Department of Pathology, The University of Hong Kong, Hong Kong.
School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong.
Viruses. 2023 Feb 2;15(2):423. doi: 10.3390/v15020423.
Epstein-Barr virus (EBV) latency patterns are well defined in EBV-associated epithelial, NK/T-cell, and B-cell malignancies, with links between latency stage and tumorigenesis deciphered in various studies. studies suggest that the oncogenic activity of EBV in T-cells might be somewhat different from that in EBV-tropic B lymphoid cells, prompting us to study this much less investigated viral gene expression pattern and its regulation in nine EBV+ peripheral T-cell lymphoma (PTCL) biopsies. Using frozen specimens, RT-PCR showed 6/7 cases with a latency II pattern of EBV gene expression. Analyses of EBNA1 promoter usage and CpG methylation status in these six cases showed that only Qp was used, while Cp, Wp, and Fp were all silent. However, the remaining case showed an exceptionally unique latency III type with lytic activation, as evidenced by EBV lytic clonality and confirmed by the full usage of Cp and Qp as well as weakly lytic Fp and Wp, fully unmethylated Cp and marginally unmethylated Wp. Further immunostaining of the eight cases revealed a few focally clustered LMP1+ cells in 7/8 cases, with rare isolated LMP1+ cells detected in another case. Double immunostaining confirmed that the LMP1+ cells were of the T-cell phenotype (CD3+). In 6/8 cases, sporadically scattered Zta+ cells were detected. Double staining of EBER-ISH with T-cell (CD45RO/UCHL1) or B-cell (CD20) markers confirmed that the vast majority of EBER+ cells were of the T-cell phenotype. Predominant type-A EBV variant and LMP1 30-bp deletion variant were present, with both F and f variants detected. In summary, the EBV gene expression pattern in PTCL was found to be mainly of latency II (BART+EBNA1(Qp)+LMP1+LMP2A+BZLF1+), similar to that previously reported in EBV-infected nasopharyngeal epithelial, NK/T-cell, and Hodgkin malignancies; however, fully lytic infection could also be detected in occasional cases. Rare cells with sporadic immediate-early gene expression were commonly detected in PTCL. These findings have implications for the future development of EBV-targeting therapeutics for this cancer.
EBV（Epstein-Barr virus，爱泼斯坦-巴尔病毒）潜伏模式在 EBV 相关的上皮细胞、NK/T 细胞和 B 细胞恶性肿瘤中得到了很好的定义，并且在各种研究中已经阐明了潜伏阶段与肿瘤发生之间的联系。研究表明，EBV 在 T 细胞中的致癌活性可能与 EBV 嗜性 B 淋巴样细胞中的有些不同，这促使我们研究 EBV 基因表达模式及其在 9 例 EBV+外周 T 细胞淋巴瘤（PTCL）活检中的调控，这些研究以往涉及较少。使用冷冻标本，RT-PCR 显示 7 例中的 6 例具有 EBV 基因表达的潜伏 II 模式。对这 6 例中 EBNA1 启动子使用和 CpG 甲基化状态的分析表明，仅使用了 Qp，而 Cp、Wp 和 Fp 均处于沉默状态。然而，另一个病例表现出异常独特的潜伏 III 型，伴有裂解激活，这可以通过 EBV 裂解克隆性得到证实，并通过 Cp 和 Qp 的完全使用以及弱裂解 Fp 和 Wp 的完全非甲基化和 Wp 的轻微非甲基化得到证实。对这 8 例的进一步免疫染色显示，在 7/8 例中存在少数局灶性聚集的 LMP1+细胞，在另一个病例中检测到罕见的孤立 LMP1+细胞。双重免疫染色证实 LMP1+细胞为 T 细胞表型（CD3+）。在 6/8 例中，偶尔检测到散在的 Zta+细胞。EBER-ISH 与 T 细胞（CD45RO/UCHL1）或 B 细胞（CD20）标志物的双重染色证实，绝大多数 EBER+细胞为 T 细胞表型。存在主要的 A 型 EBV 变体和 LMP1 30-bp 缺失变体，均检测到 F 和 f 变体。总之，PTCL 中的 EBV 基因表达模式主要为潜伏 II（BART+EBNA1（Qp）+LMP1+LMP2A+BZLF1+），与先前报道的 EBV 感染的鼻咽上皮细胞、NK/T 细胞和霍奇金恶性肿瘤中的表达模式相似；然而，偶尔也可检测到完全裂解感染。在 PTCL 中通常检测到罕见的散发性早期基因表达的细胞。这些发现对未来开发针对这种癌症的 EBV 靶向治疗具有重要意义。
