Analysis of the Long-Term Impact on Cellular Immunity in COVID-19-Recovered Individuals Reveals a Profound NKT Cell Impairment.

mBio 2021 Apr 27

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The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected over 120 million people and killed over 2.7 million individuals by March 2021. While acute and intermediate interactions between SARS-CoV-2 and the immune system have been studied extensively, long-term impacts on the cellular immune system remain to be analyzed. Here, we comprehensively characterized immunological changes in peripheral blood mononuclear cells in 49 COVID-19-convalescent individuals (CI) in comparison to 27 matched SARS-CoV-2-unexposed individuals (UI). Despite recovery from the disease for more than 2 months, CI showed significant decreases in frequencies of invariant NKT and NKT-like cells compared to UI. Concomitant with the decrease in NKT-like cells, an increase in the percentage of annexin V and 7-aminoactinomycin D (7-AAD) double-positive NKT-like cells was detected, suggesting that the reduction in NKT-like cells results from cell death months after recovery. Significant increases in regulatory T cell frequencies and TIM-3 expression on CD4 and CD8 T cells were also observed in CI, while the cytotoxic potential of T cells and NKT-like cells, defined by granzyme B (GzmB) expression, was significantly diminished. However, both CD4 and CD8 T cells of CI showed increased Ki67 expression and were fully able to proliferate and produce effector cytokines upon T cell receptor (TCR) stimulation. Collectively, we provide a comprehensive characterization of immune signatures in patients recovering from SARS-CoV-2 infection, suggesting that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease.IMPORTANCE Wuhan was the very first city hit by SARS-CoV-2. Accordingly, the patients who experienced the longest phase of convalescence following COVID-19 reside here. This enabled us to investigate the "immunological scar" left by SARS-CoV-2 on cellular immunity after recovery from the disease. In this study, we characterized the long-term impact of SARS-CoV-2 infection on the immune system and provide a comprehensive picture of cellular immunity of a convalescent COVID-19 patient cohort with the longest recovery time. We revealed that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease; in particular, a profound NKT cell impairment was found in the convalescent phase of COVID-19. Copyright © 2021 Liu et al.

Citation

Jia Liu, Xuecheng Yang, Hua Wang, Ziwei Li, Hui Deng, Jing Liu, Shue Xiong, Junyi He, Xuemei Feng, Chunxia Guo, Weixian Wang, Gennadiy Zelinskyy, Mirko Trilling, Kathrin Sutter, Tina Senff, Christopher Menne, Joerg Timm, Yanfang Zhang, Fei Deng, Yinping Lu, Jun Wu, Mengji Lu, Dongliang Yang, Ulf Dittmer, Baoju Wang, Xin Zheng. Analysis of the Long-Term Impact on Cellular Immunity in COVID-19-Recovered Individuals Reveals a Profound NKT Cell Impairment. mBio. 2021 Apr 27;12(2)