Khalil Salem H, Hamadah Issam R
Department of Pathology and Laboratory Medicine (MBC-10), King Faisal Specialist Hospital and Research Center, PO Box 3354, Riyadh 11211, Kingdom of Saudi Arabia.
Saudi Med J. 2006 Jul;27(7):951-4.
The diagnosis of cutaneous T-cell lymphoid infiltrates may be difficult based on clinical and routine immunohistologic findings. In this situation, an ancillary technique demonstrating the presence of a monoclonal cell proliferation could help to rule in or out cutaneous T-cell lymphoma (CTCL) in cases that clinically and histopathologically do not allow a definitive diagnosis. Southern blot analysis is a time-consuming method with low sensitivity that should not be considered for the routine diagnosis of cutaneous lymphoid infiltrates. Moreover, it can be used only when fresh tissue is available. New assays based on the amplification of the T-cell receptor gamma (TCR gamma) chain gene rearrangement by polymerase chain reaction (PCR) have been proposed to overcome these limitations.
We retrospectively studied 124 biopsies from 104 patients (66 biopsies with the clinical and histological diagnosis or suspicious of CTCL and 58 biopsies with histological diagnosis of benign reactive dermatological conditions who presented to the Dermatology Unit at King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia between 1996 and 2004. The specimens were morphologically examined and then analyzed by PCR for the gamma chain of the TCR gamma followed by gel electrophoresis.
The results showed 87.1% sensitivity and 92% specificity in detecting clonal T-cell gene rearrangements among CTCL cases with a positive predictive value of 93.1% and negative predictive value of 85.2%. Therefore, negative TCR gamma results in CTCL should be taken with caution.
The detection of clonal TCR gamma gene rearrangement by PCR based method is an adjuvant diagnostic marker for CTCL, although it can be seen in some benign dermatoses.
基于临床和常规免疫组织学检查结果，皮肤T细胞淋巴浸润的诊断可能存在困难。在此情况下，一项能证明单克隆细胞增殖存在的辅助技术有助于在临床和组织病理学无法做出明确诊断的病例中排除或确诊皮肤T细胞淋巴瘤（CTCL）。Southern印迹分析是一种耗时且灵敏度低的方法，不应被用于皮肤淋巴浸润的常规诊断。此外，它仅在有新鲜组织时才能使用。基于聚合酶链反应（PCR）扩增T细胞受体γ（TCRγ）链基因重排的新检测方法已被提出以克服这些局限性。
我们回顾性研究了1996年至2004年间在沙特阿拉伯利雅得法赫德国王专科医院和研究中心皮肤科就诊的104例患者的124份活检样本（66份临床和组织学诊断或怀疑为CTCL的活检样本以及58份组织学诊断为良性反应性皮肤病的活检样本）。对标本进行形态学检查，然后通过PCR检测TCRγ的γ链，随后进行凝胶电泳分析。
结果显示，在检测CTCL病例中的克隆性T细胞基因重排时，灵敏度为87.1%，特异性为92%，阳性预测值为93.1%，阴性预测值为85.2%。因此，CTCL中TCRγ结果为阴性时应谨慎对待。
基于PCR方法检测克隆性TCRγ基因重排是CTCL的辅助诊断标志物，尽管在一些良性皮肤病中也可见到。
