The Wadsworth Center, New York State Department of Health, Albany, New York, USA
Department of Biomedical Sciences, The School of Public Health, The University at Albany, Albany, New York, USA.
J Clin Microbiol. 2018 Feb 22;56(3). doi: 10.1128/JCM.01591-17. Print 2018 Mar.
The recent outbreak of Zika virus (ZIKV) in the Americas has challenged diagnostic laboratory testing strategies. At the Wadsworth Center, ZIKV serological testing was performed for over 10,000 specimens, using a combination of an enzyme-linked immunosorbent assay (ELISA) for IgM antibodies (Abs) to ZIKV, a polyvalent microsphere immunoassay (MIA) to detect Abs broadly reactive with flaviviruses, and a plaque reduction neutralization test (PRNT) for further testing. Overall, 42% of patients showed serological evidence of flavivirus infection (primarily past dengue virus [DENV] infection), while 7% possessed IgM Abs to ZIKV and/or DENV. ZIKV IgM Abs typically arose within 3 to 4 days, with only one instance of duration beyond 100 days after reported symptoms. PRNT analysis of 826 IgM-positive specimens showed 7% positive neutralization to ZIKV alone, 9% to DENV alone, and 85% to both ZIKV and DENV. Thus, the extensive Ab cross-reactivity among flaviviruses significantly reduced the value of performing PRNT analysis, especially when a traditional paired serum algorithm with viral neutralization titering was used. Nevertheless, the finding of a negative ZIKV result by PRNT was invaluable for reassuring both physicians and patients. The MIA detected both IgM and IgG, which enabled us to identify patients who presented without IgM anti-ZIKV Abs but still had ZIKV-specific neutralizing Abs. On the basis of these results, a new algorithm, which included an IgM Ab capture (MAC)-ELISA to detect recent infection, a flavivirus MIA to identify patients no longer producing IgM, and a single-dilution PRNT for ZIKV exclusion and occasional discrimination of ZIKV and DENV, was implemented.
最近在美洲爆发的 Zika 病毒 (ZIKV) 对诊断实验室检测策略提出了挑战。在 Wadsworth 中心，使用酶联免疫吸附试验 (ELISA) 检测 Zika 病毒 IgM 抗体 (Abs)、多价微球免疫分析 (MIA) 检测广泛与黄病毒反应的 Abs 以及蚀斑减少中和试验 (PRNT) 对 10000 多个标本进行了 Zika 病毒血清学检测。总体而言，42%的患者表现出黄病毒感染的血清学证据（主要是过去的登革热病毒 [DENV] 感染），而 7%的患者具有 Zika 病毒和/或 DENV 的 IgM Abs。Zika 病毒 IgM Abs 通常在 3 到 4 天内出现，只有一例在报告症状后超过 100 天。对 826 份 IgM 阳性标本的 PRNT 分析显示，单独对 Zika 病毒有 7%的阳性中和作用，单独对 DENV 有 9%的中和作用，对 Zika 病毒和 DENV 有 85%的中和作用。因此，黄病毒之间广泛的 Ab 交叉反应显著降低了进行 PRNT 分析的价值，特别是当使用传统的配对血清算法进行病毒中和滴度检测时。然而，PRNT 分析检测到 Zika 病毒的阴性结果对医生和患者都非常有价值。MIA 检测到了 IgM 和 IgG，这使我们能够识别出没有 Zika 病毒 IgM Ab 但仍具有 Zika 病毒特异性中和 Ab 的患者。基于这些结果，实施了一种新的算法，该算法包括用于检测近期感染的 IgM Ab 捕获 (MAC)-ELISA、不再产生 IgM 的黄病毒 MIA 以及用于排除 Zika 病毒和偶尔区分 Zika 病毒和 DENV 的单稀释 PRNT。
