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 previous coronavirus pandemics,
MERS (Middle East Respiratory Syndrome) and SARSCoV, concerning phylogenetic origin, structural composition, and clinical symptoms, thus, leading to common pathogenic mechanisms. The purpose of this review is to declare 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 overactivation of NF-kΒ, 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 alveolar damage and extrapulmonary injury. Additionally,
IL-6 can be used to evaluate
respiratory failure and identify asymptomatic patients.
Tocilizumab (TCZ), a
monoclonal antibody 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 concerning the relation of
IL-6 in
COVID-19 cases, and more clinical trials are required to declare TCZ as a treatment option.