Characteristics of Peripheral Lymphocyte Subset Alteration in 2019-nCoV Pneumonia

Background: Since December 2019, novel coronavirus (2019-nCoV)-infected pneumonia (NCP) occurred in Wuhan, and rapidly spread throughout China. We aimed to clarify the characteristics and clinical significance of peripheral lymphocyte subset alteration in NCP. Methods: The levels of peripheral lymphocyte subsets were measured by flow cytometry in 60 NCP patients before and after treatment, and their association with clinical characteristics and efficacy was analyzed. Findings: Compared to healthy controls, NCP patients had a significant decrease of total lymphocytes, CD4+ T cells, CD8+ T cells, B cells and natural killer (NK) cells. In NCP patients, severe cases had a lower level of CD4+ T cells and CD8+ T cells than mild cases. CD8+ T cell levels were negatively correlated with inflammatory indicators of erythrocyte sedimentation rat (ESR), C-reactive protein (CRP) and interleukin-6 (IL-6), while CD4+/CD8+ ratio was positively correlated. Levels of total lymphocytes and CD4+ T cells were negatively correlated with ESR, and NK cells in negative correlation with IL-6. After one-week treatment, 37 patients (67%) reached clinical response, and had a significant increase of total lymphocytes, CD8+ T cells and B cells. In multivariate analysis, post-treatment decrease of CD8+ T cells and B cells and increase of CD4+/CD8+ ratio were indicated as independent predictors for poor clinical efficacy. Interpretation: Peripheral lymphocyte subset alteration demonstrated a significant association with the clinical characteristics and efficacy of NCP. CD8+ T cells tended to be an independent predictor for NCP severity and treatment efficacy. Funding Statement: This study was supported by the Program of Excellent Doctoral (Postdoctoral) of Zhongnan Hospital of Wuhan University (Grant No. ZNYB2019003). Declaration of Interests: The authors declared no competing interests. Ethics Approval Statement: This study was approved by the ethics committee of Zhongnan Hospital of Wuhan University (No. 2020011). Written informed consent was obtained from patients.