IL6 and COVID-19: Auxiliary markers that predict severe COVID-19 are as follows: (1) progressive decline in peripheral blood lymphocyte count; (2) progressive elevation in peripheral blood inflammatory factors such as IL-6 and the C-reactive protein; (3) progressive elevation in lactic acid level; (4) and imaging results showing bilateral or multilobar infiltration, pleural effusion, or short-term increase in lesions (32, 33).