As these findings strongly indicate that CD8+ T cells stimulate the infiltrated number of ATMs and that the alterations in the number of AT CD8 T+ cells were anterior to the increase in the ATM numbers in obesity, we speculated that the recruitment of ATMs was induced by AT CD8+ T cells under conditions of obesity, thus inducing insulin resistance development. Here, CD8A is linked to obesity due to melanocortin 4 receptor deficiency.