CCL2 and obesity due to melanocortin 4 receptor deficiency: In obesity, the main players in the systemic chronic inflammation are the increased numbers of pro-inflammatory macrophages and production of deregulated hormones and cytokines, such as monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α), by the adipose tissue [2].