An enlightening role for cytokine storm in coronavirus infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in Wuhan, China has dispersed rapidly worldwide. Although most patients present with mild fever, cough with varying pulmonary shadows, a significant portion still develops severe respiratory dysfunction. And these severe cases are often associated with manifestations outside the respiratory tract. Currently, it is not difficult to find inflammatory cytokines upregulated in the blood of infected patients. However, some complications in addition to respiratory system with the coronavirus disease 2019 (COVID-19) are impossible to explain or cannot be attributed to virus itself. Thus excessive cytokines and their potentially fatal adverse effects are probably the answer to the multiple organ dysfunctions and growing mortality. This review provides a comprehensive overview of the mechanisms underlying cytokine storm, summarizes its pathophysiology and improves understanding of cytokine storm associated with coronavirus infections by comparing SARS-CoV-2 with severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV).