Patient MRD-based risk stratification and quantitative comparison of the MRD markers. (A) Alluvial plot of the risk stratification of all patients based on their qPCR or NGS MRD levels at day 33 with the threshold MRD value of 10−3 used for HR MRD stratification in the AIEOP-BFM ALL 2009 protocol. A change in assignment to a higher risk group based on the NGS MRD result occurred for 16 patients (3.7%) from the SR to the MR group, and for 3 patients (0.7%) from the MR to the HR group. An opposite change from the MR to the SR group occurred for 64 patients (14.8%) and from the HR group to the MR group for 18 patients (4.2%). (B) Comparison of the MRD levels as measured by qPCR (x-axis) or NGS (y-axis). All markers of patients that relapsed are marked in red. NEG, negative.
