In summary, treatment with L-Kyn appears to have exerted a predominant anti-inflammatory effect on PCM, mainly due to the early increased expression of AhR and IDO that controlled the fungal load and established a low expression of activation molecules by myeloid cells, a predominant expansion of plasmacytoid DCs and an increased differentiation of Foxp3+ Treg cells. The gene discussed is IDO1; the disease is paracoccidioidomycosis.