Pre‐existing anti‐HLA antibodies negatively impact survival of pediatric aplastic anemia patients undergoing HSCT

ABSTRACT Graft failure and survival are major problems for aplastic anemia patients undergoing hematopoietic stem cell transplantation (HSCT). Previous studies showed that anti-HLA antibodies negatively impact graft failure in HSCT. This retrospective study of 51 pediatric patients with acquired aplastic anemia who underwent allogeneic-HSCT at a single institution between 2006 and 2012 investigated the influence of anti-HLA antibodies on the outcome of HSCT. Serum samples collected before HSCT were tested for the presence of anti-HLA antibodies. Pre-existing anti-HLA antibodies were detected in 54.9% (28/51) of patients, among whom 39.2% (20/51) had anti-HLA class I antibodies. Anti-HLA antibodies were associated with worse 5-year survival (78.6% vs 100%, p=0.021) and higher treatment-related mortality (21.4% vs 0%, p=0.028) compared with antibody-negative patients. Anti-HLA class I antibody-positive patients had poorer 5-year survival (75.0%) than anti-HLA class I&II antibody-positive and -negative patients (87.5% and 100.0% respectively, p=0.039). Presence of anti-HLA class I antibodies (p=0.024) and older age (10yrs or more) (p=0.027) significantly increased the risk of post-HSCT mortality. Pre-existing anti-HLA antibodies negatively affect the outcome of HSCT in pediatric aplastic anemia patients. Routine testing for anti-HLA antibodies concurrent with efficient treatment should be conducted prior to HSCT.