CXCL12 and obesity due to melanocortin 4 receptor deficiency: We speculate that because of the fact that SDF-1 levels are relatively high in human AT and are strongly associated with selected complement-derived molecules, it is possible that actions of these molecules may influence and promote the homing of immune cells and hematopoietic SCs in human AT, and thereby contribute to development of “obesity-associated” inflammation within AT environment.