IFNG and obesity due to melanocortin 4 receptor deficiency: In obesity, under a high-fat diet (HFD), pro-inflammatory TH1 and M1 macrophages were reported to be activated and to produce IFN-γ, TNF-α, and IL-12 [11, 13], whereas the differentiation of naïve T-cells into anti-inflammatory TH2 which secrete IL-4, IL-10 and IL-13, as well as the activity of Treg cells, were reduced [14].