We evaluated the impact of busulfan pharmacokinetic (Bu-PK) monitoring on toxicity and outcomes in pediatric patients undergoing busulfan-based myeloablative HSCT for benign (n = 221) and malignant diseases (n = 15) at our center in India (January 2023-December 2025). Bu-PK using liquid chromatography-tandem mass spectrometry was available to 93 patients whose toxicity and outcomes were compared to 143 patients in whom Bu-PK was not done. Once-daily intravenous busulfan was administered over 3 h. Median busulfan dose administered was 105.3 (IQR 93.2-127.6)% with a wide range of 41.7%-213.1% of the standard weight-based dosing, with no added toxicity in those receiving doses >125% of the weight-based dose. Infections, particularly CMV reactivation, were more frequent in the Bu-PK group with no increase in mortality. Mixed chimerism was significantly lower in the Bu-PK group (4.6% vs. 24.1%), with an 84% reduction in odds (OR = 0.16, 95% CI 0.05-0.43, p < 0.001). The implementation of monitoring was crucial for overcoming pharmacokinetic variability, reducing mixed chimerism, while maintaining an acceptable overall toxicity profile in our pediatric cohort.
Exposure to high altitude can lead to hypobaric hypoxia, which triggers adaptive hematological responses in humans. We examined clinical variation in pediatric immune thrombocytopenia (ITP) across two attitudinally distinct regions and evaluated the influence of altitude on disease outcomes. The study included 156 Chinese Han children with ITP: 68 in the high-altitude group (ALT, Xining City) and 88 in the sea-level group (SEA, Ningbo City). Children in the ALT group were older and presented with higher bleeding grades compared to those in the SEA group. Multivariate logistic regression showed that older age was associated with a significantly greater risk of a prolonged disease course. In contrast, patients who achieved complete response (CR) within 7 days of treatment, as well as those in the ALT group, were less likely to develop a prolonged course. These findings highlight altitude as a potential modifier of pediatric ITP outcomes and warrant further investigation into the underlying mechanisms.
