Data on positive mothers and newborns.

BackgroundChagas disease, once restricted mainly to the Americas, Chagas disease has become a global health problem due to migration from endemic to non-endemic areas. In non-endemic regions, transmission is limited to vertical transmission from infected mothers to newborns or through blood and organ donations. A major challenge in the management of the disease lies in the diagnosis of chronic cases, as blood-borne parasites are often absent and antibodies persist for life, complicating the evaluation of treatment.Methodology and main findingsThis study investigates whether detection of circulating extracellular vesicles (EVs) or their immunocomplexes with host IgGs in the serum of chronic patients with Chagas disease could serve as diagnostic tools and biomarkers of the active presence of the parasite. This method may prove valuable in cases where parasitaemia and other diagnostic tests are inconclusive, especially for assessing treatment efficacy and confirming mother-to-child transmission. Together with exovesicle purification by ultracentrifugation, which is the ‘gold standard’, an affordable and simplified method for the isolation of EVs or immunocomplexes was tested for use in less well-equipped diagnostic laboratories.EV detection was performed by enzyme-linked immunosorbent assay (ELISA) targeting Trypanosoma cruzi antigens. Positive results were demonstrated in Bolivian patients in Spain, covering asymptomatic and symptomatic cases (cardiac, gastrointestinal or both). The study also examined infected mothers and their newborns. These findings were further confirmed in Panamanian patients with inconclusive diagnostic results.Moreover, host IgG isotypes that formed immunocomplexes with parasite exovsicles were identified, with IgG2 and IgG4 being predominant.ConclusionsOur results confirm the usefulness of circulating EVs and their immunocomplexes as markers of metabolically active T. cruzi in chronic infections without detectable parasitaemia, as well as their efficacy in confirming vertical transmission and in cases of inconclusive diagnostic tests.研究背景 恰加斯病（Chagas disease）曾主要局限于美洲地区，但由于流行区人群向非流行区迁徙，现已成为全球性公共卫生问题。在非流行区域，其传播途径仅局限于受感染母亲向新生儿的垂直传播，或经由血液与器官移植传播。该病诊疗面临的一大挑战在于慢性病例的诊断：血液中往往无法检出寄生虫，但抗体却会终身留存，这使得治疗效果评估变得复杂。 研究方法与主要发现 本研究旨在探讨：在恰加斯病慢性患者的血清中，检测循环细胞外囊泡（extracellular vesicles, EVs）及其与宿主IgG形成的免疫复合物，能否作为寄生虫活跃存在的诊断工具与生物标志物。该方法在寄生虫血症及其他诊断结果不明确的病例中具有应用价值，尤其适用于治疗效果评估与母婴传播确认场景。本研究以超速离心法（该方法为外囊泡纯化的金标准）作为对照，同时测试了一种低成本、易操作的细胞外囊泡或免疫复合物分离方法，以供设备条件有限的诊断实验室使用。 研究采用针对克氏锥虫（Trypanosoma cruzi）抗原的酶联免疫吸附试验（enzyme-linked immunosorbent assay, ELISA）进行细胞外囊泡检测。在西班牙的玻利维亚裔患者中检测出阳性结果，涵盖无症状与有症状病例（包括心脏型、胃肠道型或二者兼具的病例）。研究同时对受感染母亲及其新生儿进行了检测。上述发现在诊断结果不明确的巴拿马裔患者中得到了进一步验证。此外，研究还鉴定出了与寄生虫外囊泡形成免疫复合物的宿主IgG亚型，其中以IgG2与IgG4为主。 研究结论 本研究结果证实，循环细胞外囊泡及其免疫复合物可作为无法检出寄生虫血症的慢性恰加斯病患者体内克氏锥虫代谢活跃的标志物，同时也可用于确认垂直传播以及诊断结果不明确的病例的检测。