CD4 and allergic asthma: Moreover, Mays et al. showed that overexpression of Foxp3 in mouse lung with a modified mRNA could prevent allergic asthma in vivo. They also showed that this modified mRNA induced Foxp3 upregulation in CD4+ cells.30 Although we used a different method of Foxp3 gene delivery (that is, adenovirus), our results are consistent with those of this previous study.