Colonization of the adipose tissue by proinflammatory M1 macrophages is a striking feature of progressive obesity and involves the increased expression of tumor necrosis factor (TNF)-α, IL-1β, IL-6, IFN-γ, IL-8, IP-10, CCL2, CCL3, CCL4, CCL5, Eotaxins (CCL-11, 24, 26), CX3CL1 and several other chemokines. The gene discussed is CCL4; the disease is obesity due to melanocortin 4 receptor deficiency.