Using IL-2R/lymphocyte for predicting the clinical progression of patients with COVID-19.

Effective laboratory markers for estimation of disease severity and predicting the clinical progression of coronavirus disease-2019 (COVID-19) is urgent needed.The laboratory tests including blood routine, cytokine profiles and infection markers were collected from 389 confirmed COVID-19 patients.The included patients were classified into mild (n=168), severe (n=169) and critical groups (n=52). The leukocytes, neutrophils, infection biomarkers (such as CRP, PCT and ferritin) and the concentrations of cytokines (IL-2R, IL-6, IL-8, IL-10 and TNF-α) were significantly increased while lymphocytes were significantly decreased with increased severity of illness. The amounts of IL-2R was positively correlated with the other cytokines and negatively correlated with lymphocyte number. The ratio of IL-2R to lymphocytes was found remarkably increased in severe and critical patients. IL-2R/lymphocyte was superior compared with other markers for the identification of COVID-19 with critical illness not only from mild but also from severe illness. Moreover, the cytokine profiles and IL-2R/lymphocyte were significantly decreased in recovered patients but further increased in disease deteriorated patients, which might be correlated with the outcome of COVID-19.Lymphopenia and increased levels of cytokines were closely associated with the disease severity. IL-2R/lymphocyte was a prominent biomarker for early identification of severe COVID-19 and predicting the clinical progression of the disease.