Abstract：
BACKGROUND: The mechanisms that mediate immune protection in individuals with subclinical (SC) or asymptomatic infection with L. braziliensis are largely unknown. Neutrophils (PMNs) have been implicated in progressive symptomatic cutaneous leishmaniasis (CL), but their potential participation in maintenance of subclinical infection is unexplored. The aim of this study was to compare the phenotypic and functional profiles of PMNs in individuals with SC infection versus patients with symptomatic CL due to L. braziliensis.
METHODS: Subjects were recruited in the endemic region of Corte de Pedra, Bahia, Brazil. Surface markers to define activation status were characterized by flow cytometry. Functional responses of PMNs including phagocytic capacity, production of oxidative species, and oxidative killing of intracellular parasites were studied in vitro.
RESULTS: PMNs from individuals with SC infection displayed a more activated phenotype and greater ability to control the infection than PMNs from patients with CL. In contrast, PMNs from patients with CL exhibited higher expression of HLA-DR and higher production of oxidative species than PMNs from subjects with SC infection.
CONCLUSIONS: PMNs from individuals with SC infection can control the infection more efficiently than PMNs from patients with CL, despite the lower production of oxidants. Our observations suggest that L. braziliensis may evade microbicidal mechanisms of PMNs from patients with CL, contributing to parasite dissemination and the establishment of disease.
METHODS: Subjects were recruited in the endemic region of Corte de Pedra, Bahia, Brazil. Surface markers to define activation status were characterized by flow cytometry. Functional responses of PMNs including phagocytic capacity, production of oxidative species, and oxidative killing of intracellular parasites were studied in vitro.
RESULTS: PMNs from individuals with SC infection displayed a more activated phenotype and greater ability to control the infection than PMNs from patients with CL. In contrast, PMNs from patients with CL exhibited higher expression of HLA-DR and higher production of oxidative species than PMNs from subjects with SC infection.
CONCLUSIONS: PMNs from individuals with SC infection can control the infection more efficiently than PMNs from patients with CL, despite the lower production of oxidants. Our observations suggest that L. braziliensis may evade microbicidal mechanisms of PMNs from patients with CL, contributing to parasite dissemination and the establishment of disease.
摘要：
背景：在亚临床（SC）或无症状感染巴西乳杆菌的个体中介导免疫保护的机制在很大程度上是未知的。中性粒细胞（PMNs）与进行性症状性皮肤利什曼病（CL）有关，但它们在维持亚临床感染方面的潜在参与尚未被探索。这项研究的目的是比较SC感染患者与由于巴西乳杆菌引起的有症状CL患者的PMN的表型和功能特征。
方法：受试者在CortedePedra流行区招募，巴伊亚,巴西。通过流式细胞术表征定义活化状态的表面标志物。PMN的功能反应，包括吞噬能力，氧化物质的产生，体外研究了细胞内寄生虫的氧化杀伤作用。
结果：来自SC感染个体的PMN比来自CL患者的PMN表现出更活化的表型和更强的控制感染的能力。相比之下,与SC感染受试者的PMN相比，CL患者的PMN表现出更高的HLA-DR表达和更高的氧化物质产生。
结论：来自SC感染个体的PMNs比来自CL患者的PMNs更有效地控制感染，尽管氧化剂的产量较低。我们的观察结果表明，巴西乳杆菌可能会逃避CL患者PMN的杀菌机制，有助于寄生虫传播和疾病的建立。
方法：受试者在CortedePedra流行区招募，巴伊亚,巴西。通过流式细胞术表征定义活化状态的表面标志物。PMN的功能反应，包括吞噬能力，氧化物质的产生，体外研究了细胞内寄生虫的氧化杀伤作用。
结果：来自SC感染个体的PMN比来自CL患者的PMN表现出更活化的表型和更强的控制感染的能力。相比之下,与SC感染受试者的PMN相比，CL患者的PMN表现出更高的HLA-DR表达和更高的氧化物质产生。
结论：来自SC感染个体的PMNs比来自CL患者的PMNs更有效地控制感染，尽管氧化剂的产量较低。我们的观察结果表明，巴西乳杆菌可能会逃避CL患者PMN的杀菌机制，有助于寄生虫传播和疾病的建立。
