Flu exposure-response relationship. (A-C) Lines depict the estimated event probability (y-axis) at the given Flu AUC (x-axis), for NRM (A), graft failure (B), and relapse (C). (D) Symbols correspond to the estimated event probability (y-axis) of sequential patients at their cumulative Flu AUC (x-axis). Red stars indicate the occurrence of NRM; blue triangles indicate graft failure; green triangles indicate relapses, and the black stars correspond to patients without events. The shaded areas depict the 95% CIs. Displayed event probabilities correspond to a patient at the median age of 35 years, diagnosed with leukemia/lymphoma and no prior HCT. P values (A-C) are calculated by likelihood ratio test using backward deletion from the full regression model. ^aAdjusted for age (polynomial spline, 3 degrees of freedom) and prior allogeneic transplants (yes/no). ^bAdjusted for indication (malignant/benign). ^cAdjusted for age (polynomial spline, 3 degrees of freedom), indication (lymphoma/leukemia, benign, myelodysplastic syndrome, plasma cell disorder), and prior allogeneic transplants (yes/no). *Significant at level P < .05. ***Significant at level P < .001.