Post-COVID immunopatology syndrome: characteristics of phenotypical changes in the immune system in post-COVID patients

Abstract

This study examines the long-term effects of SARS-CoV-2 infection on immune status. Given the prolonged and profound immune dysregulation observed during acute SARS-CoV-2 infection, it remains to be determined whether these changes translate into subsequent immune system dysfunction in recovering individuals. In this sense, the aim of the study was to study the parameters of the immune system in patients who had undergone SARS-CoV-2 infection. 150 patients who underwent SARS-CoV-2 infection were examined according to 96 parameters using flow cytometry. A complete blood count was performed using a Medonic device (Sweden); ELISA method determined the levels of general and specific IgM, IgG, IgA, compliment fragments (JSC Vector-Best, Russia). The activity of the phagocytes was studied according to the generally accepted method. The study found that at least four phenotypes of immune system disorders are detected in patients. The first two phenotypes are related to the impairment of innate immune system factors and are associated with a decrease in the number of CD46+ and NK cells. It has been observed that a decrease in CD46+ persists for a long time in a significant number of recovered patients, highlighted by the impaired expression of this marker in various subpopulations of lymphocytes. The decrease in the level of natural killers was accompanied by a compensatory increase in the number of T lymphocytes, mainly due to T helpers and TNK lymphocytes, and the growth of total memory B cells. Two other identified phenotypes are characterized by damage to acquired immune response factors and are associated with damage to B cells and T cytotoxic cells. The relationship of such disorders with damage to hematopoiesis erythrocyte and platelet sprouts, which contribute to the appearance of hypoxia and possible violation of the blood coagulation system, has been shown. Therefore, the results obtained indicate a long-term pronounced damage to the immune system in postCOVID patients that requires immunocorrection of these disorders.