C5AR2 and obesity due to melanocortin 4 receptor deficiency: Circulating ASP levels increase in people with obesity, insulin resistance or Type 2 Diabetes Mellitus (T2DM), and metabolic syndrome, which increases monocyte chemoattractant protein-1 (MCP-1) and keratinocyte-derived chemokine (KC or IL-8) from their adipocytes through C5L2 or C5aR2 interaction without impacting IL-6 and adiponectin production (243, 244).