T Cells: Warriors of SARS-CoV-2 Infection

Trends Immunol. 2021 Jan;42(1):18-30. doi: 10.1016/j.it.2020.11.002. Epub 2020 Nov 13.


Severe infection with severe acute respiratory syndrome coronavirus (SARS-CoV)-2 is characterized by massive cytokine release and T cell loss. The exaggerated host immune response, incapable of viral clearance, instead aggravates respiratory distress, as well as cardiac, and/or damage to other organs. The mortality pattern of SARS-CoV-2 infection, higher in older versus younger adults and almost absent in children, is possibly caused by the effects of age and pre-existing comorbidities on innate and adaptive immunity. Here, we speculate that the abnormal and excessive immune response to SARS-CoV-2 infection partly depends on T cell immunological memory, which is more pronounced in adults compared with children, and may significantly contribute to immunopathology and massive collateral damage in coronavirus disease 2019 (COVID-19) patients.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptive Immunity / immunology*
  • COVID-19 / immunology*
  • COVID-19 / prevention & control
  • COVID-19 / virology
  • Cytokines / immunology
  • Cytokines / metabolism
  • Humans
  • Immunity, Innate / immunology*
  • Immunologic Memory / immunology
  • Models, Immunological
  • SARS-CoV-2 / immunology*
  • SARS-CoV-2 / physiology
  • T-Lymphocyte Subsets / cytology
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism


  • Cytokines