The outcomes of isoniazid prophylaxis in LTBI high-risk pediatric patients undergoing hematopoietic stem cell transplantation.

BACKGROUND: Tuberculosis (TB) infection poses a significant risk to patients undergoing hematopoietic stem cell transplantation (HSCT), particularly those with latent TB infection (LTBI). Despite the recognized vulnerability of these patients, data on TB prophylaxis and its outcomes in pediatric HSCT recipients remain limited.

METHODS: We conducted a retrospective study of 714 pediatric HSCT recipients at Shenzhen Children’s Hospital from January 2018 to December 2021. Patients were categorized into LTBI high-risk and low-risk groups based on positive interferon-gamma release assay (IGRA) results and radiological findings indicative of prior TB infection. The high-risk group received isoniazid (INH) prophylaxis, while the low-risk group did not receive routine TB prophylaxis. Patient outcomes, including TB incidence, drug toxicity, and post-HSCT complications, were monitored over two years.

RESULTS: The high-risk group comprised of 69 patients, and the low-risk group included 620 patients. No significant differences were observed between the groups regarding patient characteristics, HSCT type, or donor source. Over the follow-up period, no confirmed TB cases occurred in the high-risk group receiving INH prophylaxis, whereas one patient (0.31%) in the low-risk group developed TB. Mild hepatic toxicity (grade 1) was observed in 27.54% of patients in the high-risk group, with one case of grade 3 toxicity (1.45%) requiring INH discontinuation. No severe renal toxicity or fatal adverse events were reported. Post-HSCT complications included acute graft-versus-host disease (11.59%), chronic graft-versus-host disease (13.04%), and invasive fungal infections (4.35%), with no significant differences in outcomes between the groups. Full graft chimerism was achieved in 98.55% of patients, and no deaths occurred during the study period.

CONCLUSIONS: INH prophylaxis effectively prevented TB reactivation in LTBI high-risk pediatric HSCT recipients without significant adverse events. A risk-based stratification approach to TB prophylaxis is both safe and effective, minimizing unnecessary drug exposure while protecting vulnerable patients.