Prophylactic NAC intervention reduced the incidence of PGF and PT in the EC < 0.1% group by improving defective BM ECs. The cumulative incidence of PGF and PT at +2 months (A), platelet engraftment (B), neutrophil engraftment (C), and aGVHD (D) within 100 days post-HSCT, NRM (E) and estimated OS (F) at +10 months post-HSCT, as well as the dynamic reconstitution of BM EC percentages (G), EC ROS levels (H), CD34⁺ cell percentages (I), and CD34⁺ cell ROS levels (J) were compared between the EC < 0.1% group and the EC ≥ 0.1% group in the first clinical trial and the EC < 0.1% with prophylactic NAC intervention group and the EC ≥ 0.1% group in the second clinical trial. Cumulative incidence curves were analyzed using a competing risk setting and were compared using the Gray test. Probabilities of OS were estimated with the Kaplan-Meier method and were compared using the log-rank test. The data are expressed as the mean and SEM. P < .05 was considered statistically significant and values are provided in the figure.