Toxoplasma Serology Laboratory, Palo Alto Medical Foundation, Palo Alto, California, USA
Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
J Clin Microbiol. 2019 Jan 30;57(2). doi: 10.1128/JCM.01357-18. Print 2019 Feb.
This study evaluated the usefulness of adding the IgA antibody enzyme-linked immunosorbent assay (ELISA) to the serologic panel of tests done for the diagnosis of acute toxoplasmosis in pregnant women in a reference laboratory in the United States. We conducted a retrospective study of 690 consecutive pregnant women with positive IgG antibody test results who also had IgA and IgM antibody tests performed. Patients were defined as acutely or chronically infected with based on a panel of serologic tests performed at the Palo Alto Medical Foundation Toxoplasma Serology Laboratory (PAMF-TSL). Among the 81 women who were positive by IgA antibody ELISA testing, 61 (75.3%) were acutely infected with , while of the 547 who were negative by IgA testing, only 24 (4.4%) were acutely infected ( < 0.001). Among the 71 women who were positive by both IgA and IgM antibody tests, 61 (85.9%) were acutely infected, whereas 24 (19.2%) of the 125 women who were positive by only the IgM ELISA were acutely infected ( < 0.001). These results demonstrate that pregnant women with IgA antibodies are more likely than pregnant women without IgA antibodies to have had a recent infection with IgA antibody testing can therefore improve the accuracy of a serologic panel for the diagnosis of acute toxoplasmosis during pregnancy. Physicians who ordered testing only for IgG and IgM should also request additional testing for IgA and IgG avidity, if both IgG and IgM are positive. This further testing should, ideally, be performed in a reference laboratory.
这项研究评估了在一家美国参考实验室的血清学检测中添加 IgA 抗体酶联免疫吸附试验（ELISA）对诊断孕妇急性弓形虫病的有用性。我们对 690 例连续的 IgG 抗体检测阳性的孕妇进行了回顾性研究，这些孕妇还进行了 IgA 和 IgM 抗体检测。根据 Palo Alto 医学基金会弓形虫血清学实验室（PAMF-TSL）进行的一组血清学检测，将患者定义为急性或慢性感染。在 81 例 IgA 抗体 ELISA 检测阳性的妇女中，有 61 例（75.3%）为急性感染，而在 547 例 IgA 检测阴性的妇女中，只有 24 例（4.4%）为急性感染（<0.001）。在 71 例 IgA 和 IgM 抗体检测均阳性的妇女中，有 61 例（85.9%）为急性感染，而在仅 IgM ELISA 检测阳性的 125 例妇女中，有 24 例（19.2%）为急性感染（<0.001）。这些结果表明，与没有 IgA 抗体的孕妇相比，IgA 抗体阳性的孕妇更有可能发生近期感染。因此，IgA 抗体检测可以提高妊娠期间急性弓形虫病血清学检测的准确性。仅为 IgG 和 IgM 检测开单的医生也应该要求对 IgA 和 IgG 亲和力进行额外检测，如果 IgG 和 IgM 均为阳性。理想情况下，应在参考实验室进行进一步检测。
