The Role of Interleukin-6 in the Pathogenesis, Prognosis and Treatment of Severe COVID-19

A newly identified virus appeared in Wuhan, China, in December 2019, was named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and caused the coronavirus disease 2019 (COVID-19). SARS-CoV-2 presents similarities with two pre-vious coronavirus pandemics, MERS (Middle East Respiratory Syndrome) and SARS-CoV, concerning phylogenetic origin, structural composition, and clinical symptoms, thus, leading to common pathogenic mechanisms. The purpose of this review is to de-clare the role of interleukin-6 (IL-6) in the pathogenesis, prognosis, and treatment of COVID-19 by comparing its effect on SARS-CoV and MERS cases. Increased levels of IL-6 comprise the key for the stimulation of cytokine storm and the progression of SARS, MERS, and COVID-19 cases. Especially, in COVID-19 patients, the overactiva-tion of NF-k Beta, which is caused by the binding of coronavirus spike protein S to alveolar epithelial cells, up-regulates IL-6 and promotes its systematic circulation, causing alveo-lar damage and extrapulmonary injury. Additionally, IL-6 can be used to evaluate respira-tory failure and identify asymptomatic patients. Tocilizumab (TCZ), a monoclonal anti-body which blocks IL-6 signaling, comprises a remedial option against COVID-19. TCZ improves oxygenation, reduces fever, and decreases levels of IL-6. IL-6 plays a major role in the pathogenesis of cytokine storm and the progression of COVID-19 and may be used as a therapeutic target against COVID-19. However, further research is needed con-cerning the relation of IL-6 in COVID-19 cases, and more clinical trials are required to declare TCZ as a treatment option.

Automated summary

The newly identified virus SARS-CoV-2 caused the COVID-19 pandemic, showing similarities with MERS and SARS. IL-6 plays a key role in the pathogenesis and treatment of COVID-19, with TCZ being a viable therapeutic option.