Department of Pathology, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
J Clin Exp Hematop. 2024 Sep 28;64(3):183-190. doi: 10.3960/jslrt.24019. Epub 2024 Jul 31.
Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare condition characterized by benign localized lymphadenopathy and clinical symptoms such as fever, sore throat, odynophagia, and leukopenia. Though the etiology of KFD is unknown, this condition is similar to viral infection, including increased infiltration of activated plasmacytoid dendritic cells. KFD exhibits three histological phases that reflect its progression status: proliferative, necrotic, and xanthomatous lesions. The expression loss of pan T-cell markers, such as CD2, CD5, and CD7, of infiltrating T-cells is observed in KFD cases, complicating the distinction from T-cell lymphoma. However, reports on the loss of their expression in KFD have been limited. Furthermore, the precise population of the T-cell subset in KFD is still unclear. Here, we focused on surface markers and transcription factors for T-cell differentiation and analyzed them immunohistochemically in 46 KFD cases. We observed diminished CD5 expression of CD8-positive (CD5 CD8+) T-cells in the proliferative lesion of KFD cases. Furthermore, these CD5 CD8+ T-cells expressed T-BET, a master regulator of type 1 helper T-cells. The upregulation of T-BET and downregulation of CD5 in CD8+ T-cells causes dysregulated activation and proliferation of CD8+ T-cells, potentially contributing to the unique histopathological features of KFD. Recognizing the frequent infiltration of T-BET-positive CD5 CD8+ T-cells in KFD is important for distinguishing it from mature T-cell lymphoma. Our findings suggest that the immune response in KFD shares similarities with viral infections and highlight the importance of characterizing T-BET-positive CD5 CD8+ T-cell populations for understanding KFD pathogenesis.
菊池-藤本病（Kikuchi-Fujimoto disease，KFD），又称组织细胞坏死性淋巴结炎，是一种罕见疾病，以良性局限性淋巴结病和发热、咽痛、吞咽困难和白细胞减少等临床症状为特征。虽然 KFD 的病因不明，但这种疾病类似于病毒感染，包括活化浆细胞样树突状细胞的浸润增加。KFD 表现为三个组织学阶段，反映其进展状态：增生、坏死和黄瘤病变。浸润 T 细胞中 pan T 细胞标志物（如 CD2、CD5 和 CD7）的表达缺失在 KFD 病例中观察到，这使得与 T 细胞淋巴瘤的鉴别变得复杂。然而，关于 KFD 中其表达缺失的报道有限。此外，KFD 中 T 细胞亚群的确切群体仍不清楚。在这里，我们专注于 T 细胞分化的表面标志物和转录因子，并在 46 例 KFD 病例中进行免疫组织化学分析。我们观察到 KFD 病例增生病变中 CD5 CD8+T 细胞的 CD5 表达减少。此外，这些 CD5 CD8+T 细胞表达 T-BET，这是 1 型辅助 T 细胞的主要调节因子。CD8+T 细胞中 T-BET 的上调和 CD5 的下调导致 CD8+T 细胞的失调激活和增殖，这可能导致 KFD 独特的组织病理学特征。认识到 KFD 中 T-BET 阳性 CD5 CD8+T 细胞的频繁浸润对于将其与成熟 T 细胞淋巴瘤区分开来很重要。我们的研究结果表明，KFD 中的免疫反应与病毒感染相似，并强调了表征 T-BET 阳性 CD5 CD8+T 细胞群体对于理解 KFD 发病机制的重要性。
