Peripheral CD4+ T cell subsets and antibody response in COVID-19 convalescent individuals
Fang Gong, Yaping Dai, Ting Zheng, Liang Cheng, Dan Zhao, Hao Wang, Min Liu, Pei Hao, Tengchuan Jin, Di Yu, Pengcheng Zhou
Abstract
BACKGROUNDMarked progress is achieved in understanding the physiopathology of coronavirus disease 2019 (COVID-19), which caused a global pandemic. However, the CD4+ T cell population critical for antibody response in COVID-19 is poorly understood.METHODSIn this study, we provided a comprehensive analysis of peripheral CD4+ T cells from 13 COVID-19 convalescent patients, defined as confirmed free of SARS-CoV-2 for 2 to 4 weeks, using flow cytometry and magnetic chemiluminescence enzyme antibody immunoassay. The data were correlated with clinical characteristics.RESULTSWe observed that, relative to healthy individuals, convalescent patients displayed an altered peripheral CD4+ T cell spectrum. Specifically, consistent with other viral infections, cTfh1 cells associated with SARS-CoV-2-targeting antibodies were found in COVID-19 covalescent patients. Individuals with severe disease showed higher frequencies of Tem and Tfh-em cells but lower frequencies of Tcm, Tfh-cm, Tfr, and Tnaive cells, compared with healthy individuals and patients with mild and moderate disease. Interestingly, a higher frequency of cTfh-em cells correlated with a lower blood oxygen level, recorded at the time of admission, in convalescent patients. These observations might constitute residual effects by which COVID-19 can impact the homeostasis of CD4+ T cells in the long-term and explain the highest ratio of class-switched virus-specific antibody producing individuals found in our severe COVID-19 cohort.CONCLUSIONOur study demonstrated a close connection between CD4+ T cells and antibody production in COVID-19 convalescent patients.FUNDINGSix Talent Peaks Project in Jiangsu Province and the National Natural Science Foundation of China (NSFC).