[Therapeutic efficacy of hematopoietic stem cell transplantation for Wiskott-Aldrich syndrome in 60 children].

Objective: To evaluate the therapeutic efficacy of hematopoietic stem cell transplantation (HSCT) for Wiskott-Aldrich syndrome (WAS), and to analyze the factors related to the outcomes. Methods: The clinical data of 60 children with WAS received HSCT in Shanghai Children's Medical Center from January 2006 to December 2020 were retrospectively analyzed. All cases were treated with a myeloablative conditioning regimen with busulfan and cyclophosphamide, and a graft-versus-host disease (GVHD) prevention regimen based on cyclosporine and methotrexate. Implantation, GVHD, transplant-related complications, immune reconstitution and survival rate were observed. Survival analysis was performed by Kaplan-Meier method, and Log-Rank method was used for univariate comparison. Results: The 60 male patients had main clinical features as infection and bleeding. The age at diagnosis was 0.4 (0.3, 0.8) years, and the age at transplantation was 1.1 (0.6, 2.1) years. There were 20 cases of human leukocyte antigen matched transplantation and 40 mismatched transplantation; 35 patients received peripheral blood HSCT, and 25 cord blood HSCT. All cases were fully implanted. The incidence of acute GVHD (aGVHD) was 48% (29/60) and only 2 (7%) developed aGVHD of grade Ⅲ; the incidence of chronic GVHD (cGVHD) was 23% (13/56), and all cases were limited. The incidence of CMV and EBV infection was 35% (21/60) and 33% (20/60) respectively; and 7 patients developed CMV retinitis. The incidence of sinus obstruction syndrome was 8% (5/60), of whom 2 patients died. There were 7 cases (12%) of autoimmune hemocytopenia after transplantation. Natural killer cells were the earliest to recover after transplantation, and B cells and CD4⁺T cells returned to normal at about 180 days post HSCT. The 5-year overall survival rate (OS) of this group was 93% (95%CI 86%-99%), and the event free survial rate (EFS) was 87% (95%CI 78%-95%). EFS of non-CMV reactivation group is higher than that of CMV reactivation group (95% (37/39) vs.71% (15/21), χ²=5.22, P=0.022). Conclusions: The therapeutic efficacy of HSCT for WAS is satisfying, and the early application of HSCT in typical cases can achieve better outcome. CMV infection is the main factor affecting disease-free survival rate, which can be improved by strengthening the management of complications.