[Significance of confirmatory testing of HLA system in unrelated haematopoietic stem cell donors]

Haematopoietic stem cell transplantation is a standard curative therapy for some acquired haematological diseases and inherited metabolic and immunological disorders. The HLA compatibility in five loci (HLA class I -A, -B and -C and HLA class II -DRB1 and -DQB 1) of the donor/recipient pair is a prerequisite for the success of haematopoietic stem cell transplantation which represents a process of adoption donors immunity.

HLA is the most polymorphic system in the human genome and this polymorphism is exactly detected by molecular genetics methods on DNA level only. In period of 2001-2004 we performed confirmatory testing of 366 unrelated haematopoietic stem cells donors from Czech and foreign registers for 256 patients. Only 16% of the donors completely matched the patients in all HLA loci. We detected HLA mismatches in the samples of 81% patient/donor pairs but these results were consonant with previous results from registers. 3% of confirmatory samples were discrepant with previous registry data.

Despite of increasing number of available unrelated haematopoietic stem cell donors and the quality of registry HLA typing the possibility of finding the completely match donor is still limited.