Division of Cancer Epidemiology and Genetics, Infections and Immunoepidemiology Branch, National Cancer Institute, NIH, Bethesda, MD, USA.
Cancer Epidemiol Biomarkers Prev. 2012 Sep;21(9):1547-54. doi: 10.1158/1055-9965.EPI-12-0558. Epub 2012 Jul 2.
Two HPV serological assays, the competitive Luminex immunoassay (cLIA), and an enzyme-linked immunoassay (ELISA) against HPV16 have been used to define HPV-naïve subcohorts within large HPV vaccination trials. Some of the variation in estimated vaccine efficacies may be due to the differences in these assays used to define the HPV-naïve subgroups. To guide the interpretation of published results, we compared these assays.
Replicate enrollment sera from a stratified sample of 388 unvaccinated women from the control arm of the Costa Rica HPV 16/18 Vaccine Trial were measured for antibodies against HPV16 using cLIA and ELISA. Agreement between the assays was estimated using standard and alternative assay cutoffs.
Using laboratory-determined seropositivity cutoffs, sampling-adjusted HPV16 seropositivity was 24.8% by ELISA and 7.2% by cLIA. Comparing cLIA and ELISA antibody levels based on the standard cutoffs, overall agreement was 53% (positive-agreement = 49%). The poor agreement was mainly driven by the higher sensitivity of the ELISA than cLIA, resulting in 30% of the ELISA-positive sample that were cLIA-negative (none of the ELISA-negatives were cLIA-positive). Increasing ELISA cutoff to 54 ELISA units (EU)/mL (the level which maximized agreement with cLIA; ELISA standard cutoff is 8 EU/mL) resulted in higher agreement (overall agreement = 91%; positive agreement = 78%).
ELISA and cLIA are different from each other based on the laboratory-determined cutoff. Increasing ELISA cutoff increased agreement with cLIA, which could facilitate comparisons among studies that use different assays.
Keeping cLIA at the laboratory-determined cutoff but altering ELISA cutoff for seropositivity might facilitate vaccine efficacy comparisons in the naïve cohorts defined by cLIA.
两种 HPV 血清学检测方法，竞争 Luminex 免疫测定法（cLIA）和针对 HPV16 的酶联免疫吸附测定法（ELISA）已被用于在大型 HPV 疫苗试验中确定 HPV 初免亚组。估计疫苗效力的一些差异可能是由于用于定义 HPV 初免亚组的这些检测方法的差异所致。为了指导对已发表结果的解释，我们比较了这些检测方法。
对哥斯达黎加 HPV 16/18 疫苗试验对照组中分层抽样的 388 名未接种疫苗的女性的复制入组血清，使用 cLIA 和 ELISA 检测针对 HPV16 的抗体。使用标准和替代检测截止值来估计检测方法之间的一致性。
使用实验室确定的血清阳性检测截止值，ELISA 检测的 HPV16 血清阳性率为 24.8%，cLIA 检测的 HPV16 血清阳性率为 7.2%。根据标准截止值比较 cLIA 和 ELISA 抗体水平，总体一致性为 53%（阳性一致性=49%）。这种较差的一致性主要是由于 ELISA 的灵敏度高于 cLIA，导致 ELISA 阳性样本中有 30%为 cLIA 阴性（无 ELISA 阴性样本为 cLIA 阳性）。将 ELISA 截止值增加到 54 ELISA 单位（EU）/mL（最大程度提高与 cLIA 一致性的水平；ELISA 标准截止值为 8 EU/mL）可提高一致性（总体一致性=91%；阳性一致性=78%）。
根据实验室确定的截止值，ELISA 和 cLIA 彼此不同。增加 ELISA 截止值可提高与 cLIA 的一致性，这有助于比较使用不同检测方法的研究。
保持 cLIA 处于实验室确定的截止值，但改变 ELISA 截止值以确定血清阳性状态，可能有助于在 cLIA 确定的初免亚组中比较疫苗效力。
