Chukwuanukwu Rebecca Chinyelu, Agu Chioma Esther, Ehiaghe Alfred, Ezeagwuna Dorothy, Herrmann Martin, Udigwe Gerald
Immunology Department, Faculty of Medical Laboratory Science, Nnamdi Azikiwe University, Awka, Nigeria.
Department of Internal Medicine 3, Uniklinikum Erlangen, Erlangen and Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
BMC Immunol. 2025 Apr 8;26(1):28. doi: 10.1186/s12865-025-00709-4.
Neutrophils are the first responders to pathogen invasion and are important first-line defenders. The defence mechanism of activated neutrophils includes neutrophil extracellular traps (NETs) formation that immobilize pathogens, stop their spread within the tissues, and ultimately kill them. However, their roles in the context of malaria during pregnancy are still elusive. This study was conducted to investigate markers of neutrophil activation as well as immunological and haematological cellular responses during Plasmodium infection in pregnancy.
A total of 340 pregnant women aged between 19 and 42 years were recruited for this study carried out in South-east, Nigeria. All the subjects were tested for malaria parasite (MP) status. Those infected with human immunodeficiency virus (HIV) and those with any other co-morbidity were excluded from the study. A total of 45 (13.2%) of the 340 pregnant women were positive for malaria. To assess immune, haematologic and NETs markers in the MP positive group, 45 matched malaria-negative pregnant women from the malaria negative group served as controls. Thus, the final study population was grouped into two categories: 45 pregnant women infected with Plasmodium falciparum and 45 pregnant malaria-negative control group. The neutrophil elastase concentration, myeloperoxidase activity, total white blood cell counts, white blood cell differential counts, platelet counts and haematocrit were assessed via standard laboratory methods.
Findings from this study revealed lower levels of myeloperoxidase in the malaria- infected cohort (p = 0.013) than in the malaria negative cohort. The neutrophil elastase levels were also lower in the malaria negative group (p = 0.042). The total white blood cells, platelet and neutrophil counts were lower (p = 0.046, 0.012 and 0.015, respectively) in the malaria infected group when compared to the controls. Conversely, lymphocyte counts were higher in the malaria-infected group (p = 0.003). No cases with high parasitaemia were encountered among the pregnant women infected with Plasmodium falciparum.
Malaria infection led to alterations in immune and haematological parameters in this group, with mild and moderate malaria parasitaemia in the study cohort. Although there were some significant differences, the assessed values remained mostly within the normal range. Further studies in a larger cohort assessing pregnant women infected with placental malaria and those with fatal outcomes are important to further investigate the role of NETs in malaria infection.
中性粒细胞是病原体入侵的首批响应者，是重要的一线防御者。活化的中性粒细胞的防御机制包括形成中性粒细胞胞外陷阱（NETs），其可固定病原体，阻止其在组织内扩散，并最终将其杀死。然而，它们在妊娠期疟疾中的作用仍不清楚。本研究旨在调查妊娠期疟原虫感染期间中性粒细胞活化的标志物以及免疫和血液学细胞反应。
本研究在尼日利亚东南部进行，共招募了340名年龄在19至42岁之间的孕妇。所有受试者均接受疟原虫（MP）状态检测。感染人类免疫缺陷病毒（HIV）的孕妇以及患有任何其他合并症的孕妇被排除在研究之外。340名孕妇中共有45名（13.2%）疟疾检测呈阳性。为了评估MP阳性组中的免疫、血液学和NETs标志物，从疟疾阴性组中选取45名匹配的疟疾阴性孕妇作为对照。因此，最终的研究人群分为两类：45名感染恶性疟原虫的孕妇和45名疟疾阴性对照组孕妇。通过标准实验室方法评估中性粒细胞弹性蛋白酶浓度、髓过氧化物酶活性、白细胞总数、白细胞分类计数、血小板计数和血细胞比容。
本研究结果显示，疟疾感染队列中的髓过氧化物酶水平低于疟疾阴性队列（p = 0.013）。疟疾阴性组中的中性粒细胞弹性蛋白酶水平也较低（p = 0.042）。与对照组相比，疟疾感染组中的白细胞、血小板和中性粒细胞计数较低（分别为p = 0.046、0.012和0.015）。相反，疟疾感染组中的淋巴细胞计数较高（p = 0.003）。感染恶性疟原虫的孕妇中未出现高寄生虫血症病例。
疟疾感染导致该组免疫和血液学参数发生改变，研究队列中的疟疾寄生虫血症为轻度和中度。尽管存在一些显著差异，但评估值大多仍在正常范围内。对更大队列中感染胎盘疟疾的孕妇和有致命结局的孕妇进行进一步研究，对于进一步调查NETs在疟疾感染中的作用很重要。
