Department of Biology, Payam Noor University (PNU), Tehran, Iran.
Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
J Obstet Gynaecol Res. 2022 Oct;48(10):2479-2485. doi: 10.1111/jog.15349. Epub 2022 Jul 6.
It has been generally believed that women who exposed to Toxoplasma gondii before pregnancy and have anti-T. gondii IgG antibody are immunized and their newborns will be protected from congenital infection. This study is aimed to investigate the role of T. gondii infection in spontaneous abortion through serological and molecular methods in southern Iran.
Blood samples were taken from 50 spontaneously aborted mothers and anti-T. gondii antibodies were assessed using conventional enzyme-linked immunosorbent assay (ELISA) and avidity ELISA methods. The placenta and blood samples of aborted women were used for detection of the parasite's DNA by polymerase chain reaction (PCR) method targeting the RE gene. The parasite genotypes were determined by PCR-restriction fragment length polymorphism (RFLP) method using SAG3 and GRA6 genes.
IgG antibody was detected in 28% (14/50) of mothers, but all samples were negative for IgM antibody. In the avidity ELISA test, 26% (13/50) of the samples had a high avidity index, suggesting chronic infection, while a low avidity index was detected in one case (2%), which suggests acute infection. The parasite's DNA was detected in 18% (9/50) and 14% (7/50) of blood and placenta samples, respectively. All DNA positive samples were IgG positive. All isolates were belonged to the T. gondii type III genotype.
The results suggest that T. gondii seropositive women are not protected from congenital transmission. However, the results should be interpreted cautiously until further studies will be confirmed these results.
人们普遍认为，妊娠前感染弓形虫并具有抗弓形虫 IgG 抗体的女性已被免疫，其新生儿将免受先天性感染。本研究旨在通过血清学和分子方法在伊朗南部调查弓形虫感染在自然流产中的作用。
采集 50 例自然流产母亲的血样，采用传统酶联免疫吸附试验（ELISA）和亲和力 ELISA 方法检测抗弓形虫抗体。使用聚合酶链反应（PCR）方法针对 RE 基因检测流产妇女胎盘和血液样本中的寄生虫 DNA。采用 PCR-限制性片段长度多态性（RFLP）方法，使用 SAG3 和 GRA6 基因确定寄生虫基因型。
母亲中 IgG 抗体的检出率为 28%（14/50），但所有样本均为 IgM 抗体阴性。在亲和力 ELISA 检测中，26%（13/50）的样本具有高亲和力指数，提示慢性感染，而一例（2%）检测到低亲和力指数，提示急性感染。在血液和胎盘样本中，分别有 18%（9/50）和 14%（7/50）检测到寄生虫 DNA。所有 DNA 阳性样本均为 IgG 阳性。所有分离株均属于弓形虫 III 型基因型。
结果表明，弓形虫血清阳性的妇女不能免受先天性传播。然而，在进一步的研究证实这些结果之前，这些结果应谨慎解释。
