CCL2 and obesity due to melanocortin 4 receptor deficiency: Since obesity correlates with low grade inflammation and obese adipose tissue can be heavily infiltrated by immune cells, the mRNA levels of specific immune cell markers (Itgam and Il1b) and of tissue chemokines (Il6 and Ccl2) were quantified in pWAT, eWAT and iWAT (Fig. 1G-J).