The University of Tokyo, Tokyo, Japan.
Yamaguchi University, Yamaguchi, Japan.
Vet Pathol. 2022 Sep;59(5):733-739. doi: 10.1177/03009858221102599. Epub 2022 Jun 8.
T-zone lymphoma (TZL) is an indolent, nodal lymphoma that has been clinically characterized in detail in dogs, and T-zone hyperplasia (TZH) is a hyperplastic change in lymph nodes associated with antigen processing. In some cases, histopathological features of TZL and TZH are similar, and are difficult to differentiate by morphology alone. Since there have been few publications characterizing their immunohistochemical profiles, histological, immunohistochemical, and clonality examinations were performed using formalin-fixed paraffin-embedded samples of canine lymph nodes with TZL (14 cases) and canine lymph nodes with TZH associated with nonlymphocytic tumors (10 cases). Immunohistochemically, small- to medium-sized lymphocytes of TZL were immunopositive for CD3, CD5, and HLA-DR, and negative for CD45, FOXP3, and granzyme B (GRB) in all cases. Among these 14 cases, 11 were immunopositive for CD8 and 1 was CD20 positive. Paracortical lymphocytes in TZH were diffusely immunopositive for CD3, CD5, and CD45, with scattered immunopositivity for CD8, HLA-DR, FOXP3, and GRB, and negative for CD20 in all cases. A clonal TCR gene rearrangement was detected in 13/14 TZL and none of the TZH cases. The present study revealed that TZL is a clonal proliferation of monomorphic CD8CD45GRB T cells, while TZH consists of an immunophenotypically heterogenous population of CD45 T cells that are variably positive for CD8 and FOXP3. These results suggest that canine TZL is a clonal proliferation of naïve or premature cytotoxic T cells. Regarding TZH, variable immunopositivity for cytotoxic and regulatory T-cell antigens may reflect immune responses to a variety of regional neoplastic lesions.
T 区淋巴瘤（TZL）是一种惰性的结内淋巴瘤，在犬中已得到详细的临床描述，T 区增生（TZH）是与抗原处理相关的淋巴结增生性改变。在某些情况下，TZL 和 TZH 的组织病理学特征相似，仅通过形态学难以区分。由于对其免疫组织化学特征的报道较少，因此对犬 TZL（14 例）和与非淋巴细胞肿瘤相关的犬 TZH（10 例）的福尔马林固定石蜡包埋样本进行了组织学、免疫组织化学和克隆性检查。免疫组织化学染色显示，TZL 的中小淋巴细胞均为 CD3、CD5 和 HLA-DR 阳性，而 CD45、FOXP3 和颗粒酶 B（GRB）均为阴性。在这 14 例中，有 11 例 CD8 阳性，1 例 CD20 阳性。TZH 的副皮质淋巴细胞弥漫性表达 CD3、CD5 和 CD45，散在表达 CD8、HLA-DR、FOXP3 和 GRB，所有病例均为 CD20 阴性。在 13/14 例 TZL 中检测到 TCR 基因克隆性重排，而在 TZH 中均未检测到。本研究表明，TZL 是单形性 CD8CD45GRB T 细胞的克隆性增殖，而 TZH 由一群表型异质性的 CD45 T 细胞组成，这些细胞对 CD8 和 FOXP3 的表达呈不同程度的阳性。这些结果提示犬 TZL 是幼稚或早期细胞毒性 T 细胞的克隆性增殖。关于 TZH，细胞毒性和调节性 T 细胞抗原的可变免疫阳性可能反映了对各种局部肿瘤病变的免疫反应。
