Aoyagi K, Iida K, Ohue C, Matsunaga Y, Tanaka E, Kiyosawa K, Yagi S
Advanced Life Science Institute, Inc., Saitama, Japan.
Clin Lab. 2001;47(3-4):119-27.
There are periods within the early phase of hepatitis C virus (HCV) infection in which the anti-HCV antibody test is unable to confirm HCV viremia. To reduce the risk of transmitting HCV through transfusions, we developed a simple and highly sensitive enzyme immunoassay (EIA) which detects the core antigen of HCV (HCVcAg). This assay employed a conventional colorimetric EIA system, and was based on a two-step sandwich assay, using a 96- well microplate. The reproducibility of the results was very high. When the cutoff values were set to 30 fmol of recombinant HCVcAg/L, as determined by the distribution of healthy subject sera (n=223), 99.6% of healthy subject sera and 100% of hepatitis B patient sera (n=50) were negative for HCVcAg. The clinical performance of this EIA was examined using 14 commercially available seroconversion panels. In every panel, HCVcAg could be detected at points preceding the seroconversion of anti-HCV antibodies. The points at which HCVcAg was detected were the same as those at which it was detected by an AMPLICOR HCV Monitor test. The EIA's window period for detecting the HCVcAg in all panels was on average 26 days shorter than that of the anti-HCV antibody test. In three panels where the first sample is negative for HCV RNA, the window period was shortened 50 days by this EIA for HCVcAg. There was a positive correlation between the concentration of HCVcAg and HCV RNA in anti-HCV antibody negative specimens. This assay was simpler to perform than assays based on gene amplification technology for the detection of HCV RNA, and the window period was shortened to that of the AMPLICOR HCV Monitor test. Thus, the EIA for HCVcAg would be useful in screening seroconverting donors and could reduce the residual risk of secondary HCV infections through transfusions.
在丙型肝炎病毒（HCV）感染的早期阶段，存在抗-HCV抗体检测无法确认HCV病毒血症的时期。为降低通过输血传播HCV的风险，我们开发了一种简单且高度灵敏的酶免疫测定法（EIA），用于检测HCV的核心抗原（HCVcAg）。该测定法采用传统的比色EIA系统，基于两步夹心测定法，使用96孔微孔板。结果的重现性非常高。根据健康受试者血清（n = 223）的分布确定，当临界值设定为重组HCVcAg/L 30 fmol时，99.6%的健康受试者血清和100%的乙型肝炎患者血清（n = 50）HCVcAg呈阴性。使用14个市售的血清学转换检测板检测了该EIA的临床性能。在每个检测板中，在抗-HCV抗体血清学转换之前的时间点均可检测到HCVcAg。检测到HCVcAg的时间点与通过AMPLICOR HCV监测检测法检测到的时间点相同。该EIA在所有检测板中检测HCVcAg的窗口期平均比抗-HCV抗体检测短26天。在三个首个样本HCV RNA为阴性的检测板中，该HCVcAg EIA将窗口期缩短了50天。在抗-HCV抗体阴性标本中，HCVcAg浓度与HCV RNA之间存在正相关。该测定法比基于基因扩增技术检测HCV RNA的测定法操作更简单，窗口期缩短至与AMPLICOR HCV监测检测法相同。因此，HCVcAg EIA在筛查血清学转换的献血者方面将很有用，并可降低输血导致继发性HCV感染的残留风险。
