. The immunological microenvironment of PTLD， particularly the cellular and molecular changes associated with EBV infection， remains unclear. Methods Using single-cell RNA sequencing（scRNAseq）， we examined changes in the immune microenvironment of peripheral blood mononuclear cell（PBMC） from pediatric liver transplant recipients across four groups: PTLD patients with EBV infection， EBV-positive non-PTLD transplant recipients， EBV-negative transplant recipients， and healthy children. Results PTLD patients exhibited profound immune dysregulation， marked by weakened cytotoxicity in NK cells， reduced B cell differentiation and activation， and an inflammatory shift in myeloid cells. EBV infection primarily targeted memory B cells and plasma cells in PTLD patients，with uninfected memory B cells showing impaired functional potential. Furthermore， CD8 + T cells in PTLDwere characterized by increased exhaustion and low cytotoxic activity. In addition， regulatory T cells in PTLD displayed enhanced suppressive functions. Conclusion Our findings present an in-depth view of the immune landscape in PTLD，identifying key immune cell alterations associated with EBV infection and PTLD development. These insights could informthe development of targeted therapies aimed at restoring immune function and controlling EBV-driven lymphoproliferation in pediatric liver transplant recipients.

Key words: Post-transplant lymphoproliferative disease ,  , Epstein-Barr virus ,  , Single-cell RNA-sequencing 

摘要：

目的 移植后淋巴增生性疾病（post-transplant lymphoproliferative disorder，PTLD）是肝移植后的严重并发症，与 EB 病毒（Epstein-Barr virus，EBV）感染密切相关，多发于儿科患者中。PTLD 的免疫微环境，特别是 EBV 相关的细胞和分子机制尚不清晰。方法 本研究通过单细胞 RNA 测序（single-cellRNA sequencing，scRNA-seq）技术，分析了以下 4 组小儿肝移植患者外周血单个核细胞（peripheral bloodmononuclear cell，PBMC）的免疫微环境变化 ：EBV 阳性的 PTLD 移植受者、EBV 阳性的非 PTLD 移植受者、EBV 阴性的非 PTLD 移植受者，以及健康儿童。结果 本研究结果显示，PTLD 患者存在显著免疫功能紊乱，表现为 NK 细胞细胞毒性减弱、B 细胞分化及激活障碍、髓系细胞炎症性偏移。EBV 主要感染 PTLD 患者的记忆性 B 细胞及浆细胞，未感染的记忆性 B 细胞功能潜力也显著受损。此外，CD8 + T 细胞呈现出耗竭表型，杀伤活性下降，而调节性 T 细胞的免疫抑制功能增强。结论 本研究揭示了 PTLD 免疫表型的关键变化，为针对性地恢复免疫功能、控制 EBV 相关淋巴增生性疾病提供了理论基础，或有助于优化小儿肝移植后 PTLD 的治疗策略。

关键词: 移植后淋巴增生性疾病 ,  , EB 病毒 , 单细胞测序 , 儿童肝移植