1 Department of Pediatric Hematology and Oncology, University of Giessen, Germany. 2 Department of Pediatric Cardiology, University of Giessen, Germany. 3 Department of Pediatrics, University Hospital of Jena, Germany. 4 Address correspondence to: Stephanie Ruf, M.D., Department of Pediatric Hematology and Oncology, University of Giessen, Germany.
Transplantation. 2014 May 15;97(9):958-64. doi: 10.1097/01.TP.0000438629.13967.16.
Epstein-Barr virus (EBV) is associated with posttransplant lymphoproliferative disease (PTLD), and EBV load measurement is an important tool to monitor transplant patients. Although EBV DNA quantification has high sensitivity to identify patients at risk for PTLD, it lacks specificity. We examined whether EBV gene expression in peripheral B cells can increase specificity or correlates with EBV load.
Altogether, 220 blood samples were collected from pediatric patients after heart transplantation (HTx, n=57), renal transplantation (n=1), or hematopoietic stem cell transplantation (n=21). In each blood sample, EBV load was quantified in whole blood, plasma, and B cells using qPCR. Additionally EBV gene expression (EBNA2, LMP1, LMP2, and BZLF1) in B cells was analyzed using relative quantitative RT-qPCR.
Positive expression of at least one gene was detected in 112 (51%) of 220 samples. Patients with PTLD or chronic high viral loads after solid organ transplantation exhibited no homogeneous EBV gene expression pattern. Expression of LMP2, LMP1, or EBNA2 was only observed when EBV load exceeded 1000 copies/mL. A high correlation between the level of LMP2 expression and EBV load in B cells or whole blood was observed (ρ=0.72 or ρ=0.6, HTx population).
The analysis of EBV gene expression in peripheral B cells does not provide additional information about patients' risk of developing PTLD. As EBV load in whole blood correlates well with LMP2 gene expression in EBV-infected B cells, EBV DNA quantification in whole blood alone seems to be a sufficient tool to monitor these patients.
爱泼斯坦-巴尔病毒（EBV）与移植后淋巴组织增生性疾病（PTLD）有关，EBV 载量测量是监测移植患者的重要工具。虽然 EBV DNA 定量具有很高的灵敏度，可以识别有患 PTLD 风险的患者，但它缺乏特异性。我们研究了外周血 B 细胞中的 EBV 基因表达是否可以提高特异性或与 EBV 载量相关。
共采集了 220 份来自心脏移植（HTx，n=57）、肾移植（n=1）或造血干细胞移植（n=21）后儿科患者的血液样本。在每个血液样本中，使用 qPCR 定量检测全血、血浆和 B 细胞中的 EBV 载量。此外，还使用相对定量 RT-qPCR 分析 B 细胞中的 EBV 基因表达（EBNA2、LMP1、LMP2 和 BZLF1）。
在 220 个样本中，有 112 个（51%）样本检测到至少一种基因的阳性表达。患有 PTLD 或实体器官移植后慢性高病毒载量的患者没有表现出一致的 EBV 基因表达模式。只有当 EBV 载量超过 1000 拷贝/ml 时，才观察到 LMP2、LMP1 或 EBNA2 的表达。在 HTx 人群中，观察到 LMP2 表达水平与 B 细胞或全血中的 EBV 载量高度相关（ρ=0.72 或 ρ=0.6）。
外周血 B 细胞中 EBV 基因表达的分析不能提供关于患者发生 PTLD 风险的额外信息。由于全血中的 EBV 载量与 EBV 感染的 B 细胞中的 LMP2 基因表达高度相关，因此单独检测全血中的 EBV DNA 似乎是监测这些患者的一种足够的工具。
