Because IDO1 levels in women who cleared their infection post antibiotic treatment (PAT) did not correlate with the low kyn/trp ratios, we hypothesized that perhaps IDO1 is upregulated by a different mechanism, such as the long-term tolerogenic effect found in pDCs, in response to a synergistic effect with TGF-β1, which is independent of its enzymatic activity [29]. This evidence concerns the gene TGFB1 and infection.