The role of interleukin-6 in monitoring severe case of coronavirus disease 2019

Progression to severe disease is a difficult problem in treating coronavirus disease 2019 (COVID-19). The purpose of this study is to explore changes in markers of severe disease in COVID-19 patients. Sixty-nine severe COVID-19 patients were included. Patients with severe disease showed significant lymphocytopenia. Elevated level of lactate dehydrogenase (LDH), C-reactive protein (CRP), ferritin, and D-dimer was found in most severe cases. Baseline interleukin-6 (IL-6) was found to be associated with COVID-19 severity. Indeed, the significant increase of baseline IL-6 was positively correlated with the maximal body temperature during hospitalization and with the increased baseline of CRP, LDH, ferritin, and D-dimer. High baseline IL-6 was also associated with more progressed chest computed tomography (CT) findings. Significant decrease in IL-6 and improved CT assessment was found in patients during recovery, while IL-6 was further increased in exacerbated patients. Collectively, our results suggest that the dynamic change in IL-6 can be used as a marker for disease monitoring in patients with severe COVID-19.