FOXP3 and influenza: Interestingly, during acute influenza infection, lung Treg cells, including the TR-Treg and Circ-Treg cell subsets displayed decreased Foxp3 expression while Foxp3 expression remained stable in Treg cells extracted from the lymph nodes and spleens (Figure 2A, B), which is however consistent with previous findings that Foxp3 expression is downregulated during inflammation (34, 35).