ACKR1 and obesity due to melanocortin 4 receptor deficiency: Lastly, as we focused on IL-22 and DARC+ cell generation, future experiments to define the functional role of these cells in obesity or adipogenesis should be conducted with respect to the differences in surface marker levels (e.g., CD16hiDARC+ vs. CD16IntDARC+), ontogeny, developmental changes in DARC+ cells, and changes in the Treg cell levels in adipose tissue.