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Updated: Oct 8, 2025
Single-cell Analysis of Immunophenotype and Cytokine Production in Peripheral Whole Blood via Mass Cytometry
Published on: June 26, 2018
High CD169 Monocyte/Lymphocyte Ratio Reflects Immunophenotype Disruption and Oxygen Need in COVID-19 Patients
Antonella Minutolo1, Vita Petrone1, Marialaura Fanelli1
1Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy.
Insights
Sialoadhesin (CD169) is elevated in COVID-19 patients, correlating with immune dysfunction and predicting respiratory outcomes. SARS-CoV-2 spike protein specifically induces CD169, highlighting its role as an early disease biomarker.
Area of Science:
- Immunology
- Virology
- Biomarker Discovery
Background:
- Sialoadhesin (CD169) is overexpressed in COVID-19 patients' blood, serving as an early disease biomarker.
- This study investigates CD169's role in predicting COVID-19 progression and clinical outcomes.
Purpose of the Study:
- To analyze CD169 expression in COVID-19 blood cells.
- To assess CD169 as a predictive marker for disease progression and clinical outcomes.
Main Methods:
- Flow cytometry analyzed the CD169 median fluorescence intensity ratio between monocytes and lymphocytes (CD169 RMFI) in COVID-19 patients (COV) and healthy donors (HDs).
- Correlations were assessed with immunophenotyping, inflammatory markers, cytokine mRNA, pulmonary involvement, and disease progression.
- In vitro studies examined SARS-CoV-2 spike protein's effect on CD169 RMFI and cytokine gene transcription in peripheral blood mononuclear cells (PBMCs).
Main Results:
- CD169 RMFI was significantly higher in COV compared to HDs.
- Elevated CD169 RMFI correlated with CD8 T-cell senescence/exhaustion markers, B-cell maturation/differentiation, inflammatory markers, and pneumonia severity in untreated patients.
- CD169 RMFI was associated with respiratory outcomes during hospitalization.
- SARS-CoV-2 spike protein dose-dependently induced CD169 RMFI and IL-6/IL-10 gene transcription in vitro.
Conclusions:
- CD169 is induced by the SARS-CoV-2 spike protein.
- CD169 serves as an early biomarker for assessing immune dysfunction and predicting respiratory outcomes in COVID-19 patients.
Background:
Sialoadhesin (CD169) has been found to be overexpressed in the blood of COVID-19 patients and identified as a biomarker in early disease. We analyzed CD169 in the blood cells of COVID-19 patients to assess its role as a predictive marker of disease progression and clinical outcomes.
Methods:
The ratio of the median fluorescence intensity of CD169 between monocytes and lymphocytes (CD169 RMFI) was analyzed by flow cytometry in blood samples of COVID-19 patients (COV) and healthy donors (HDs) and correlated with immunophenotyping, inflammatory markers, cytokine mRNA expression, pulmonary involvement, and disease progression.
Results:
CD169 RMFI was high in COV but not in HDs, and it correlated with CD8 T-cell senescence and exhaustion markers, as well as with B-cell maturation and differentiation in COV. CD169 RMFI correlated with blood cytokine mRNA levels, inflammatory markers, and pneumonia severity in patients who were untreated at sampling, and was associated with the respiratory outcome throughout hospitalization. Finally, we also report the first evidence of the specific ability of the spike protein of SARS-CoV-2 to trigger CD169 RMFI in a dose-dependent manner in parallel with IL-6 and IL-10 gene transcription in HD PBMCs stimulated in vitro.
Conclusion:
CD169 is induced by the spike protein and should be considered as an early biomarker for evaluating immune dysfunction and respiratory outcomes in COVID-19 patients.
