CXCL8 and immune system disorder: Both anti-inflammatory cytokines (such as IL-10 and IL-13) and pro-inflammatory cytokines (such as IL-1β, IL-6, IP-10, G-CSF, IL-8, IL-17 and IFN-γ) were significantly increased in COVID-19 patients, suggesting a serious immune disorder, which has been reported in other pathogenic coronaviruses (CoV) including Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV) (21, 23, 24).