While it has been shown that CD1d disruption both globally18, 19 and selectively in adipocytes ameliorates the development of obesity, other research groups have reported that CD1d disruption enhances the development of obesity and that iNKT cells in adipose tissue produce IL-4 and IL-10 that induce M2 macrophages15, 16, 17. This evidence concerns the gene IL4 and obesity due to melanocortin 4 receptor deficiency.