IL17A and obesity due to melanocortin 4 receptor deficiency: In obesity, the adipose immune system is dysregulated and replaced by inflammatory cells (for example, M1 macrophages, Th1, Th17, and CD8+ T cells) (13, 38) that secret proinflammatory cytokines such as IL-1β, IL-6, IL-17, and IFNγ (19– 21).