Impact Of Donor Choice On Pediatric Day +100 Transplant Mortality: The PBMTC Experience 2002-2004

A genotypically matched sibling is almost universally the preferred donor source for pediatric patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). Some patients lacking a matched sibling donor will have a matched or mismatched related donor identified. It is not clear whether in this setting a family donor is preferable to an unrelated donor. Using the data base of the Pediatric Bone Marrow Transplant Consortium from 2002-2004 we evaluated 100 day mortality in 2696 patients<22 years of age receiving an non-syngeneic HSCT. Results: The observed 100 day mortality for matched sibling donors (n=624) was 9.5%, for other matched family donors (n=41) 12% and for mismatched sibling donors (n=89) 19%. Univariate analysis assigning a value of 1 for the 100 day mortality reported for 939 autologous transplants from this cohort was performed. There was no difference in mortality seen in patients transplanted from a matched sibling donor (OR=1.2, NS) or other matched family donor (OR=1.6, NS). The use of mismatched sibling donors and matched or mismatched unrelated donors resulted in a significant increase in Day 100 mortality (OR=2.8-4.1, p<0.005). However, in multivariate analysis incorporating 47 independent variables there was a trend toward increased mortality as donor disparity increased. Compared to those undergoing autologous transplant, patients receiving a transplant from a matched sibling donor had an OR of 2.3 (95% CI, 1.2-4.5), other matched family donor 3.6 (95% CI, 1.2-11.3), mismatched sibling donor 4.5 (95% CI, 2-10.2), matched unrelated donor 6.4 (95% CI, 3.9-16.6) and mismatched unrelated donor 7.8 (95% CI, 3-14.5). Conclusion: When an HLA matched sibling donor is not available, the differences in acute mortality between alternative donor options may be outweighed by other donor/patient considerations. The use of a mismatched sibling donor or unrelated donor compared to a matched family donor may confer an increased risk that should be considered in the context of individual patient circumstances.