Prophylactic NAC intervention improved the dynamic reconstitution of BM EPCs in the EC < 0.1% group to similar levels relative to those in the EC ≥ 0.1% group. (A) Immunofluorescence staining of EPCs in BM trephine biopsies. Mouse anti-human CD34 (green) and rabbit anti-human CD133 (red) were incubated to identify the BM EPCs. 4′,6-Diamidino-2-phenylindole (DAPI; blue) was used to stain the nucleus. In situ histological analyses of BM trephine biopsies showed the dynamic reconstitution of double-positive (merged in yellow) CD34 (green)- and CD133 (red)-stained EPCs pre- and post-HSCT between the 2 groups of patients (scale bars represent 50 μm). The dynamic reconstitution (left panel) and statistical analyses (right panel) of BM EPC percentages (B) and EPC ROS levels (C) were analyzed by flow cytometry in the EC < 0.1% with prophylactic NAC intervention group at −14 days and 0 days pre-HSCT and +1 month and +2 months post-HSCT relative to the EC ≥ 0.1% group in the second clinical trial. The data are expressed as the mean and SEM. Statistical analyses were performed using 1-way ANOVA for comparisons among the groups. Subject variables were compared using the χ² test for categorical variables and the Mann-Whitney U test for continuous variables. P < .05 was considered statistically significant and values are provided in the figure. *P < .05.