A PROSPECTIVE-STUDY OF FACTORS DETERMINING THE OUTCOME OF UNRELATED MARROW DONOR SEARCHES - REPORT FROM THE INTERNATIONAL MARROW UNRELATED SEARCH AND TRANSPLANT STUDY WORKING GROUP ON BEHALF OF COLLABORATING CENTERS

Outcomes of searches for unrelated bone marrow donors were analysed to identify factors influencing the probability of identifying an HLA-ma tched donor and proceeding to an unrelated donor bone marrow transplan t (UD-BMT). Between March 1989 and January 1991, 649 unrelated marrow donor searches were entered into the study. Searches were referred fro m transplant centres in Europe and North America to the Anthony Nolan Research Centre panel and/or the British Bone Marrow and Platelet Dono r Panel, two predominantly Caucasian donor registries. Patient immunog enetic and clinical characteristics were documented on study search re quest forms and search outcomes were monitored at the donor registry. Data were analysed using proportional hazards regression. Major factor s predicting favourable search outcomes were patient common Caucasian HLA phenotype and Caucasian ethnic group. Probability of search failur e was increased by advanced disease, rare Caucasian HLA phenotype and referral to the smaller registry. Search failure frequently occurred a t the mixed lymphocyte reaction stage. This study illustrates the rela tive roles of clinical, immunogenetic and registry factors in determin ing the outcome of searches. The information may be used to devise str ategies to locate HLA-matched donors for a higher proportion of patien ts for whom UD-BMT is the preferred treatment.