Direct relationship between donor-recipient high resolution HLA class I matching and survival in 79 children transplanted with an unrelated bone marrow in a single center

Since September 1996 until September 1999, HLA genomic typing for class I alleles (at low resolution level) and class II (at high resolution) has been performed to match unrelated bone marrow donors for our patients, adults and children. Since September 1999 to nowadays, HLA class I molecular typing at four digits was added to our operative internal standards. One year later, we estimated the effects of this innovation in terms of transplant related mortality, comprehensive of GVHD and relapse, with respect to the past three years. We started examining a group of 49 children affected by haematological disorders (36 malignant and 13 non-malignant), consecutively transplanted in a single center with and unrelated donor from September 1996 until September 1999, and a second group of 30 children (17 with malignant and 13 with nonmalignant haematological diseases) who underwent an unrelated BMT since September 1999 to September 2000. To standardize the observations, only the first year of follow-up was examined for all the cases. The survival was of 51% (25/49) in the first group of patients while of 76.6% (17/30) in the second one, p=0.023. Considering the mortality rate in function of recipients' disease we observed that, in patients affected by malignant diseases and belonging to the first group, it was of 58.8% (21/36) significantly higher than that observed in the second group of oncohaematologic patients: 29.9% (5/17), p=0.049. As far as relapse was concerned, it occurred in 6/36 (16.6%) patients in the first group and in 3/17(17.6%) in the second group of babies with malignant haematological diseases. No statistically significant differences were found in children affected by non-malignant disorders either in terms of mortality or relapse rates. Our results show that high resolution HLA class 1 matching could represent an important way to improve the course of the unrelated BMT especially in children affected by malignant haematological disorders and suggest that this procedure should be done from now on for unrelated BMD selection. Further study in the adult cohort is in progress to confirm this observation. © 2001 Blackwell Science Ltd,