Umbilical cord blood transplantation in Wiskott Aldrich syndrome

Objective: To report the use of umbilical cord blood (UCB) stem cell transplantation in Wiskott Aldrich syndrome (WAS) when a matched sibling donor was unavailable. Methods Three children with WAS received unrelated umbilical cord blood stem cell transplantation after a preparative regimen for the treatment of combined immunodeficiency diseases. The patients ranged in age from 1.9 to 7.9 years. The cord blood units were 4/6 HLA antigen matches in 2 children and 5/6 in 1 child, with molecular HLA-DR match in all 3 children. Results The time for neutrophil engraftment (ANC >500/mm(3)) was 11 to 16 days, and the average time for platelet engraftment was 36 to 49 days. One patient had no evidence of GvHD, 1 patient grade I, and 1 patient grade II. No patient had chronic GvHD. The patient with grade II GvHD also had gut involvement. Immunologic reconstitution demonstrated that cord blood stem cell transplantation resulted in consistent and stable T-, B-, and NK-cell development. Functional B-cell antibody responses revealed that 2 of the patients in whom IVIG has been discontinued had low detectable antibody responses to tetanus and diphtheria toxoid immunizations at 18 to 24 months after transplantation. Conclusions Unrelated umbilical donor cord blood is an alternative source of stem cells for transplantation in children with WAS when a suitable HLA-matched donor is not available. Benefits of UCB include rapid and reliable recovery of immune function, low risk of GvHD and low viral transmission rate.