Etiological and immunopathogenetic aspects of multiorgan failure development in coronavirus disease (COVID-19)

The COVID-19 epidemic has already come to be seen as an emergency of international concern. This relates not only to the wide occurrence of the infection, but also to a fairly high mortality rate, currently more than 6.5 million deaths in the world. The aim of this study was to analyze, generalize and systematize the currently available literary data on the study of the novel coronavirus infection pathogenesis in the human body and to determine key changes that occur after the SARS-CoV-2 penetration into cells. In this way to target physicians primarily based on the pathogenetic processes that occur in the human body, syndromes and symptom complexes that are observed in treatments. Results. The article presents a literature review demonstrating that the specific interaction between the virus and somatic cells is the triggering mechanism for the pathogenesis of coronavirus infection. The main route for SARS-CoV-2 entry into the body is the angiotensin-converting enzyme 2 (ACE2) receptor, which is expressed not only in type 2 alveolar epithelial cells, but also in cells of the kidney, heart, blood vessels and gastrointestinal tract, including endotheliocytes and pericytes. Expression of the ACE2 receptor has also been shown in various structures and parts of the brain, cells of the conjunctiva, limbus, cornea and cells of the substantia propria. A high expression of the ACE2 receptor has been found in the epithelial cells of the oral mucosa, salivary glands, tonsils and tongue. These factors explain a possible involvement of different organs and systems in the development of multiorgan failure. Conclusions. In the development of multiorgan disfunction, two components are important: first, direct cell tropism and viral load, that may be unique in each patient. Secondly, it is the development of immune-mediated reactions to infected cells. Under conditions of hyperimmune inflammation, that is, the development of cytokine storm, acute respiratory distress syndrome progresses, and multiple organ failure develops. Endothelial damage is directly involved in the pathophysiology of this process, that results in the development of endothelial dysfunction, disruption of microcirculation, as well as perivascular inflammation, which aggravates damage to the endothelium and can lead to thrombus formation. The use of modern knowledge about the immunopathogenesis of COVID-19 would help to estimate the risk for severe infection and the possible development of complications, allowing for the timely implementation of effective pathogenetic therapy.