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Intermediate Monocytes with PD-L1 and CD62L Expression as a Possible Player in Active SARS-CoV-2 Infection
Elżbieta Rutkowska1, Iwona Kwiecień1, Krzysztof Kłos2
1Laboratory of Flow Cytometry, Department of Internal Medicine and Hematology, Military Institute of Medicine, 04-141 Warsaw, Poland.
Insights
Monocyte subpopulations in COVID-19 patients show distinct PD-L1 and CD62L expression compared to convalescent individuals. Monitoring these monocyte subsets may aid in predicting recovery from SARS-CoV-2 infection.
Area of Science:
- Immunology
- Virology
- Hematology
Background:
- Monocytes are crucial in viral infections, but their specific roles and subsets in COVID-19 remain unclear.
- Understanding monocyte dynamics during SARS-CoV-2 infection is vital for disease management.
Purpose of the Study:
- To analyze classical, intermediate, and non-classical monocyte subsets expressing PD-L1, CD62L, TIM-3, and CD86 in COVID-19 patients versus convalescent individuals.
- To identify potential biomarkers for distinguishing SARS-CoV-2 infection and predicting recovery.
Main Methods:
- Flow cytometry analysis of peripheral blood monocytes from 55 COVID-19 patients and 51 convalescent patients.
- Quantification of monocyte proportions and expression levels of PD-L1, CD62L, TIM-3, and CD86.
Main Results:
- COVID-19 patients exhibited lower overall monocyte counts and proportions, particularly non-classical monocytes.
- Increased proportions and PD-L1 expression on intermediate monocytes were observed in COVID-19 patients.
- Elevated CD62L expression on monocytes was found in COVID-19 patients compared to convalescents.
Conclusions:
- PD-L1 and CD62L expression on monocyte subsets can differentiate COVID-19 patients from those recovered.
- These monocyte subset profiles may indicate a predisposition for rapid recovery from SARS-CoV-2 infection.
- Monitoring peripheral blood monocyte subsets could serve as a valuable diagnostic and prognostic tool for COVID-19.
Abstract:
Monocytes play a role in viral biology, but little is known about the monocyte subpopulation in the course of COVID-19 disease. The aim of the study was the analysis of classical, intermediate and non-classical monocytes with expression of PD-L1 and CD62L, TIM-3 and CD86 molecules in peripheral blood (PB) to distinguish patients with SARS-CoV-2 infection from convalescent patients. The study group consisted of 55 patients with SARS-CoV-2 infection and 51 convalescent patients. The cells were analyzed by flow cytometry. The number and proportion of monocytes were lower in patients with COVID-19 than convalescent patients. We observed a lower proportion of non-classical monocytes in COVID-19 patients than convalescent ones. There was a higher proportion of PDL-1-positive intermediate monocytes in COVID-19 patients than convalescent ones. We noticed a higher geometric mean fluorescence intensity (GeoMean) of PD-L1 on intermediate monocytes in COVID-19 patients than convalescent patients, and a higher proportion of CD62L-positive monocytes in COVID-19 patients in comparison with convalescent ones. We found a higher GeoMean of CD62L on monocytes in COVID-19 patients than convalescent ones. Assessment of PD-L1- and CD62L-positive monocyte subsets may identify patients with a possible predisposition for rapid recovery. The monitoring of monocyte subsets in PB might be a useful test in COVID-19 patients.
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