CXCL16 and obesity due to melanocortin 4 receptor deficiency: In obesity, CXCL16 positively regulates the following immune cell infiltrations as shown by correlation analysis between diagnostic biomarkers and immune cells: type 1 T helper cells, T-follicular helper cells, regulatory T cells, natural killer T cells, monocytes, MDSC, macrophages, immature B cells, gammadelta T cells, effector memory CD4 T cells, CD56dim natural killer cells, activated dendritic cells, activated CD4 T cells and activated B cells (Fig. 7B).