Impaired Cellular Immunity to SARS-CoV-2 in Severe COVID-19 Patients

• Main Authors: Ling Ni, Meng-Li Cheng, Yu Feng, Hui Zhao, Jingyuan Liu, Fang Ye, Qing Ye, Gengzhen Zhu, Xiaoli Li, Pengzhi Wang, Jing Shao, Yong-Qiang Deng, Peng Wei, Fang Chen, Cheng-Feng Qin, Guoqing Wang, Fan Li, Hui Zeng, Chen Dong
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2021-02-01
• Series: Frontiers in Immunology
• Subjects: interferon gamma; T cells; neutralization antibody; adaptive immunity; acute respiratory distress syndrome; SARS-CoV-2
• Online Access: https://www.frontiersin.org/articles/10.3389/fimmu.2021.603563/full

The high infection rate and rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) make it a world-wide pandemic. Individuals infected by the virus exhibited different degrees of symptoms, and most convalescent individuals have been shown to develop both cellular and humoral immune responses. However, virus-specific adaptive immune responses in severe patients during acute phase have not been thoroughly studied. Here, we found that in a group of COVID-19 patients with acute respiratory distress syndrome (ARDS) during hospitalization, most of them mounted SARS-CoV-2-specific antibody responses, including neutralizing antibodies. However, compared to healthy controls, the percentages and absolute numbers of both NK cells and CD8+ T cells were significantly reduced, with decreased IFNγ expression in CD4+ T cells in peripheral blood from severe patients. Most notably, their peripheral blood lymphocytes failed in producing IFNγ against viral proteins. Thus, severe COVID-19 patients at acute infection stage developed SARS-CoV-2-specific antibody responses but were impaired in cellular immunity, which emphasizes on the role of cellular immunity in COVID-19.