Mortality of COVID-19 is Associated with Cellular Immune Function Compared to Immune Function in Chinese Han Population

In December 2019, novel coronavirus (SARS-CoV-2) infected pneumonia occurred in Wuhan, China. The number of cases has increased rapidly but information on the clinical characteristics of SARS-CoV-2 pneumonia compared to normal controls in Chinese Han population is limited. Our objective is to describe the clinical characteristics of SARS-CoV-2 pneumonia compared to normal controls in the Chinese Han population. In this case series of 752 patients, the full spectrum of cases is described. Fever was present in 86-90% of the patients. The second most common symptom was cough (49.1-51.0%), fatigue (25.2-27.1%), sputum (20.0-23.1%), and headache (9.8-11.1%). the mortality rate is 4.6% in Wuhan, 1.9% in Beijing, and 0.9% in Shanghai. Our findings showed that the levels of lymphocytes were 0.8（IQR, 0.6-1.1）109/L in Wuhan, 1.0（IQR, 0.7-1.4）109/L in Beijing, and 1.1 (IQR, 0.8-1.5) 109/L in Shanghai before admission to hospitals, respectively, indicating that cellular immune function might relate to the mortality. Based on the reference ranges of normal Chinese Han population and the data of the critically ill patients we have observed, it is recommended that reference ranges of people at high risk of COVID-19 infection are CD3+ lymphocytes below 900 cells/mm3, CD4+ lymphocytes below 500 cells/mm3, and CD8+ lymphocytes below 300 cells/mm3.