Thromboinflammation response to tocilizumab in COVID-19

Background Coronavirus disease-19 (COVID-19) spans a wide spectrum of illness. Severe cases of COVID-19 can manifest inflammation in organs other than the lung, in tissues not known to support viral replication, and also in a hypercoagulable state. These observations have suggested that severe acute respiratory syndrome coronavirus 2 can provoke a hyperimmune response in some cases that could lead to secondary organ damage. Methods With evidence of elevated levels of interleukin-6 (IL-6) in patients with severe COVID-19, we conducted a small pilot off-label compassionate care study of the IL-6 receptor inhibitor tocilizumab in patients with severe COVID-19. Results A single infusion of tocilizumab in patients with severe COVID-19 manifested rapid declines in C-reactive protein andd-dimer and gradual rises in lymphocyte and platelet counts. Conclusions These findings suggest both pathophysiological mechanisms and clinical benefit that might be seen with IL-6 inhibition in severe COVID-19.