IL6 and COVID-19: Recently, many researchers are focused on the application of cytokine-based interventions, including immune inhibitors (such as inhibitors of IL-6, IFN-γ and TNF-α) in the therapy of COVID-19, and some of these inhibitors showed enthusiastic results (such as IL-6 inhibitor, siltuximab) [90, 91], however, more studies are needed to further investigate the therapeutic effects of these inhibitors.