... abnormalities in the kynureninepathway of tryptophan degradation.Keywords: human, fibroblast, kynurenine pathway, gene expression, cytokineIntroductionThe kynurenine pathway (KP) is the main route of ... encodingindoleamine 2,3-dioxygenase, kynureninase or 3-hydroxyanthranilic acid oxygenase and decreases in the levels of transcripts encoding tryptophan 2,3-dioxygenase, kynurenine aminotransferases ... the first and rate-limiting step of this pathway and is highly induced by the pro-inflamma-tory cytokine interferon (IFN)-g [22,23]. However, it isnot clear if pro-inflammatory cytokines affect...