Abstract: Objective To investigate the changes of blood routine examination and lymphocyte subsets in patients with coronavirus disease 2019 (COVID-19). Methods Sixty-six confirmed COVID-19 patients admitted to Fuyang Second People's Hospital from January to February 2020 were included in this study.Fifty-six patients suspected but ultimately not diagnosed as novel coronavirus (SARS-CoV-2) infection were used as the control group. Changes of blood routine examination and lymphocyte subsets were compared between the two groups. Logistic regression analysis was used for analysing blood cytological factors of COVID-19 patients. Results Compared with the control group, white blood cell (WBC), neutrophils (NEU), lymphocytes (LYM), CD4+ T cells, CD8+ T cells, and B lymphocytes were all reduced in COVID- 19 group (P＜0.05). Logistic regression analysis showed that the higher levels of CD4+ T-lymphocytes were protective factor for SARS-CoV-2 infection (OR=0.997,95%CI:0.994-0.999). Spearman analysis showed that CD4+ T cells and LYM count were positively correlated (rs =0.829, P＜0.01). Conclusion COVID-19 can cause the decrease of peripheral blood T lymphocyte count in patients. T lymphocyte subsets provide relatively reliable reference for clinical diagnosis and treatment of SARS-CoV-2 infection.

Key words: pneumonia, viral, coronavirus disease 2019, SARS-CoV-2, lymphocytes, CD4-positive T-lymphocytes; blood routine items