AUTHOR=Ni Ling , Cheng Meng-Li , Feng Yu , Zhao Hui , Liu Jingyuan , Ye Fang , Ye Qing , Zhu Gengzhen , Li Xiaoli , Wang Pengzhi , Shao Jing , Deng Yong-Qiang , Wei Peng , Chen Fang , Qin Cheng-Feng , Wang Guoqing , Li Fan , Zeng Hui , Dong Chen TITLE=Impaired Cellular Immunity to SARS-CoV-2 in Severe COVID-19 Patients JOURNAL=Frontiers in Immunology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.603563 DOI=10.3389/fimmu.2021.603563 ISSN=1664-3224 ABSTRACT=

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.