T-Cell Subset Counts in Peripheral Blood Can Be Used as Discriminatory Biomarkers for Diagnosis and Severity Prediction of Coronavirus Disease 2019

J Infect Dis. 2020 Jun 29;222(2):198-202. doi: 10.1093/infdis/jiaa252.


This study evaluated the significance of lymphocyte subset detection in peripheral blood in the diagnosis and prognosis of coronavirus disease 2019 (COVID-19). Our results revealed that CD3+ T cells, CD4+ T cells, CD8+ T cells, and natural killer cells were significantly decreased in patients with COVID-19. These patients had a relatively slight decrease in CD4+ T cells but a severe decrease in CD8+ T cells. The significantly elevated CD4/CD8 ratio was observed in COVID-19 patients. T-cell subset counts were related to the severity and prognosis of COVID-19, suggesting that the counts of CD8+ T and CD4+ T cells can be used as diagnostic markers of COVID-19 and predictors of disease severity.

Keywords: SARS-CoV2; diagnosis; lymphocyte subsets; prognosis.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Betacoronavirus*
  • Biomarkers / blood
  • CD4 Lymphocyte Count
  • CD4-CD8 Ratio
  • CD8-Positive T-Lymphocytes
  • COVID-19
  • COVID-19 Testing
  • Clinical Laboratory Techniques*
  • Coronavirus Infections / diagnosis*
  • Coronavirus Infections / immunology*
  • Female
  • Humans
  • Killer Cells, Natural
  • Lymphocyte Count*
  • Male
  • Middle Aged
  • Pandemics
  • Patient Acuity
  • Pneumonia, Viral / diagnosis*
  • Pneumonia, Viral / immunology*
  • SARS-CoV-2
  • Sensitivity and Specificity
  • T-Lymphocyte Subsets*
  • Young Adult


  • Biomarkers