Fig. 2

Serum KYN and QUNA concentrations and KYN/TRP ratio in DILD, other lung diseases, and HC. A The KYN pathway. Major metabolic enzymes are written in italics. IDO, indoleamine 2,3-dioxygenase; KATs, kynurenine aminotransferases; KMO, kynurenine 3-monooxygenase; KYNU kynureninase, 3-HAO; 3-hydroxyanthranilate oxidase; QPRT, quinolinate phosphoribosyl transferase. B Serum concentrations of KYN and QUNA, and KYN/TRP ratio among sample groups are shown as box-and-whisker plots. The middle lines represent the median values and the whiskers represent the highest and lowest values. The results of the statistical comparisons are summarized in Table 2. DAD/DAD-mixed: DILD patients in acute phase with CT pattern of diffuse alveolar damage, OP: DILD patients in acute phase with CT pattern of organizing pneumonia, NISP: DILD patients in acute phase with CT pattern of nonspecific interstitial pneumonia: Other: DILD patients in acute phase with CT pattern other than DAD, OP and NSIP, DILD recovery: patients recovered from DILD, DILD-tolerant: the patient group taking similar medications to DILD group but without DILD onset, BP: bacterial pneumonia, NTM: nontuberculous mycobacteriosis, IIPs: idiopathic interstitial pneumonias, CTD: lung disease associated with connective tissue disease, COPD: chronic obstructive pulmonary disease, BA: bronchial asthma, HC: healthy control