Dubois F, Barin F, Goudeau A
Laboratoire de virologie EP CNRS 117, Centre hospitalier universitaire, Bretonneau, Tours, Cedex.
Ann Biol Clin (Paris). 1998 Jul-Aug;56(4):417-26.
Screening for antibody to hepatitis C virus (anti-HCV) is usually carried out using microplate enzyme immunoassays (EIA). According to French Ministry of Health recommendations, any positive or dubious result has to be controlled on a second blood sample with a anti-HCV assay differing from the one used for the initial screening. This second test can either be another EIA or an immunoblot assay. The present article investigates the advantage of a strip immunoblot assay including 4-viral peptides (Riba-3) for this control. The use of Riba for the early diagnosis of hepatitis C infection and for the follow-up of infected patients is also evaluated. Riba can be used to assess false positive EIA reactions, for instance in cases with isolated antibody to NS5. From large clinical series, it appears that positive Riba serum profiles can be divided in two main groups: Strongly positive sera associate at least strong (3 or 4+) anti-capsid and anti-NS3 antibody reactivities. These profiles are often completed by anti-NS4 and/or anti-NS5 reactivities. Such profiles are associated with HCV viremia in about 90% of the cases. In this group, prevalence of viremia reaches 100% in patients with elevated level of serum alanin aminotransferase (ALT) and is slightly less frequent, 85%, in patients with normal level of ALT; Weakly positive sera lack either anti-capsid or anti-NS3 antibodies or exhibit only low reactivities (1+ or 2+) to these two antigens. These profiles can also be associated with antibodies to NS4 and/or NS5. Only 10% of patients with such Riba profiles are viremic. Weakly positive profile can be encountered during the early phase of HCV infection (recent seroconversion) or in patients who experience a favourable evolution of their HCV infection. Change of Riba profiles during follow-up provides fruitful information on recent seroconversions (increase in number and intensity of the reactivities). It can also help predict the outcome of HCV infection, a diminution of the intensity of Riba reactivities will confirm the extinction of viral replication.
丙型肝炎病毒抗体（抗-HCV）筛查通常采用微孔板酶免疫测定法（EIA）进行。根据法国卫生部的建议，任何阳性或可疑结果都必须在第二份血样上使用与初次筛查不同的抗-HCV检测方法进行复查。第二次检测可以是另一种EIA或免疫印迹检测。本文研究了包含4种病毒肽的条带免疫印迹检测法（Riba-3）用于这种复查的优势。还评估了Riba在丙型肝炎感染早期诊断及感染患者随访中的应用。Riba可用于评估EIA假阳性反应，例如在仅存在NS5抗体的情况下。从大量临床系列研究来看，Riba血清阳性结果可分为两个主要组：强阳性血清至少伴有强（3或4+）抗衣壳和抗NS3抗体反应性。这些结果通常还伴有抗NS4和/或抗NS5反应性。此类结果在约90%的病例中与HCV病毒血症相关。在该组中，血清丙氨酸氨基转移酶（ALT）水平升高的患者病毒血症患病率达100%，而ALT水平正常的患者中病毒血症患病率略低，为85%；弱阳性血清缺乏抗衣壳或抗NS3抗体，或对这两种抗原仅表现出低反应性（1+或2+）。这些结果也可能与抗NS4和/或NS5抗体相关。仅有10%具有此类Riba结果的患者存在病毒血症。弱阳性结果可在HCV感染早期（近期血清转换）或HCV感染病情好转的患者中出现。随访期间Riba结果的变化可为近期血清转换（反应性数量和强度增加）提供有用信息。它还可帮助预测HCV感染的结局，Riba反应性强度降低将证实病毒复制停止。
