Background Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infections in children <2 years of age. Prior infection in a child is usually determined by RSV antibodies; however, in young children, persisting maternal immunoglobulin G antibodies can incorrectly indicate past RSV infection. We developed and evaluated 4 immunoglobulin A (IgA) antibody enzyme immunoassays (EIAs) with the RSV F, subgroup G (Ga or Gb proteins) or RSV lysate antigens to distinguish infection induced from persisting maternal RSV antibodies. Methods We tested the EIAs against 62 cord blood specimens (group A), 39 plasma specimens from infants not exposed to an RSV season (group B), 102 plasma specimens from infants with a documented RSV infection (group C), and 124 plasma specimens from infants exposed to their first RSV season but without a documented RSV infection (group D). Results Among the 2 negative control groups, no group A specimens and 1 of the group B specimens were positive in all 4 IgA EIAs, giving a specificity of 100% and 97%, respectively. The sensitivity of the F, Ga, Gb, and Lysate IgA EIAs were 88%, 31%, 26%, and 61%, respectively, for group C specimens. Forty-four percent of the 124 specimens in group D were positive in the RSV-F IgA EIA. Conclusions The RSV-F protein IgA EIA exhibited a high level of sensitivity and specificity for detecting previous RSV infections in the presence of maternal antibodies and can help in RSV clinical trials and epidemiologic studies in young children.

中文翻译：

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免疫球蛋白 A 酶免疫测定法检测婴幼儿原发性呼吸道合胞病毒感染的评价


背景 呼吸道合胞病毒 （RSV） 是 <2 岁儿童急性下呼吸道感染的主要原因。儿童的既往感染通常由 RSV 抗体决定;然而，在幼儿中，持续的母体免疫球蛋白 G 抗体可以错误地表明过去的 RSV 感染。我们开发并评估了 4 种免疫球蛋白 A （IgA） 抗体酶免疫测定 （EIA），其中包含 RSV F、亚群 G （Ga 或 Gb 蛋白） 或 RSV 裂解物抗原，以区分感染诱导的感染和持续的母体 RSV 抗体。方法 我们对照 62 份脐带血标本（A 组）、39 份未暴露于 RSV 季节的婴儿血浆标本（B 组）、102 份来自有记录的 RSV 感染婴儿的血浆标本（C 组）和 124 份来自暴露于第一个 RSV 季节但没有记录的 RSV 感染的婴儿的血浆标本（D 组）。结果 2 个阴性对照组中，4 个 IgA EIAs 均无 A 组标本和 1 个 B 组标本呈阳性，特异性分别为 100% 和 97%。对于 C 组样本，F、Ga、Gb 和 Lysate IgA EIAs 的敏感性分别为 88%、31%、26% 和 61%。D 组 124 例标本中有 44% 在 RSV-F IgA EIA 中呈阳性。结论 RSV-F 蛋白 IgA EIA 在存在母源抗体的情况下对检测既往 RSV 感染表现出高水平的敏感性和特异性，有助于幼儿的 RSV 临床试验和流行病学研究。