CD4 and obesity due to melanocortin 4 receptor deficiency: Consistent with the previous evidence, obesity-induced inflammation is a low-grade chronic inflammation that is characterized by pro-inflammatory cells that include macrophages, neutrophils, Th1 CD4 + T cells, CD8 + T cells, natural killer T cells, and B-cells that infiltrate AT, thus playing a crucial role in insulin resistance and T2DM [41].