No Effect Of Birth Order On Relapse, Graft-Versus-Host Disease Or Transplant Related Mortality In Matched Sibling Donor Bone Marrow Transplant In Pediatric Patients With Leukemia

Introduction: The impact of birth order of patient and donor in matched sibling hematopoietic stem cell transplantation (HSCT) has not been fully defined. It has been postulated that as a result of fetomaternal trafficking donors who are younger than the transplant patient may develop in utero tolerance to patient cells. A large registry study of adult and pediatric patients found that using a donor younger than the recipient (R>D) was associated with decreased acute GVHD; single center studies found this to be correlated with decreased relapse and improved overall survival as well. We hypothesized that in pediatric patients with hematologic malignancies and a presumed low incidence of acute GVHD that birth order would not have an impact on relapse incidence.