Obesity is characterized by increased levels of circulating proinflammatory cytokines [including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6], accumulation of leukocytes within the adipose tissue and other organs, activation of macrophages in the liver and fat, and activation of proinflammatory signaling pathways in multiple organs (43, 44). This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.