Successful Umbilical Cord Blood Transplantation in Children with Leukocyte Adhesion Deficiency Type I.

Background: This study aims to investigate the efficacy and safety of umbilical cord blood transplantation (UCBT) without serotherapy for treating children with leukocyte adhesion deficiency type I (LAD-I). Methods: Clinical characteristics and data of five children with LAD-I who underwent UCBT at our hospital between September 2016 and September 2018 were retrospectively analyzed. Results: Five (two boys and three girls) patients with LAD-I were included. The median age at UCBT was 9 months (range, 8 to 32 months). The same myeloablative conditioning regimen was administered for each patient and included busulfan, fludarabine, and cyclophosphamide. HLA matching of patients and umbilical cord blood was 8/10 to 10/10. The median dose of total nucleated cells (TNC) infused was 10.2x10(7)/kg (range, 4.5x10(7) to 20.6x10(7)/kg) and the median dose of CD34+ cells was 3.2x10(5)/kg (range, 1.9x10(5) to 5.7x10(5)/kg). The median time of neutrophil engraftment was 20 days (range, 13 to 28 days). The median time of platelet engraftment was 36 days (range, 32 to 56 days). All patients received complete donor chimerism (CDC). Four of the five patients developed grade II-IV acute graft-versus-host disease (GvHD). The median follow-up time after transplantation was 19 months (range, 8 to 38 months). Four of the patients survived and achieved complete clinical remission. The other patient died of bronchiolitis obliterans 8 months after UCBT. Conclusions: UCBT is an effective treatment method for LAD-I patients. Also, severe LAD-I patients should undergo stem cell transplantation as early as possible.