In MS, it has been shown that PwMS have lower urinary levels of kynurenine, a known immunosuppressive tryptophan metabolite, which was also negatively correlated with the Expanded Disability Status Scale (EDSS) score.118 In the CNS, Quintana et al. found that supplementation with tryptophan metabolites activated AhR on astrocytes leading to an increase in IFN-I signaling and attenuating EAE.119 Importantly, AhR agonists, including tryptophan metabolites were also reduced in PwMS.119 Interestingly, high tryptophan diet ameliorated EAE and reduced autoreactive T cell activation and migration. The gene discussed is AHR; the disease is myeloid sarcoma.