Assessment of CD39 expression in regulatory T‐cell subsets by disease severity in adult and juvenile COVID‐19 cases

COVID‐19 is a disease characterized by acute respiratory failure and is a major health problem worldwide. Here, we aimed to investigate the role of CD39 expression in Treg cell subsets in COVID‐19 immunopathogenesis and its relationship to disease severity. One hundred and ninety COVID‐19 patients (juveniles, adults) and 43 volunteers as healthy controls were enrolled in our study. Flow cytometric analysis was performed using a 10‐color monoclonal antibody panel from peripheral blood samples. In adult patients, CD39+ Tregs increased with disease severity. In contrast, CD39+ Tregs were decreased in juvenile patients in an age‐dependent manner. Overall, our study reveals an interesting profile of CD39‐expressing Tregs in adult and juvenile cases of COVID‐19. Our results provide a better understanding of the possible role of Tregs in the mechanism of immune response in COVID‐19 cases. Research Highlights CD39+ Tregs increased with disease severity in adult COVID‐19 cases. In addition, significant changes were also observed in other Treg subsets. Treg subsets in the juvenile COVID‐19 cases showed age‐related variability but were significantly lower than in the healthy control group. Consistent correlations were found between laboratory findings in adult COVID‐19 cases and Treg subsets.