Prognostic significance of kynurenine catabolites. (A) Time courses of urinary levels of KYN as a function of TRM. Data are the mean ± SE of the molar ratio of KYN to creatinine (μmol/mmol) for both surviving patients (n = 41) and those who died of GVHD and associated complications (n = 10) as a function of time; differences were significant: P < .05 for day 28 and P < .01 for days 42 and 90. (B) Time courses of urinary levels of QA as a function of TRM. Date are the mean ± SE of the molar ratio of urinary QA to creatinine (μmol/mmol) for both surviving patients (n = 41) and those who died of GVHD and associated complications (n = 10) as a function of time; differences were significant: P < .01 for day 28 and P < .001 for days 42 and 90. (C) Cumulative nonrelapse mortality as a function of urinary KYN levels on day 42. Patients with KYN levels above median had significantly (log-rank, P = .005) increased TRM compared with patients with levels below median.