Background De-regulated host response to severe coronavirus disease 2019 (COVID-19), directly referring to the concept of sepsis-associated immunological dysregulation, seems to be a strong signature of severe COVID-19. Myeloid cells phenotyping is well recognized to diagnose critical illness-induced immunodepression in sepsis and has not been well characterized in COVID-19. The aim of this study is to review phenotypic characteristics of myeloid cells and evaluate their relations with the occurrence of secondary infection and mortality in patients with COVID-19 admitted in an intensive care unit. Methods Retrospective analysis of the circulating myeloid cells phenotypes of adult COVID-19 critically ill patients. Phenotyping circulating immune cells was performed by flow cytometry daily for routine analysis and twice weekly for lymphocytes and monocytes subpopulations analysis, as well as monocyte human leukocyte antigen (mHLA)-DR expression. Results Out of the 29 critically ill adult patients with severe COVID-19 analyzed, 12 (41.4%) developed secondary infection and six patients died during their stay. Monocyte HLA-DR kinetics was significantly different between patients developing secondary infection and those without, respectively, at day 5–7 and 8–10 following admission. The monocytes myeloid-derived suppressor cells to total monocytes ratio was associated with 28- and 60-day mortality. Those myeloid characteristics suggest three phenotypes: hyperactivated monocyte/macrophage is significantly associated with mortality, whereas persistent immunodepression is associated with secondary infection occurrence compared to transient immunodepression. Conclusions Myeloid phenotypes of critically ill COVID-19 patients may be associated with development of secondary infection, 28- and 60-day mortality. Supplementary Information The online version contains supplementary material available at 10.1186/s13613-021-00896-4.
【저자키워드】 COVID-19, Secondary infection, myeloid-derived suppressor cells, Sepsis-induced immunodepression, mHLA-DR, 【초록키워드】 Mortality, intensive care, severe COVID-19, Infection, Sepsis, host response, flow cytometry, Antigen, monocyte, lymphocyte, Critically ill, Characteristics, Patient, phenotype, expression, Admission, Critical, HLA-DR, myeloid, critically ill patients, diagnose, Phenotyping, Analysis, Immune cell, COVID-19 patient, dysregulation, leukocyte, supplementary material, severe coronavirus disease, circulating, phenotypic, subpopulation, myeloid cell, immunological, Cell, Occurrence, Result, analyzed, evaluate, significantly, was performed, characterized, patients died, patients with COVID-19, 【제목키워드】 severe COVID-19, Infection, phenotype, predict, myeloid, pilot study,