IL6 and obesity due to melanocortin 4 receptor deficiency: Increased levels of C-reactive protein (CRP), a serum acute-phase reactant produced by the liver, and other proinflammatory cytokines secreted by the adipose tissue such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), have been reported in patients with obesity [5,6,7,8].