The Impact of Peripheral Eosinophil Counts and Eosinophil to Lymphocyte Ratio (ELR) in the Clinical Course of COVID-19 Patients: A Retrospective Study

In Vivo. 2021 Jan-Feb;35(1):641-648. doi: 10.21873/invivo.12303.

Abstract

Background/aim: Eosinophils are blood cells responsible for response against parasites and allergens. Eosinophil to lymphocyte ratio (ELR) is a biomarker for inflammatory conditions. Our aim was to evaluate the role of eosinophils and ELR in COVID-19 patients.

Patients and methods: The study included 96 patients hospitalized with COVID-19. They were classified into moderate to severe cases and critical cases. Eosinophils and ELR were determined in both groups, in patients that died or survived and were correlated to duration of hospitalization.

Results: There was a statistically significant decrease in eosinophils and ELR between patients that died and patients that survived (p<0.05), and in mean values of the two biomarkers (p<0.05 for eosinophils and p<0.05 for ELR) between patients hospitalized for more or less than 15 days among those with moderate to severe disease.

Conclusion: Lower eosinophil counts and ERL could probably predict worse outcome in COVID-19 patients.

Keywords: COVID-19; Eosinophils; biomarker; lymphocyte; prediction; ratio.

MeSH terms

  • Adult
  • Aged
  • Biomarkers / blood
  • COVID-19 / blood
  • COVID-19 / diagnosis*
  • COVID-19 / virology
  • Eosinophils*
  • Female
  • Humans
  • Length of Stay / statistics & numerical data
  • Leukocyte Count
  • Lymphocytes*
  • Male
  • Middle Aged
  • Prognosis
  • Retrospective Studies
  • SARS-CoV-2 / isolation & purification*
  • SARS-CoV-2 / physiology
  • Sensitivity and Specificity
  • Severity of Illness Index

Substances

  • Biomarkers