Reproductive Health and HIV Research Unit, University of the Witwatersrand, PO Box 18512, Hillbrow, Johannesburg 2038, South Africa.
Sex Transm Infect. 2010 Feb;86(1):46-50. doi: 10.1136/sti.2009.036541. Epub 2009 Oct 16.
Sero-epidemiological studies of herpes simplex virus (HSV) type 2 infection in Africa remain difficult to interpret as a result of the high rate of false-positive results observed when using the new recombinant gG2 HSV-2 ELISA tests. The performance of two widely used gG2 ELISA was compared to derive an appropriate testing algorithm for use in South Africa.
Sera from 210 women attending family planning clinics in Johannesburg were tested using HerpeSelect and Kalon HSV-2 gG2 assays. Sera from 20 discordant pairs, 44 concordant positive and 33 concordant negative samples were further tested by HSV Western blot. The sensitivity and specificity of each test and of combination algorithms compared with Western blot were calculated.
HerpeSelect had a sensitivity of 98% (95% CI 95 to 100) and specificity of 61% (95% CI 48 to 74). Kalon was less sensitive (89%, 95% CI 83 to 94) but more specific (85%, 95% CI 61 to 100). Seroprevalence may have been overestimated by as much as 14% by HerpeSelect. Specificity was improved by raising the cut-off index for the determination of a positive result for HerpeSelect (to >or=3.5), but not for Kalon. HIV-1 infection reduced the specificity of HerpeSelect to 30%. Improved sensitivity and specificity were obtained by a two-test algorithm using HerpeSelect (>or=3.5) as the first test and Kalon to resolve equivocal results (sensitivity 92%, 95% CI 82 to 98; specificity 91%, 95% CI 79 to 98).
Newer HSV-2 serological tests have low specificity in this South African population with a high HIV-1 prevalence. Two-step testing strategies could provide rational testing alternatives to Western blot.
由于新的重组 gG2 单纯疱疹病毒 2（HSV-2）ELISA 检测试验中观察到的假阳性率很高，非洲的单纯疱疹病毒 2 型感染血清流行病学研究仍然难以解释。本研究比较了两种广泛使用的 gG2 ELISA，以制定适用于南非的检测算法。
使用 HerpeSelect 和 Kalon HSV-2 gG2 检测试剂盒检测来自约翰内斯堡计划生育诊所的 210 名女性的血清。进一步用 HSV 免疫印迹法检测 20 对不一致、44 对一致阳性和 33 对一致阴性的血清。计算每种检测方法和组合算法与免疫印迹法比较的敏感性和特异性。
HerpeSelect 的敏感性为 98%（95%可信区间 95 至 100），特异性为 61%（95%可信区间 48 至 74）。Kalon 的敏感性较低（89%，95%可信区间 83 至 94），但特异性较高（85%，95%可信区间 61 至 100）。HerpeSelect 可能高估了 14%的血清阳性率。通过提高 HerpeSelect 阳性结果判断的截断指数（>或=3.5）可以提高特异性，但对 Kalon 无效。HIV-1 感染使 HerpeSelect 的特异性降低至 30%。使用 HerpeSelect（>或=3.5）作为初筛，Kalon 解决不确定结果的两步检测算法可获得更高的敏感性和特异性（敏感性 92%，95%可信区间 82 至 98；特异性 91%，95%可信区间 79 至 98）。
在 HIV-1 流行率较高的南非人群中，新型单纯疱疹病毒 2 血清学检测试验特异性较低。两步检测策略可为免疫印迹法提供合理的检测替代方案。
