Abstract
The recently emergent disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), transmitted by droplets and aerosols, was named coronavirus disease 2019 (COVID-19) by World Health Organization. Predominantly, the disease progress is asymptomatic or mild, but one-fifth of the patients advance to severe or critical illness. In severe COVID-19 patients, type-2 T helper cells release numerous cytokines; this excessive immune response is named as cytokine storm. The cytokine storm, which is the hallmark of the COVID-19 induced by the disease and aggravates due to lack of proper immune response, similar to SARS and Middle East respiratory syndrome (MERS), and the disease status may progress forward to acute respiratory distress syndrome (ARDS), systemic inflammatory response syndrome, multi-organ dysfunction syndrome, and death. Mesenchymal stromal cell transplantation is up-and-coming in treating many diseases such as HIV, hepatitis B, influenza, coronavirus diseases (SARS, MERS), lung injuries, and ARDS. Upon closer inspection on respiratory diseases, COVID-19, influenza, SARS, and MERS have similarities in pathogenesis, especially cytokine and immune response profiles. These comparable features in terms of the cytokine storm will provide hints for the treatment of COVID-19.