Direct blood fluorescence signal intensity of neutrophils (NEU-SFL): A marker of NETosis in preeclampsia?

Preeclampsia (PE) is associated with high maternal and foetal morbidity and mortality. Several studies have shown that plasma nucleosomes, cell-free DNAs and citrullinated histone H3 (CitH3) increased during pregnancy, and that their levels were even higher in PE [ [1] Bouvier S. Mousty E. Fortier M. Demattei C. Mercier E. Nouvellon E. Chea M. Grosjean F. Letouzey V. Gris J.C. Placenta-mediated complications: nucleosomes and free DNA concentrations differ depending on subtypes. J. Thromb. Haemost. 2020; 18: 3371-3380 Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar ]. In vitro, some recombinant histones, particularly histone H3, affected migration, invasion and induced apoptosis of extravillous trophoblasts [ [2] Bouvier S. Fortier M. Vincent L. Demattei C. Mousty E. Herzog M. Rommelaere G. Nouvellon E. Mercier E. Letouzey V. Gris J.C. NETosis markers in pregnancy: effects differ according to histone subtypes. Thromb. Haemost. 2021; https://doi.org/10.1055/s-0040-1722225 Crossref PubMed Scopus (6) Google Scholar ]. Nucleosomes are key components of neutrophil extracellular traps (NETs) which are released by polymorphonuclear neutrophils (PMNs) activation, a process called NETosis. Aberrant NETosis has been described in PE [ [3] Hahn S. Giaglis S. Hoesli I. Hasler P. Neutrophil NETs in reproduction: from infertility to preeclampsia and the possibility of fetal loss. Front. Immunol. 2012; 3: 362 Crossref PubMed Scopus (93) Google Scholar ].