FURTHER DIVERSITY AT HLA-A AND -B LOCI IDENTIFIED IN BLACK POTENTIAL BONE MARROW DONORS.
AM Little1, A McWhinnie1, ST Cox1, RP Koester2, U. Heine2, R Holman1 and JA Madrigal1, 1Anthony Nolan Research Institute, London and 2LabCorp, Burlington, NC.
Two novel HLA-A and three novel HLA-B alleles were identified within a group of black individuals whom had been recruited as potential donors for The Anthony Nolan Bone Marrow Trust Register. HLA typing was performed on DNA extracted from peripheral blood mononuclear cells using sequence specific oligonucleotide (SSO) probes (Lifecodes) for HLA-A and -B loci. Eight individuals analysed exhibited hybridisation patterns for which a type could not be assigned. DNA from these individuals was further typed by two methodologies: direct sequencing of PCR products and reference strand conformational analysis (RSCA). The direct sequencing results allowed the identification of new alleles but did not allow confirmation of the cis/trans orientation of the novel sequence motifs identified. RSCA analysis confirmed the results obtained by SSO and direct sequencing and in addition confirmed the cis/trans orientation of the new sequences. One individual possesses a new A*30 allele and two individuals possess an identical new A*74 allele. The three novel HLA-B alleles were identified in each of three individuals; B*08new, B*15new and B*45new. For the remaining two samples, the recently defined A*2612 allele was identified. At present caucasoid individuals, and therefore caucasoid phenotypes are predominantly represented on the various different volunteer bone marrow donor registries. The examples presented here highlight the potential for identification of further polymorphisms within the HLA system as more individuals from the much needed ethnic minorities are recruited onto bone marrow donor registers.