In the case of obesity, excessive inflammation is caused by adipocyte production of inflammatory adipokines (fat tissue-associated cytokines) such as interleukin (IL)-8, plasminogen activator inhibitor (PAI)-1, monocyte chemoattractant protein (MCP)-1, IL-6, tumor necrosis factor-alpha (TNF-α), and IL-18. Here, TNF is linked to obesity due to melanocortin 4 receptor deficiency.