IL6 and obesity due to melanocortin 4 receptor deficiency: The secretion of inflammatory cytokines (IL-1, IL-6, and TNF-α) from infiltrated immune cells, mainly macrophages, is associated with obesity [47–49] and may exert control over apoptotic mediators through upstream regulation of cIAP2 and FLIP involving NF-κB, a transcription factor that is activated by cytokines secreted in obesity (Fig. 1).