pneumonia (eg, in the presence of individual cytokine or receptor polymorphisms), IL-33 might abnormally upregulate expression of its own receptor ST2 (also known as IL-1RL1) on Treg cells, resulting in increased expression of the canonical Th2 transcription factor GATA-binding factor 3 (GATA3), which impairs the suppressive function of Treg cells. The dysregulation of GATA3+ Foxp3+ Treg cells might result in impaired immunological tolerance and increased secretion of type 2 cytokines, thus promoting autoinflammatory lung disease.16 TGFβ2, which is also increased in the bronchoalveolar lavage fluid of patients with COVID-19,11 might