Although it is clear that infiltrating macrophages are increased in WAT in models of genetic or high-fat-diet induced obesity and they play an active role in this pathology, mice that are leptin or LepR deficient (ob/ob and db/db respectively) present lower levels of these macrophages and low inflammatory gene expression, even with higher body weight and adiposity [198,199]. This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.