Prospective analysis of LAPs in patient samples. (A) Correlation of leukemia detectability based on gating performed with standard MRD markers and panels including experimental markers. To gate the leukemic population, 9 candidate markers were used in combination with CD19 and CD45 antibodies for a total of 69 tests performed on 20 MRD cases from day15. The percentage of leukemic cells was calculated in respect to all nucleated events as determined by Syto 41 or Syto16 stainings and compared with levels of leukemia determined by standard gating based on CD19, CD45, and CD10 expression. R indicates Pearson correlation score. (B) Differential expression of experimental markers between leukemia cells and residual normal lymphoid cells at diagnosis and in paired MRD cases. The difference in MFI (arbitrary units) between leukemia cell population and nonmalignant CD19+ cells within the same sample measured at diagnosis (Dx) and in MRD cases at day 15 of treatment (M) is represented as a color-coded plot. In total, 187 stainings were performed for experimental markers at both time points in 34 matched ALL cases from 2 cohorts. Depending on material availability, different numbers of markers were assigned to a given sample (number of patients screened for each individual marker at both time points: CD157, 24; CD97, 27; CD63, 19; CD305, 15; CD18, 27; CD102, 22; CD317, 12; CD217, 10; and CD31, 31). Cases in which the experimental marker expression in both leukemic and nonmalignant cell population was below the positivity threshold established for each cohort are not displayed in the graph. Differential expression of CD58 is presented for 9 matched cases as a control.