Laboratório de Epidemiologia de Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil.
Pós-graduação em Ciências da Saúde, Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Brazil.
Parasitology. 2020 Sep;147(10):1124-1132. doi: 10.1017/S0031182020000852. Epub 2020 May 28.
In areas endemic for Leishmania infantum, an asymptomatic infection may be an indicator of the extent of transmission. The main goal of this study was to evaluate the applicability of measuring circulating immunological biomarkers as an alternative strategy to characterize and monitor L. infantum asymptomatic infections in combination with serological methods. To this end, 179 children from a region endemic for visceral leishmaniasis (VL), aged 1-10 years old, selected from a cross-sectional study, were identified as asymptomatic (n = 81) or uninfected (n = 98) by qPCR and/or serological tests (ELISA using L. infantum soluble antigen and rK39), and, together with serum samples of children diagnosed with VL (n = 43), were subjected to avidity tests and cytokine levels measurement. Avidity rates (AR) ranging from 41 to 70% were found in 29 children (66%) from the asymptomatic group. On the other hand, high AR (above 70%) were observed in 27 children (64%) from the VL group. Logistic Regression and Classification and Regression Tree (CART) analyses demonstrated that lower AR and IFN-γ production associated with higher IL-17A levels were hallmarks in asymptomatic L. infantum infections. Therefore, this study proposes an association of immunological biomarkers that can be used as a complementary strategy for the characterization and monitoring of asymptomatic VL infections in children living in endemic areas.
在利什曼原虫地方性流行地区，无症状感染可能是传播程度的一个指标。本研究的主要目的是评估测量循环免疫生物标志物作为一种替代策略的适用性，以结合血清学方法来描述和监测利什曼原虫无症状感染。为此，从一项横断面研究中选择了来自内脏利什曼病（VL）地方性流行地区的 179 名年龄在 1-10 岁的儿童，通过 qPCR 和/或血清学检测（使用利什曼原虫可溶性抗原和 rK39 的 ELISA）将其确定为无症状（n=81）或未感染（n=98），并与确诊为 VL 的儿童的血清样本（n=43）一起进行亲和力检测和细胞因子水平测量。在无症状组的 29 名儿童（66%）中发现了 41-70%的亲和力率（AR）。另一方面，在 VL 组的 27 名儿童（64%）中观察到了高 AR（超过 70%）。逻辑回归和分类回归树（CART）分析表明，无症状利什曼原虫感染的特征是较低的 AR 和 IFN-γ产生与较高的 IL-17A 水平相关。因此，本研究提出了一种免疫生物标志物的关联，可作为描述和监测地方性流行地区儿童无症状 VL 感染的一种补充策略。
