IL6 and obesity due to melanocortin 4 receptor deficiency: Although all these data indicate that the adipocytes appear to be the major source of elevated IL-6, IL-8, and MCP-1 levels observed in obesity (Shimomura et al., 1996; Morange et al., 1999), it is still a matter of debate whether this is a result of stimulation of adipocytes via direct cell contacts with macrophages or an effect caused by hormones and cytokines released from the macrophages (Loskutoff and Samad, 1998).