Obesity seems to disturb this scenario; after 6 weeks of HFD, bone marrow malfunction is induced by a mechanism depending on LPS originated from bacteria (translocated from the gut to the bloodstream) that stimulate, via TLR4, myelopoiesis instead of lymphopoiesis (33). This evidence concerns the gene TLR4 and obesity due to melanocortin 4 receptor deficiency.