To investigate whether increased weight gain affected the expression of Helios+ and Helios− Foxp3+ Tregs in the lungs similarly and how concomitant allergic inflammation modified this, we analyzed cell subpopulations in the lungs of allergic and naïve mice at different grades of obesity as compared to their counterparts in adipose tissue. Here, FOXP3 is linked to obesity due to melanocortin 4 receptor deficiency.