CD1D and obesity due to melanocortin 4 receptor deficiency: Pathological roles of NKT cells in obesity were also reported by Satoh et al. 11 in Cd1d−/− mice, but these investigators found no difference in the metabolic parameters between Traj18−/− and WT B6 mice on HFD feeding, arguing for a pathogenic role of type 2 rather than type 1 iNKT cells.