A novel virus, SARS-CoV-2, emerged in Wuhan in December 2019 and rapidly spread to other cities in China and other countries. Several studies have summarized the clinical characteristics and laboratory findings of patients with Corona Virus Disease 2019 (COVID-19) (1, 2). According to these studies, in addition to lung injury, damages involving other organs, which include liver, kidney, heart, and hemopoietic system, were also observed in some patients, suggesting the presence of systemic inflammation, and from the work by Huang et al. (1), we noted that elevation of various proinflammatory cytokines was present in patients infected with SARS-CoV-2, suggesting the possible existence of cytokine storm in a proportion of patients. Further, patients that require intensive care unit (ICU) admission showed higher concentrations of certain cytokines compared with those not requiring ICU admission, indicating that the levels of proinflammatory cytokines were associated with disease severity. Further studies confirmed that levels of cytokines including interleukin (IL)-6 and IL-8 correlated with the disease severity of COVID-19 (3, 4). This phenomenon is not restricted to COVID-19, in the previous studies regarding the Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), higher levels of certain cytokines were associated with increased mortality (5, 6). For instance, high IL-6 concentration predicted mortality in patients with MERS (5). In patients infected with pathogenic human coronaviruses, cytokine storm contributes to acute lung injury and acute respiratory distress syndrome (ARDS) (7). Therefore, controlling the cytokine storm might be a strategy for treating patients with COVID-19, especially for those severe cases.