Parekh B S, Hu D J, Vanichseni S, Satten G A, Candal D, Young N L, Kitayaporn D, Srisuwanvilai L O, Rakhtam S, Janssen R, Choopanya K, Mastro T D
Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
AIDS Res Hum Retroviruses. 2001 Mar 20;17(5):453-8. doi: 10.1089/088922201750102562.
The development of a serologic algorithm to determine recent HIV seroconversion, using sensitive/less-sensitive testing strategies, has generated widespread interest in applying this approach to estimate HIV-1 incidence in various populations around the world. To evaluate this approach in non-B subtypes, longitudinal specimens (n = 522) collected from 90 incident infections among injecting drug users in Bangkok (subtype B infection, n = 18; subtype E infection, n = 72) were tested by the 3A11-LS assay. Standardized optical density (SOD) was calculated, using median values, and the window period between seroconversion as determined by sensitive and less sensitive tests was estimated by a maximum-likelihood model described previously. Our results show that the mean window period of the 3A11-LS assay was 155 days (95% CI, 128-189 days) for subtype B but was 270 days (95% CI, 187-349 days) for subtype E specimens from Thailand. About 4% of individuals with incident subtype E infections remained below the threshold (SOD of 0.75), even 2 years after seroconversion. Among the patients with clinical AIDS and declining antibodies, none of the 7 individuals with subtype B, but 10 (8.7%) of 115 with subtype E infections, were misclassified as recent infections. Lowering the cutoff to an SOD of 0.45 for subtype E specimens resulted in a mean window period of 185 days (95% CI, 154-211 days), with all individuals seroconverting, and reduced the number of subtype E-infected patients with AIDS who were misclassified as having recent infection to 2.6%. Our results demonstrate that the 3A11-LS assay has different performance characteristics in detecting recent infections among individuals infected with subtypes B or E. Determining appropriate cutoffs and mean window periods for other HIV-1 subtypes will be necessary before this approach can be reliably implemented in settings where non-B subtypes are common.
利用敏感/低敏感检测策略开发一种用于确定近期HIV血清转化的血清学算法，已引发人们广泛关注将该方法应用于估计全球不同人群中的HIV-1发病率。为了在非B亚型中评估该方法，对从曼谷注射吸毒者中的90例新发感染中收集的纵向标本（n = 522）进行了3A11-LS检测，其中B亚型感染18例，E亚型感染72例。使用中位数计算标准化光密度（SOD），并通过先前描述的最大似然模型估计由敏感和低敏感检测确定的血清转化之间的窗口期。我们的结果显示，3A11-LS检测对于B亚型的平均窗口期为155天（95%置信区间，128 - 189天），而对于来自泰国的E亚型标本则为270天（95%置信区间，187 - 349天）。约4%的新发E亚型感染个体即使在血清转化后2年仍低于阈值（SOD为0.75）。在临床艾滋病患者且抗体下降的患者中，7例B亚型患者中无一例被误分类为近期感染，但115例E亚型感染患者中有10例（8.7%）被误分类为近期感染。将E亚型标本的临界值降至SOD为0.45，导致平均窗口期为185天（95%置信区间，154 - 211天），所有个体均发生血清转化，并将被误分类为近期感染的艾滋病E亚型感染患者数量减少至2.6%。我们的结果表明，3A11-LS检测在检测B或E亚型感染个体中的近期感染时具有不同的性能特征。在非B亚型常见的环境中可靠实施该方法之前，有必要确定其他HIV-1亚型的合适临界值和平均窗口期。
