IL6 and obesity due to melanocortin 4 receptor deficiency: In obesity, inflammation can occur due to increased levels of chemokines (such as CCL2 and CXCL1) and inflammatory cytokines (such as tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6)) secreted from accumulated fat in hepatocytes and adipocytes, causing insulin resistance (Kim et al., 2017; Xu et al., 2003).