TNF and obesity due to melanocortin 4 receptor deficiency: Conversely, under pathological conditions like obesity, fatty liver disease and T2D, immune cells withstand changes such as the recruitment of M1-polarized macrophages, which display a more proinflammatory phenotype and secrete proinflammatory cytokines such as TNF-α,IL-1, IL-6, IL-12 and C-reactive protein [94,105,106,107].