CXCL8 and COVID-19: Mechanistic research shows that the abnormal characteristics of monocytes in elderly patients may be related to mitochondrial dysfunction in senescent monocytes.54 In addition, male patients infected with COVID-19 have more severe symptoms and suffered to the higher mortality rate than female patients because of the increased accumulation of non-classical monocytes in the peripheral blood and more secretions of IL-8 and IL-18.71 These monocytes reduced T-cell function to cause severe symptoms in male patients.