Dynamic Characteristics of Lymphocyte Subsets and Their Predictive Value for Disease Progression and Prognosis in Primary Infection and Unvaccinated COVID-19 Patients.

Aim: Our cohort study aimed to investigate the dynamic changes of lymphocyte subsets and their abilities to predict disease severity and prognosis in primary infection and unvaccinated COVID-19 patients. Methods: A total of 773 cases, including 718 primary infection and unvaccinated COVID-19 patients and 55 controls. COVID-19 patients were assigned to severe and nonsevere groups according to disease severity, as well as survival and death groups according to prognosis. Serum samples were collected to measure the numbers of total lymphocytes and lymphocyte subsets. The differences among different severity groups were analyzed. Spearman correlation was performed to assess associations between lymphocyte subsets and disease severity and prognosis. Meanwhile, receiver operating characteristic (ROC) curves were also analyzed to find optimal cutoff points. Results: At admission, the severe group demonstrated significantly lower total lymphocyte counts and percentages, CD3 Conclusion: In primary infection and unvaccinated COVID-19 patients total lymphocytes and T cell, B cell and NK cell subsets at COVID-19 onset play valuable roles in predicting disease severity and prognosis. Clinical Trial Registry: Chinese Clinical Trial Register ChiCTR2000034563.