Restoration of leukomonocyte counts is associated with viral clearance in COVID-19 hospitalized patients

Chen, Xiaoping; Ling, Jiaxin; Mo, Pingzheng; Zhang, Yongxi; Jiang, Qunqun; Ma, Zhiyong; Cao, Qian; Hu, Wenjia; Zou, Shi; Chen, Liangjun; Yao, Lei; Luo, Mingqi; Chen, Tielong; Deng, Liping; Liang, Ke; Song, Shihui; Yang, Rongrong; Zheng, Ruiying; Gao, Shicheng; Gui, Xien; Ke, Hengning; Hou, Wei; Lundkvist, Ã…ke; Xiong, Yong

Background: Viral clearance is one important indicator for the recovery of SARS-CoV-2 infected patients. Suboptimal T and B cell responses can delay viral clearance in MERS and SARS patients. The role of leukomonocytes in viral clearance of COVID-19 patients is not yet well defined.Methods: From January 26 to February 28, 2020, an observational study was launched at Zhongnan Hospital of Wuhan University, Wuhan, China. We enrolled 25 laboratory-confirmed COVID-19 patients, whose throat-swab specimens were tested positive for SARS-CoV-2 infection by qRT-PCR. We comprehensively analyzed clinical records, counts of lymphocyte subsets including CD3+, CD4+, CD8+ T cells, B cells and NK cells in the patients who successfully cleared SARS-CoV-2, and compared to those that failed to, after a standardized treatment of 8-14 days. Findings: In 25 enrolled COVID-19 patients, lymphopeniawas a common feature. After the treatment, 14 patients were tested negative for SARS-CoV-2. The patients that cleared the infection had restored the numbers of CD3+, CD4+, CD8+ T cellsand B cells as compared to the still viral RNA positive patients, while the recovered patients had a higher count of leukomonocytes. Conclusions: By comparison of leukomonocytes counts in COVID-19 patients at different stages of the disease, we found that CD3+, CD4+, CD8+ T cells and B cells appear to play important roles in viral clearance. The restoration of leukomonocytes counts from peripheral blood can be used as prognosis for the recovery of an COVID-19 infection. We propose that restoration of leukomonocytes counts can be added to the COVID-19 diagnostic guidanceas a criterion for releasing and discharging patients.