Obesity-associated adipose inflammation, for instance, is characterized by increased infiltration of macrophages (Weisberg et al., 2003; Xu et al., 2003) and other immune cells (Liu et al., 2009; Nishimura et al., 2009; Winer et al., 2009; Ohmura et al., 2010), and macrophage infiltration has been shown to be stimulated by obese adipose tissue expression of Ccl2/MCP-1 (Kamei et al., 2006; Weisberg et al., 2006). This evidence concerns the gene CCL2 and obesity due to melanocortin 4 receptor deficiency.