LEP and obesity due to melanocortin 4 receptor deficiency: As multiple immune factors, particularly inflammatory cytokines (such as IL-1, IL-6, and TNF-α) and adipokines (such as leptin and adiponectin), have been well-addressed elsewhere in obesity, we highlight the regulatory role of the IFN system in immunometabolic regulation in the scenario of viral infectobesity [4,11,12,30].