當前診斷丙型肝炎病毒（HCV）感染的標準方法需要兩個連續的步驟：用於篩選的HCV抗體測試，隨後進行HCV RNA RT-PCR測試來驗證病毒血症性HCV（viremic HCV, V-HCV）感染（編者注：即導致病毒血症的HCV感染）。這使得它未最優化、成本高、不方便、耗時和不能夠在全球廣泛使用或負擔得起。

　　HCV核心抗原（HCVcAg）測試有潛力提供一步法診斷HCV感染。然而，它的靈敏度和特異性較低限製了它的臨床應用。

　　在一項新的研究中，來自美國加州大學歐文分校的研究人員開發出一種新的HCV抗原酶免疫測定法（HCV-Ags EIA），並利用365種血清樣品（其中，176種未發生V-HCV感染，189種發生V-HCV感染）評估了這種一步法診斷V-HCV感染的靈敏度、特異性和實用性。相關研究結果於2016年6月6日在線發表在Hepatology期刊上，論文標題為“A Highly Specific and Sensitive Hepatitis C Virus Antigens Enzyme Immunoassay for One-step Diagnosis of Viremic HCV Infection”。

　　首先，研究人員證實在HCV感染期間，除了HCV核心抗原之外，還存在HCV NS3、NS4b和NS5a蛋白。基於此，他們開發出這種新的同時檢測這四種HCV蛋白的HCV-Ags EIA方法。

　　這項研究首次證實血清樣品變性導致釋放出的HCV抗原以HCV免疫複合物的形式存在，從而降低測試特異性，因此應當不能夠用於任何HCV抗原測試，包括所有當前的HCV核心抗原測試。

　　另一方麵，與血清HCV抗體測試和HCV RNA RT-PCR測試的結果相比較，利用未變性的血清樣品，這種HCV-Ags EIA測試結果的特異性為99%，靈敏度為100%。

　　利用未變性的進行過稀釋的血清樣品進行測試，這種HCV-Ags EIA方法的最低檢測限相當於大約150～250 IU/mL的血清HCV RNA水平。

　　研究人員開發出的這種HCV-Ags EIA方法是高度特異性的和高度靈敏的。利用未變性的血清樣品，這種HCV-Ags EIA方法能夠可靠地區分V-HCV感染和已得到控製的HCV感染，而且是一步法實現對V-HCV感染的篩選和診斷。

　　論文作者寫道，“慢性HCV感染影響全世界大約1.7億人，並且與發展為肝硬化和肝細胞癌的風險相關聯。盡管衛生專業實踐指導方針主張對HCV感染進行篩選，但是最近的研究表明在HCV感染的篩選和診斷方麵還存在重大的缺口。”

　　A Highly Specific and Sensitive Hepatitis C Virus Antigens Enzyme Immunoassay for One-step Diagnosis of Viremic HCV Infection

　　doi:10.1002/hep.28663

　　Ke-Qin Hu,Wei Cui

　　The current standard in diagnosing HCV infection requires 2 sequential steps: anti-HCV test to screen, followed by HCV RNA RT-PCR to confirm viremic HCV (V-HCV) infection. HCV core antigen (HCVcAg) tests provided potential for possible one-step diagnosis. However, low sensitivity and specificity limit their clinical utility. The present study developed a novel HCV antigens enzyme immunoassay (HCV-Ags EIA) and assessed its sensitivity, specificity, and utility for one-step diagnosis of V-HCV infection using 365 serum specimens, including 176 without, and 189 with V-HCV infection. First, we confirmed presence of HCV non-structural protein 3 (NS3), NS4b, and NS5a proteins besides HCVcAg during HCV infection, and developed a novel HCV-Ags EIA via simultaneous detection of all these 4 HCV proteins. For the first time, the presented study demonstrated that serum sample denaturation decreases the test specificity due to release of HCV-Ags sequestered in HCV-immune complexes, and should not be used in any HCV-Ags, including all the current HCVcAg assays. On the other hand, using sample non-denaturation, the HCV-Ags EIA results showed 99% specificity and 100% sensitivity compared to serum anti-HCV and HCV RNA RT-PCR results. Using serum sample dilution, and non-denaturation, the lowest limits of detection of the HCV-Ags EIA were equivalent to serum HCV RNA levels of approximate 150-250 IU/mL. CONCLUSIONS: The highly specific and sensitive HCV-Ags EIA developed in the present study has the lowest limit of detection equivalent to serum HCV RNA levels of 150-250 IU/mL. Using non-denaturation of serum samples, our HCV-Ags EIA reliably differentiated V-HCV infection from resolved HCV infection, accomplishes screening and diagnosis of V-HCV infection in one step. This article is protected by copyright. All rights reserved.