Outcome of unrelated bone marrow donor searches in 174 children resulting in 45 patients transplanted in the HLA-matched and -mismatched situation.

The aim of the study was to evaluate the outcome of unrelated bone marrow donor (UBMD) searches initiated for 174 children between 1986 and 1997. Seven patients were registered twice so that a total of 181 UBMD searches took place. At the time of registration, patients suffered from hematological malignancies (n = 121), non-malignant hemopathies (n = 26) and inborn errors (n = 34). Forty-five of the patients (26%) were given transplants from unrelated donors of whom 26 (58%) were HLA-mismatched transplants. Our strategy accepted HLA mismatches at the time of donor selection, using Thymoglobuline as part of the conditioning regimen. Of the 45 patients given unrelated donor transplants, overall survival was 60% at 3 years and concerned 27 patients of whom 14 were from HLA-mismatched donors. Disease-free survival for hematological malignancies was 65% in HLA-matched transplants and 50% in HLA-mismatched transplants. For some patients (16%) urgency led us to use alternative options: non-identical related donor (n = 14), autograft (n = 10), related cord blood transplant (n = 4). For others, UBMD searches were stopped because of favorable evolution (n = 29), death (n = 24), disease progression (n = 22) or other reasons (n = 21). By the end of the follow-up period, 88 patients had died (50%), 75 (43%) are currently alive with or without being transplanted of whom eight are still having active searches and 11 are no longer contactable. In conclusion, in severe disease in children, an immediate transplant from a partially matched donor might be preferable to a prolonged search for a full match. Consequently, this strategy increases the number of patients for whom a suitable donor can be found. We have chosen this option in order not to delay BMT; in so doing we have obtained encouraging results which include high overall survival, low incidence of acute GVHD grade III-IV and low percentage of relapse even in mismatched pairs.