Remesar Mirta C, Sabino Ester C, Buss Lewis F, Merlo Claudio D, López Mónica G, Humeres Sebastián L, Pavón Héctor A, Di Germanio Clara, Coco Sonia Bakkour, Oliveira-da Silva Léa C, Martins Pinto Filho Marcelo, Ribeiro Antonio L, Busch Michael P, Del Pozo Ana E
Centro Regional de Hemoterapia Garrahan, Hospital de Pediatría Prof. Dr. J. P. Garrahan, Ciudad de Buenos Aires, Buenos Aires, Argentina.
Laboratório de Parasitología Medica (LIM-46), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil.
PLoS Negl Trop Dis. 2025 May 30;19(5):e0012724. doi: 10.1371/journal.pntd.0012724. eCollection 2025 May.
In our previous study of blood donors in the Argentinian Chaco Province, we documented bimodal distributions of anti-Trypanosoma cruzi antibody (Ab) levels, suggesting potential self-cure in donors with low-reactive samples. This study aimed to correlate "high" and "low" Ab level groups, defined by a mathematical model, with parasitemia and electrocardiogram findings. Ab decline over time was also assessed.
METHODOLOGY/ PRINCIPAL FINDINGS: We invited T. cruzi Ab reactive blood donors to enroll in the study from October 2018 to November 2019 with a follow up visit two years later. Blood samples were tested for T cruzi Ab by: Chagatest ELISA Lisado and Chagatest ELISA Recombinante v.4.0 (Wiener Lab, Argentina); VITROS Immunodiagnostic Products Anti-T.cruzi (Chagas) (Ortho-Clinical Diagnostics Inc., UK), and Architect Chagas (Abbott Laboratories, Germany). Target capture polymerase chain reaction (PCR) was performed on lysed whole blood samples from enrollment visits and electrocardiograms on second visits. Four hundred fifty donors were recruited, but 68 were excluded due to negative results on all study Ab assays. Ab level distributions were bimodal and classified as "high" or "low" at a calculated threshold for each of four assays. There were 160 donors with low and 179 with high Ab results on all assays. The remainder 43 were discordant reactive. Ninety-seven percentage of the PCR positive donors were among the concordant high Ab group. During the 2-4 year follow-up interval, relative Ab declines by three assays were significantly greater among those classified as low Ab and with negative PCR results.
CONCLUSIONS/ SIGNIFICANCE: Ab reactivity is associated with PCR-detectable parasitemia. Greater Ab declines were detected among donors with low and/or discordant Ab reactivity and negative PCR results, suggesting spontaneous parasite clearance in these donors.
在我们之前对阿根廷查科省献血者的研究中，我们记录了抗克氏锥虫抗体（Ab）水平的双峰分布，这表明反应性较低样本的献血者可能存在自愈情况。本研究旨在将通过数学模型定义的“高”和“低”Ab水平组与寄生虫血症和心电图结果相关联。还评估了Ab水平随时间的下降情况。
方法/主要发现：我们邀请克氏锥虫Ab反应性献血者于2018年10月至2019年11月参加本研究，并在两年后进行随访。通过以下方法检测血样中的克氏锥虫Ab：Chagatest ELISA Lisado和Chagatest ELISA Recombinante v.4.0（阿根廷维纳实验室）；VITROS免疫诊断产品抗克氏锥虫（恰加斯病）（英国奥瑟临床诊断公司），以及Architect恰加斯病检测（德国雅培实验室）。对入组时采集的全血样本进行靶标捕获聚合酶链反应（PCR），并在第二次就诊时进行心电图检查。招募了450名献血者，但由于所有研究Ab检测结果均为阴性，68人被排除。Ab水平分布呈双峰状，并根据四种检测方法各自计算出的阈值分为“高”或“低”。所有检测中，有160名献血者Ab结果为低，179名结果为高。其余43人反应不一致。97%的PCR阳性献血者在高Ab结果一致的组中。在2至4年的随访期间，三种检测方法中，归类为低Ab且PCR结果为阴性的献血者Ab相对下降幅度明显更大。
结论/意义：Ab反应性与PCR可检测到的寄生虫血症相关。在Ab反应性低和/或不一致且PCR结果为阴性的献血者中检测到更大的Ab下降，这表明这些献血者体内的寄生虫出现了自发清除。
