ObjectiveTo investigate the characteristics and prognostic value of cellular immune function in severe patients with coronavirus disease 2019 (COVID-19).MethodsA cohort study was conducted to collect the clinical data of 119 severe patients admitted to the Renmin Hospital of Wuhan University (Eastern District) including 60 males (50.4%) and 59 females (49.6%), with an average age of 60.9±14.2 years. The primary endpoint of follow-up was death in the hospital, and the disease outcome classification was the secondary endpoint of follow-up within 30 days after admission. We analyzed the correlation between cellular immune function and COVID-19 prognosis.Results A total of 22 patients died during this process, and 47 patients were severe/critical during the follow-up period. The counts of CD3+, CD4+, CD8+, and CD19+ in the primary endpoint events were significantly different between the survival group and the death group (all P<0.05). The counts of CD3+, CD4+, CD8+, CD19+ in the secondary endpoint events were significantly different between the normal group and the severe/critical group (all P<0.05). The results of the receiver operating characteristic (ROC) curve showed that the area under the cellular immune function curve of dead patients and severe/critical patients had good predictive value (all P<0.05).ConclusionCell immune function has good clinical and prognostic value for COVID-19.