Matsuda Ikuo, Sugihara Nao, Yunokizaki Hiroshi, Abe Takashi, Hirota Seiichi
Department of Surgical Pathology, Hyogo College of Medicine Hyogo, Japan.
Department of Gastroenterology, Takarazuka Municipal Hospital Hyogo, Japan ; Second Department of Internal Medicine, National Defense Medical College Saitama, Japan.
Int J Clin Exp Pathol. 2015 Jan 1;8(1):1019-24. eCollection 2015.
Precise immunophenotyping of tumor cells by immunohistochemistry is complementary to morphological examination. It is critical for the correct histopathological diagnosis of lymphomas. In this paper, we report a case of T-cell lymphoma whose histopathological diagnosis was confounded by an immunohistochemical pitfall: a false positive caused by incompatibility between an antibody and an autostainer. In this case, based on CD4 immunohistochemistry of the affected lymph nodes, the T-cell lymphoma was diagnosed as CD4-positive at the onset, while it appeared discordantly to be CD4-negative at the second relapse. We noticed that CD4 antibodies and autostainers of different suppliers (designated as suppliers X and Y) were used in an unqualified combination in immunohistochemistry at the onset: that is, the combination of an antibody supplied by X and an autostainer supplied by Y (designated as X-Y combination) was used at the onset. On the other hand, the Y-Y combination was at the second relapse. At the second relapse, flow cytometry of the affected lymph node showed infiltration of CD4-negative T-cell lymphoma. We reasoned that CD4 immunonegativity obtained by the Y-Y combination at the second relapse was specific, while CD4 immunopositivity by the X-Y combination at the onset was false positive. Immunohistochemical reexamination of the lymph node at the onset proved to be CD4-negative by not only the Y-Y but also X-X combinations, confirming our final diagnosis of nodal relapse of CD4-negative T-cell lymphoma. This case illustrates the importance of using compatible combinations of antibodies and autostainers in diagnostic immunohistochemistry.
通过免疫组织化学对肿瘤细胞进行精确的免疫表型分析是对形态学检查的补充。这对于淋巴瘤的正确组织病理学诊断至关重要。在本文中，我们报告了一例T细胞淋巴瘤病例，其组织病理学诊断因免疫组织化学陷阱而混淆：一种抗体与自动染色仪不兼容导致假阳性。在该病例中，基于受累淋巴结的CD4免疫组织化学，T细胞淋巴瘤在发病时被诊断为CD4阳性，而在第二次复发时却不一致地表现为CD4阴性。我们注意到，发病时免疫组织化学中使用了不同供应商（指定为供应商X和Y）的CD4抗体和自动染色仪，即发病时使用了X供应商提供的抗体与Y供应商提供的自动染色仪的组合（指定为X-Y组合）。另一方面，第二次复发时使用的是Y-Y组合。在第二次复发时，受累淋巴结的流式细胞术显示为CD4阴性T细胞淋巴瘤浸润。我们推断，第二次复发时通过Y-Y组合获得的CD4免疫阴性是特异性的，而发病时X-Y组合的CD4免疫阳性是假阳性。对发病时的淋巴结进行免疫组织化学复查，不仅通过Y-Y组合，而且通过X-X组合均证实为CD4阴性，从而证实了我们对CD4阴性T细胞淋巴瘤淋巴结复发的最终诊断。该病例说明了在诊断性免疫组织化学中使用兼容的抗体和自动染色仪组合的重要性。
