Xu et al. [37] treated 21 severe or critical COVID-19 patients with tocilizumab with routine therapy: fever ceased in all patients; 15 patients lowered their oxygen demand within 5 days after tocilizumab administration; C-reactive protein (CRP) levels decreased significantly in most patients; Computed tomography (CT) showed improvement of the lung opacities. Here, CRP is linked to COVID-19.