Prince A M, Scheffel J W, Moore B
Laboratory of Virology and Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, USA.
Transfusion. 1997 Feb;37(2):211-4. doi: 10.1046/j.1537-2995.1997.37297203526.x.
Previous studies reported the existence of hepatitis C virus (HCV) polymerase chain reaction (PCR)-positive but seronegative sera. This is not surprising in the case of window-phase specimens, because PCR can detect HCV RNA many weeks before the appearance of antibody. To determine whether such sera can also be found in chronically infected subjects, a high-risk population of blood donors with elevated alanine aminotransferase was studied.
Freshly frozen plasma from 301 donors with alanine aminotransferase > 100 IU per L was tested with PCR assays that were rigidly controlled for specificity and contamination, and with current and newer versions of assays for anti-HCV. Sera were classified as seropositive if positive in two screening assays and one supplemental assay or if positive in two screening assays and PCR.
New versions of screening assays detected 100 percent of seropositive samples. A second-generation immunoblot assay detected 98 percent of seropositive sera, a second-generation recombinant immunoblot assay detected 96 percent, and an enzyme immunoassay for antibody to the envelope protein of HCV detected 98 percent. Fifty-one of 54 seropositive sera were PCR positive. None of the 247 seronegative samples was reproducibly positive on PCR.
No PCR-positive but seronegative donors were found in this high-risk donor population. The possible benefit of PCR screening of blood donors can be determined only by large-scale comparative testing of donor populations and may be limited to the detection of window-phase infections.
以往研究报道了丙型肝炎病毒（HCV）聚合酶链反应（PCR）检测呈阳性但血清学检测呈阴性的血清的存在。对于窗口期标本而言，出现这种情况并不奇怪，因为PCR能够在抗体出现前数周检测到HCV RNA。为了确定在慢性感染个体中是否也能发现此类血清，我们对丙氨酸氨基转移酶升高的高危献血者群体进行了研究。
采用严格控制特异性和污染的PCR检测方法，以及现行和更新版本的抗HCV检测方法，对301名丙氨酸氨基转移酶>100 IU/L的献血者的新鲜冷冻血浆进行检测。如果在两次筛查检测和一次补充检测中呈阳性，或者在两次筛查检测和PCR检测中呈阳性，则血清被分类为血清阳性。
新版本的筛查检测方法检测到了100%的血清阳性样本。第二代免疫印迹检测方法检测到了98%的血清阳性血清，第二代重组免疫印迹检测方法检测到了96%，以及一种针对HCV包膜蛋白抗体的酶免疫检测方法检测到了98%。54份血清阳性血清中有51份PCR检测呈阳性。247份血清阴性样本中没有一份在PCR检测中可重复呈阳性。
在这个高危献血者群体中未发现PCR检测呈阳性但血清学检测呈阴性的献血者。只有通过对献血者群体进行大规模比较检测，才能确定对献血者进行PCR筛查可能带来的益处，而且其益处可能仅限于检测窗口期感染。
