Unrelated Donor Hematopoietic Cell Transplantation: Factors Associated with a Better HLA Match

The impact of non-HLA patient factors on the match of the selected unrelated donor (URD) for hematopoietic cell transplantation (HCT) has not been fully evaluated. National Marrow Donor Program (NMDP) data for 7486 transplants using peripheral blood stem cells (PBSCs) or bone marrow from years 2000 to 2005 were evaluated using multivariate logistic regression to identify independent non-HLA patient factors associated with completing a more closely matched URD transplant. Advanced (intermediate- and late-stage) disease was significantly associated with an increased likelihood of transplant using a less-matched (partially matched or mismatched) donor. Additionally, Black patients were 2.83 times, Asian patients 2.05 times, and Hispanic patients 1.73 times more likely to have a less-matched HCT donor than Caucasian patients. Younger patients, HCT at lower volume centers, and in earlier years had significantly higher likelihood of having a less HLA matched URD transplant. Our analysis provides encouraging evidence of HLA matching improvement in recent years. Initiating a patient's URD search early in the disease process, especially for patients from non-Caucasian racial and ethnic groups, will provide the best likelihood for identifying the best available donor and making informed transplant decisions.