Moreover, exogenous xenobiotic (e.g., BaP) or nutritional (e.g., indole-3-carbinole, I3C) but also endogenous AhR ligands (e.g., kynurenine, a product of tryptophan metabolism) can modulate innate and adaptive immunity, potentially resulting in either increased or decreased susceptibility to infection or cancer and may trigger autoimmune disorders and allergies (12). This evidence concerns the gene AHR and infection.