Toxoplasmosis Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran.
Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran.
BMC Pregnancy Childbirth. 2024 Nov 22;24(1):771. doi: 10.1186/s12884-024-06979-x.
Toxoplasmosis, a prevalent parasitic infection, is primarily caused by Toxoplasma gondii (T. gondii). This infection poses a significant threat to neonates during pregnancy and individuals with compromised immune systems. Consequently, it is imperative to develop a novel diagnostic approach that combines high sensitivity with low-risk sampling to effectively manage patients. The aim of this study is to utilize serological and molecular techniques for the diagnosis of T. gondii infection in 100 pregnant women who were under the care of a gynecologist and were candidates for amniocentesis.
During the 15-19th weeks of pregnancy, a total of 100 samples each of amniotic fluid, buffy coat, plasma, and urine simultaneously were collected from pregnant women candidates for amniocentesis in Mazandaran province, northern Iran. This study involved various assessments: (1) detecting anti-T. gondii IgM and IgG in plasma through chemiluminescence assay (2) determining IgG avidity in plasma using the Enzyme-linked immunosorbent assay technique (3) identifying of T. gondii DNA in amniotic fluid, buffy coat and urine by nested PCR (nPCR) and quantitative real-time PCR (qPCR) methods targeting the REP-529 gene, as well as genotyping using GRA6 target genes, and (4) assessing the sensitivity and specificity of the nPCR and qPCR tests.
Out of 100 pregnant women screened, 70 were between the ages of 31 to 40 years old. Among them, 23 and 44 had one and two previous pregnancies. Additionally, 13 and 8 women had one and two history of abortions, respectively. Following serologic testing, 52% of the individuals were positive for T. gondii antibodies. Of these, 52 samples were positive for IgG antibodies, and one sample was positive for both IgG and IgM antibodies. Notably, all 52 cases with IgG positivity exhibited a high level of IgG avidity. Regarding the molecular testing of amniotic fluid samples, two pregnant women tested positive in the nPCR assay, while three tested positive in the qPCR assay. Furthermore, genotyping revealed that all positive samples belonged to type I of the T. gondii genotype. Moreover, none of the 100 buffy coat and urine samples tested positive for T. gondii using the nPCR and qPCR techniques.
The findings of the current study suggest that serological methods alone may not be reliable in diagnosing congenital toxoplasmosis and cannot rule out the diagnosis of toxoplasmosis and must be approved by molecular tests.
弓形虫病是一种常见的寄生虫感染，主要由刚地弓形虫（Toxoplasma gondii，T. gondii）引起。这种感染对孕妇中的新生儿和免疫功能受损的个体构成重大威胁。因此，开发一种新的诊断方法至关重要，该方法应具有高灵敏度和低风险采样的特点，以有效地管理患者。本研究的目的是利用血清学和分子技术对伊朗北部马赞达兰省接受羊膜穿刺术的 100 名孕妇进行弓形虫感染的诊断。
在怀孕 15-19 周期间，从马赞达兰省接受羊膜穿刺术的孕妇候选人中同时采集了 100 份羊水、血白细胞、血浆和尿液样本。本研究进行了以下评估：（1）通过化学发光法检测血浆中的抗 T. gondii IgM 和 IgG；（2）使用酶联免疫吸附试验技术（Enzyme-linked immunosorbent assay，ELISA）测定血浆中 IgG 的亲和力；（3）使用巢式 PCR（nPCR）和针对 REP-529 基因的定量实时 PCR（qPCR）方法，以及使用 GRA6 靶基因进行基因分型，检测羊水、血白细胞和尿液中的 T. gondii DNA；（4）评估 nPCR 和 qPCR 检测的灵敏度和特异性。
在筛查的 100 名孕妇中，有 70 名年龄在 31-40 岁之间。其中，23 名和 44 名分别有一次和两次妊娠史。此外，13 名和 8 名女性分别有一次和两次流产史。血清学检测后，有 52%的个体呈 T. gondii 抗体阳性。其中，52 个 IgG 抗体阳性样本，1 个 IgG 和 IgM 抗体均阳性样本。值得注意的是，所有 IgG 阳性的 52 例均表现出高 IgG 亲和力。关于羊水样本的分子检测，nPCR 检测有两例孕妇呈阳性，qPCR 检测有三例孕妇呈阳性。此外，基因分型显示所有阳性样本均属于 T. gondii 基因型 I。此外，nPCR 和 qPCR 技术均未检测到 100 例血白细胞和尿液样本中的 T. gondii。
本研究结果表明，单纯的血清学方法可能不可靠，无法诊断先天性弓形虫病，不能排除弓形虫病的诊断，必须经分子检测证实。
