Neutrophil functional activity indices as predictors of COVID-19 severity

Aschina L.A., Baranova N.I., Bolgova A.I.

Penza Institute for Further Training of Physicians – Branch Campus of the Federal State Budgetary Educational Institution of Further Professional Education «Russian Medical Academy of Continuing Professional Education» of the Ministry of Healthcare of the Russian Federation, Penza, RussiaState Budget Health Care Institution «Penza Regional Clinical Center of Specialized Types of Medical Care», Penza, Russia

COVID-19 is a respiratory disease caused by Sars-Cov-2, which can progress to acute respiratory distress syndrome (ARDS) and trigger immunopathological mechanisms leading to excessive inflammation and leukocyte dysfunction. Neutrophils are the earliest cells of the innate immune response in the infectious process, which play an important role in the pathogenesis of this disease. The aim of the study was to investigate the functional activity of neutrophils in COVID-19 patients depending on the severity degree. The study included 67 patients with COVID-19 which were divided into three groups (with mild, moderate, severe and extremely severe course). The parameters of 30 practically healthy people were used as a control. We identified changes in the kinetics of chemiluminescent response of neutrophils in patients with COVID-19, regardless of severity, consisting in reduced rates of spontaneous and induced production of ROS neutrophils, time to the maximum glow compared with healthy people, indicating a decrease in phagocytic activity of cells. Analysis of parameters of functional activity of neutrophils in groups of patients with different degrees of severity revealed that the values of spontaneous and induced production of ROS by cells were the lowest in patients with severe and extremely severe course, which conditioned the increase of immunodeficiency state. This can lead to the development of incomplete phagocytosis and progression of the pathological state in COVID-19. Significant decrease in the indicators of neutrophil functional activity in patients with this disease can be used as a predictor of COVID-19 severity.