Critical appraisal of the “cytokine storm” concept in new coronavirus disease COVID-19. Review

Introduction. Novel coronavirus infection (COVID-19) is characterized by systemic hyper-inflammation with elevated inflammatory cytokines referred to cytokine storm. It has been recognized as a leading cause of severe COVID-19 and its progression to multi-organ failure. Objectives. To make a synthesis if the literature sources and to critical appraise “cytokine storm” concept in COVID-19. Results. While comparisons have been made between COVID-19 cytokine storm and other kinds of cytokine storm such as hemophagocytic lymphohistiocytosis and cytokine release syndrome, the pathogenesis of cytokine storm has not been clearly elucidated yet. Furthermore, many clinical evidences have indicated the importance of anti-inflammatory immunomodulation therapy in severe COVID-19. Although a number of studies have been conducted on target immunomodulatory therapy for severe COVID-19, no specific recommendations have been made yet. Moreover, there are some evidence against cytokine storm as pivotal pathogenetic mechanism for clinical deterioration in COVID-19 patients. Conclusion. There are enough evidence supporting cytokine response impairment as one of leading cause of COVID-19 progression to multiorgan failure. However, cytokine response abnormalities couldn’t explain clinical deterioration in some patients, so further studies are needed to find possible alternative pathogenetic mechanisms.