MRD detection in clinical samples after allogeneic HSCT. (A) Representative MRD detection in 2 patients with (patient 1) or without (patient 10) major response post AZA treatment. For MRD quantification different methods were applied: CD34⁺ DC-based analysis (blue dots); NGS on FACS-enriched CD34⁺ PB cells (red dots) or whole-blood samples (green dots). For CD34⁺ DC analysis, values <80% were considered MRD positive. For NGS-based analysis, an increase in mutant alleles >0.01% was classified MRD positive. (B) Follow-up intervals after allo-HSCT and MRD detection (coded by color) in 29 patients with MRD-guided preemptive AZA treatment. An improvement of MRD detection by NGS-based analysis of CD34⁺/CD117⁺ PB cells (as compared with both other MRD methods tested) is indicated by the light gray bars. (C) MRD detection before AZA treatment. Box plots represent median values with interquartile range; box whiskers represent minimum to maximum values.