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Myeloid cell dynamics correlating with clinical outcomes of severe COVID-19 in Japan
Tomohiro Takano1, Takayuki Matsumura1, Yu Adachi1
1Department of Immunology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
Insights
In Japanese COVID-19 patients, polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) transiently expanded in severe cases, correlating with survival. This PMN-MDSC expansion may predict better prognosis in severe COVID-19.
Area of Science:
- Immunology
- Hematology
- Infectious Diseases
Background:
- Severe COVID-19 is associated with myeloid cell expansion, but data from low-mortality regions like Japan are limited.
- Previous studies focused on European cohorts, leaving characteristics of myeloid cell subsets in different populations largely unknown.
Purpose of the Study:
- To investigate the dynamics of myeloid-derived suppressor cell (MDSC) subsets in Japanese COVID-19 patients.
- To determine if specific MDSC subsets correlate with disease severity and patient prognosis.
Main Methods:
- Analysis of blood samples from Japanese COVID-19 patients.
- Examination of cellular dynamics of MDSC subsets.
- Correlation analysis with plasma cytokine/chemokine levels, including IL-8.
Main Results:
- Polymorphonuclear MDSCs (PMN-MDSCs) showed transient expansion in severe COVID-19 cases, unlike mild or moderate cases.
- This PMN-MDSC expansion was observed in survivors and subsided before discharge, but not in non-survivors.
- PMN-MDSC frequencies positively correlated with IL-8 levels, suggesting IL-8's role in PMN-MDSC recruitment.
Conclusions:
- Transient expansion of PMN-MDSCs is associated with improved clinical outcomes in Japanese COVID-19 patients.
- The PMN-MDSC subset may serve as a prognostic predictor for severe COVID-19 in this population.
- Findings contrast with European cohorts, highlighting regional differences in COVID-19 immunopathology.
Abstract:
An expanded myeloid cell compartment is a hallmark of severe coronavirus disease 2019 (COVID-19). However, data regarding myeloid cell expansion have been collected in Europe, where the mortality rate by COVID-19 is greater than those in other regions including Japan. Thus, characteristics of COVID-19-induced myeloid cell subsets remain largely unknown in the regions with low mortality rates. Here, we analyzed cellular dynamics of myeloid-derived suppressor cell (MDSC) subsets and examined whether any of them correlate with disease severity and prognosis, using blood samples from Japanese COVID-19 patients. We observed that polymorphonuclear (PMN)-MDSCs, but not other MDSC subsets, transiently expanded in severe cases but not in mild or moderate cases. Contrary to previous studies in Europe, this subset selectively expanded in survivors of severe cases and subsided before discharge, but such transient expansion was not observed in non-survivors in Japanese cohort. Analysis of plasma cytokine/chemokine levels revealed positive correlation of PMN-MDSC frequencies with IL-8 levels, indicating the involvement of IL-8 on recruitment of PMN-MDSCs to peripheral blood following the onset of severe COVID-19. Our data indicate that transient expansion of the PMN-MDSC subset results in improved clinical outcome. Thus, this myeloid cell subset may be a predictor of prognosis in cases of severe COVID-19 in Japan.
