CD4 and obesity due to melanocortin 4 receptor deficiency: Adipose tissue contains most types of immune cells, which under conditions of obesity contribute to a complex network of inflammation and IR with activation and infiltration of pro-inflammatory immune cells in adipose tissue, including macrophages, neutrophils, eosinophils, mast cells, NK cells, MAIT cells, CD4 T cells, CD8 T cells, regulatory T cells and B cells, as well as high levels of pro-inflammatory molecules (161).