Neutrophils and pregnancy-associated malaria

Abstract

Abstract Purpose: Pregnant women living in Sub-Sahara Africa (sSA) are exposed to malaria and its harmful consequences on pregnancy outcomes. Neutrophils are the most abundant white blood cells (WBC) in the bloodstream and are innate immune key effectors against infections. Substantial work has been done to study the role of neutrophils in malaria, but little on pregnancy-associated malaria (PAM). This review focuses on neutrophil responses to malaria during pregnancy that may help us to understand their dynamics and effects on pregnancy outcomes. Source: A literature review covering the topic of PAM and neutrophils were accessed via PubMedâ and Embaseâ databases. In total, 20 unique publications were found in PubMed while 99 in Embaseâ. After excluding 113 irrelevant titles and abstracts, 6 original articles full texts were assessed and included in this review. Results: Due to oestrogen stimulation, the number of neutrophils is higher in pregnant women compared to non-pregnant women. This increase in neutrophil numbers reaches a plateau in the second and third trimesters of pregnancy. However, the number of circulating neutrophils in peripheral blood is lower in pregnant women with Plasmodium falciparummalaria than in pregnant women without malaria. The decrease in circulating neutrophils in the context of PAM may reflect the accumulation of neutrophils in the infected placenta. Data showed that the prevalence of children with low birth weight (LBW) was higher in pregnant women with high number of pigmented peripheral neutrophils compared to malaria-infected pregnant women with low number of pigmented peripheral neutrophils. A case of Plasmodium vivaxexflagellated microgametes was described for the first time in pregnant woman neutrophils. Conclusions: This review aids our understanding of the dynamics of neutrophils during a malaria infection in in pregnant women by providing scientific evidence that suggests that neutrophil dynamics decrease in pregnant women with malaria infection. A negative association between the number of pigmented neutrophils in women with malaria and the birth weight of children points towards prioritizing future research in pregnant women with malaria on these cells involved in the first line of innate immunity.