AHR and multiple sclerosis: The strong and significant decrease of galactosylceramide (GalCer) concentrations measured by UPLC-MS in the optic nerve of AhR-KO mice suggest that modified ceramides might represent potential biomarkers of inflammatory diseases in the CNS as also suggested by Mayo et al. who characterized increased levels of lactosylceramide (LacCer) during chronic experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS)24.