Interrelationships between polymorphonuclear leukocytes (PMNs)- neutrophils, blood coagulation system and vascular endothelium during Covid-19 infection

B. Bechev, S. Stoeff, K. Kavaldzhieva

Abstract: Background. Polymorphonuclear leukocytes (PMNs - neutrophils) influence the processes of inflammation and immunity, participating in phagocytosis, cytoplasmic degranulation, NETosis, generation of reactive oxygen species (ROS), receptor-mediated communications with other cells and systems, innate and adaptive immunity, blood coagulation- and circulatory systems, etc.
Neutrophils during development of Covid-19 disease. The participation of neutrophils during development, treatment and management of COVID-19 infection is evaluated and largely discussed in the scientific medical literature. The elevated neutrophil-to-lymphocyte ratio (NLR) and dynamic lowering of some routine blood parameters seem to be critical markers of severe COVID-19. Thus, dysregulation of immune system - with special participation of complement, leads to hyperproduction of cytokines and chemokines („cytokine storm”). The resulting pro-adhesive and prothrombotic effects stimulate further adhesion of leukocytes and platelets to the vascular endothelium, causing macro- and microvascular thromboses, capillary plugging and impaired microvascular flow.

Series on Biomechanics, Vol.36 No.1 (2022), 136-145
DOI: 10.7546/SB.18.2022

Keywords: blood coagulation system; COVID-19 infection; PMNs - neutrophils; SARS-CoV-2; vascular endothelium

Date published: 2022-04-12