The clinical course and its correlated immune status in COVID-19 pneumonia

OBJECTIVES: To explore the clinical course and its dynamic features of immune status in COVID-19 patients and find predictors correlated with severity and prognosis of COVID-19. METHODS: The electronic medical records of 204 patients with COVID-19 pneumonia confirmed by nucleic acid testing were retrospectively collected and analyzed. RESULTS: All patients were divided into severe (69) and non-severe group (135). Lymphocyte subsets count, including CD3(+) T cell, CD4(+) T cell, CD8(+) T cell, B cell (CD19(+)) and NK cell (CD16(+) 56(+)), were significantly lower in severe group (P＜0.001). The dynamic levels of T lymphocyte in severe group were significantly lower from disease onset, but in the improved subgroup the value of T lymphocyte began to increase after about 15-day treatment and finally returned to the normal level. The cut-off value of the counts of CD3(+) (576), CD4(+) (391) and CD8(+) (214) T cell were calculated and indicated significantly high sensitivity and specificity for severity of COVID-19. CONCLUSION: Our results shown that the decrease of CD3(+), CD4(+) and CD8(+) T lymphocyte correlated with the course of patients with COVID-19 pneumonia, especially in severe cases. The level of T lymphocyte could be used as an indicator for prediction of severity and prognosis of patients with COVID-19 pneumonia. The application of glucocorticoid should be cautious in severe cases.