Non-Hodkin's lymphoma (NHL) is the most frequent hematologic malignancy in humans and dogs. NKG2D is one of the most critical receptors on NK cells, recognizing their natural ligands on malignant cells such as A and B major histocompatibility complex-related proteins (MIC-A and MIC-B). Soluble molecules (sMIC-A and sMIC-B) can interfere with immune synapsis between NK cells and tumor cells, impeding NK cytotoxicity. The main objectives of this study were to analyze, in dogs with diffuse large B cell lymphoma, NK cell lymphoma, and reactive lymphadenopathies, the role of NK cells, their activating receptors NKG2D and NKp46, and their ligands MIC-A and MIC-B, as well as soluble molecules sMIC-A and sMIC-B. Thirty-six dogs with a possible diagnosis of NHL and eight healthy dogs were studied. NHL was diagnosed in 28 (78 %) dogs; in the other 8 (22 %), reactive lymphadenopathies were present. Most of the lymphomas corresponded to B cell NHL (82 %). The most predominant subtype was diffuse large B cell lymphoma (21, 71.5 %), followed by five cases (18 %) that were Non-B Non-T lymphomas (presumably NK cell lymphomas) and other B cell lymphomas (3, 10.5%). There were no cases of T cell NHL. MIC-A was positive in 7 of 27 (26 %) cases of NHL, and MIC-B in 20 of 27 (74 %) NHL. In non-malignant lymphadenopathies, three (37.5 %) dogs were positive for MIC-A, and five (62.5 %) expressed MIC-B. Dogs with lymphoma had higher numbers of NK cells than eight healthy dogs. In 15 dogs (12 cases with NHL and three cases with reactive adenopathies) and eight controls, there were no differences in the number of NK cells expressing NKP46 and NKG2D. NHL dogs had higher values of sMIC-A and sMIC-B. B-cell and NK cell lymphomas correspond to 86 % and 14 % of all canine lymphomas. MIC-A, MIC-B, and sMIC-A and sMIC-B were increased in canine lymphomas.

非霍德金淋巴瘤（NHL）是人类和狗中最常见的血液恶性肿瘤。NKG2D 是 NK 细胞上最关键的受体之一，识别恶性细胞上的天然配体，例如 A 和 B 主要组织相容性复合体相关蛋白（MIC-A 和 MIC-B）。可溶性分子（sMIC-A和sMIC-B）可以干扰NK细胞和肿瘤细胞之间的免疫突触，阻碍NK细胞毒性。本研究的主要目的是分析患有弥漫性大 B 细胞淋巴瘤、NK 细胞淋巴瘤和反应性淋巴结病的犬中 NK 细胞、其激活受体 NKG2D 和 NKp46 及其配体 MIC-A 和 MIC-B 的作用，以及可溶性分子 sMIC-A 和 sMIC-B。研究人员对 36 只可能诊断为 NHL 的狗和 8 只健康狗进行了研究。28 只 (78%) 狗被诊断出 NHL；其他 8 例 (22%) 存在反应性淋巴结病。大多数淋巴瘤对应于 B 细胞 NHL (82%)。最主要的亚型是弥漫性大 B 细胞淋巴瘤（21 例，71.5%），其次是非 B 非 T 淋巴瘤（推测为 NK 细胞淋巴瘤）5 例（18%）和其他 B 细胞淋巴瘤（3 例，10.5%） ）。没有 T 细胞 NHL 病例。27 例 NHL 病例中有 7 例 (26%) MIC-A 呈阳性，27 例 NHL 病例中有 20 例 (74%) MIC-B 呈阳性。在非恶性淋巴结病中，三只 (37.5%) 狗的 MIC-A 呈阳性，五只 (62.5%) 的狗表达 MIC-B。患有淋巴瘤的狗比八只健康狗的 NK 细胞数量要多。在 15 只狗（12 例患有 NHL 病例和 3 例患有反应性腺病）和 8 只对照犬中，表达 NKP46 和 NKG2D 的 NK 细胞数量没有差异。NHL 狗的 sMIC-A 和 sMIC-B 值较高。B 细胞和 NK 细胞淋巴瘤分别占所有犬类淋巴瘤的 86% 和 14%。犬淋巴瘤中 MIC-A、MIC-B 以及 sMIC-A 和 sMIC-B 升高。