Toward an understanding of regulatory T cells in COVID-19: A systematic review

J Med Virol. 2021 Jul;93(7):4167-4181. doi: 10.1002/jmv.26891. Epub 2021 Apr 1.


A more detailed understanding of Treg cells in COVID-19 infection will broaden our knowledge of the COVID-19 immunopathology and give us more insight into the curative immune-based strategies. We systematically searched electronic databases (PubMed, Google Scholar, EMBASE) and identified 18 eligible studies. Despite the inconsistencies between the results, we observed a trend toward decreasing Treg levels in severe COVID-19 patients. This finding underlines the hypothesis that Tregs play a role in the pathogenesis of COVID-19. Further studies on Tregs' functional aspects are necessary to illustrate Tregs' potential role in COVID-19 disease.

Keywords: COVID-19; immune response; regulatory T cell.

Publication types

  • Systematic Review

MeSH terms

  • CD4 Lymphocyte Count
  • COVID-19 / immunology*
  • Cytokines / blood
  • Humans
  • SARS-CoV-2 / immunology*
  • T-Lymphocytes, Regulatory / immunology*


  • Cytokines