IL17A and obesity due to melanocortin 4 receptor deficiency: In concert with the similarity in lesion size (Fig 6B), IL-17R-/- mice did not show increased accumulation of CD45+ cells (leukocytes) in auricular draining lymph nodes (Fig 6D), suggesting that IL-17 signaling was needed for the increase in lymph node leukocyte numbers and for lesion formation during obesity.