IL6 and COVID-19: Although some biomarkers, such as lymphocyte count, D-dimer, and interleukin (IL)-6, have been reported as risk factors for the severity of COVID-19 infection, most of these biomarkers can be used to distinguish patients with severe disease from normal persons or patients with mild disease 8; however, estimation of risk factors for COVID-19 disease progression in previous studies is not very robust.