CD71 is an immunohistochemical marker used in diagnosing acute myeloid leukemia (AML) M6-Er in humans; however, to our knowledge, it has not been reportedly used for immunohistochemistry in veterinary medicine. We evaluated the pathologic features of AML M6-Er in a retrovirus-negative cat and used CD71 to support the diagnosis. A 4-y-old spayed female Scottish Fold cat was presented with lethargy, anorexia, and fever. Whole-blood PCR assay results for pro feline leukemia virus/pro feline immunodeficiency virus and feline vector-borne diseases were negative. Early erythroid precursors were observed in the peripheral blood smear. Fine-needle aspiration of the enlarged spleen and splenic lymph node showed many early erythroid precursors. Bone marrow aspirate smears revealed erythroid hyperplasia with 68.4% erythroid lineage and 3.6% rubriblasts. Dysplastic cells infiltrated other organs. The patient was diagnosed with myelodysplastic syndrome, progressing to the early phase of AML M6-Er. The patient died on day 121 despite multidrug treatments. Postmortem examination revealed neoplastic erythroblasts infiltrating the bone marrow and other organs. Neoplastic cells were immunopositive for CD71 but immunonegative for CD3, CD20, granzyme B, von Willebrand factor, CD61, myeloperoxidase, and Iba-1. Although further studies are necessary for the application of CD71, our results supported the morphologic diagnosis of AML M6-Er.

CD71 是一种免疫组织化学标志物，用于诊断人类急性髓系白血病 (AML) M6-Er；然而，据我们所知，据报道它尚未用于兽医学中的免疫组织化学。我们评估了逆转录病毒阴性猫 AML M6-Er 的病理特征，并使用 CD71 来支持诊断。一只 4 岁已绝育的雌性苏格兰折耳猫出现嗜睡、厌食和发烧。原猫白血病病毒/原猫免疫缺陷病毒和猫媒介传播疾病的全血 PCR 检测结果为阴性。在外周血涂片中观察到早期红细胞前体。扩大的脾脏和脾淋巴结的细针抽吸显示许多早期红系前体。骨髓穿刺涂片显示红系增生，红系为 68.4%，红系为 3.6%。发育不良细胞浸润其他器官。该患者被诊断为骨髓增生异常综合征，进展到 AML M6-Er 的早期阶段。尽管接受了多种药物治疗，该患者仍于第 121 天死亡。尸检显示肿瘤性成红细胞浸润骨髓和其他器官。肿瘤细胞对 CD71 呈免疫阳性，但对 CD3、CD20、颗粒酶 B、血管性血友病因子、CD61、髓过氧化物酶和 Iba-1 呈免疫阴性。尽管 CD71 的应用还需要进一步研究，但我们的结果支持 AML M6-Er 的形态学诊断。尸检显示肿瘤性成红细胞浸润骨髓和其他器官。肿瘤细胞对 CD71 呈免疫阳性，但对 CD3、CD20、颗粒酶 B、血管性血友病因子、CD61、髓过氧化物酶和 Iba-1 呈免疫阴性。尽管 CD71 的应用还需要进一步研究，但我们的结果支持 AML M6-Er 的形态学诊断。尸检显示肿瘤性成红细胞浸润骨髓和其他器官。肿瘤细胞对 CD71 呈免疫阳性，但对 CD3、CD20、颗粒酶 B、血管性血友病因子、CD61、髓过氧化物酶和 Iba-1 呈免疫阴性。尽管 CD71 的应用还需要进一步研究，但我们的结果支持 AML M6-Er 的形态学诊断。