Cumulative incidence functions of the training and validation cohorts. A higher cumulative incidence of the development of RF for those with high biomarker levels (red line) is seen on day 14 post-HCT compared with those with levels below the cut-point chosen by Youden’s index (blue line). High levels of ST2, WFDC2, IL-6, and TNFR1 predicted a statistically significant increase in the development of RF within 100 days posttransplant.