Estimation of optimal donor number in Bone Marrow Donor Registry: Hong Kong's experience.

Better outcome for hematopoietic stem cell transplantation (HSCT) requires optimal matching between donor and recipient at the HLA-A, -B, -C, and -DRB1 loci. This study estimates the likelihood of identifying HLA matched donors in Hong Kong. 7595 volunteer unrelated Chinese donors at the Hong Kong Bone Marrow Donor Registry were typed with HLA-A, -B, -C and -DRB1 genotypes. The matching probabilities for 8/8 and 7/8 HLA match via the matching models were determined. Based on current 100,000 donors in the HKBMDR, the matching probabilities are 45% at 8/8 HLA match and 65% at 7/8 match. By increasing the registry to 200,000, the likelihoods of match become 54% and 73% at 8/8 and 7/8 match stringencies respectively. Our findings may be helpful in planning future donor recruitment and HLA typing. A cost-effective Bone Marrow Donor Registry with a larger pool of donors could increase chance of matching and the success of HSCT.