ABSTRACT Background Infection is a common complication following umbilical cord blood transplantation (UCBT), yet comprehensive data on pediatric patients with inborn errors of immunity (IEIs) in China are scarce. This study aimed to characterize infection profiles and their prognostic implications in this population. Methods We retrospectively analyzed 165 IEIs patients undergoing UCBT between January 2015 and June 2020. The post‐transplantation period was divided into early (≤ 30 days) and middle (31–100 days) stages. Results Within 100 days, 115 patients (69.7%) experienced 217 infection episodes. Engraftment failure was an independent predictor of infection risk within 100 days (OR = 2.97, p = 0.04). Low pre‐transplantation IgM levels and graft‐versus‐host disease (GVHD) prophylaxis with calcineurin inhibitors (CNIs) plus mycophenolate mofetil (MMF) increased early‐stage infection risks ( p < 0.05). Infections at the middle stage were correlated with Grade II–IV acute GVHD ( p = 0.03). Bloodstream infections (BSIs) were linked to CNIs combined with MMF and lower total nucleated cell counts in cord blood ( p < 0.05). Early‐stage infected group exhibited significantly poorer survival versus uninfected and middle‐stage groups ( p < 0.001). Patients without bacterial infections had higher survival rates than those with carbapenem‐resistant or non‐resistant infections ( p < 0.05). BSIs were associated with poor prognosis ( p < 0.05), while cytomegalovirus infection showed no significant survival impact ( p = 0.05). Conclusions Infections are highly prevalent in IEIs children post‐UCBT, with early‐stage events and BSI portending poorer outcomes. These findings advocate for risk‐stratified surveillance and preemptive strategies in high‐risk subgroups. image
Wei et al. (Fri,) studied this question.