IL6 and COVID-19: As a reference for pathologic upregulation of cytokines in serum, a predictive marker for respiratory failure in COVID-19 patients include serum levels of IL-6 greater than >80 pg mL-1 and C-reactive protein (CRP) >97 mg L-1 (34–36); peak levels of TA99-Neo2/15 serum IL-6 are in excess of 100 pg mL-1.