TRAJ18 and obesity due to melanocortin 4 receptor deficiency: Pathological roles of NKT cells in obesity were also reported by Satoh et al. (38) in Cd1d1−/− mice; however, no difference in the metabolic parameters between Traj18−/− and WT B6 mice on an HFD was observed in their study, arguing for a pathogenic role of type II NKT rather than iNKT cells in these pathologies.