Identification of the novel allele HLA-B*1546 which belongs to the serological B72 typo: implications for bone marrow transplantation

The identification of the novel allele HLA-B*1546, which has serological B5 0 and B72 reactivity, was found in two members of a family of Turkish origi n. In the sequence analysis the new allele differs from B*1501 by four nucl eotides in exon 2. Its structure suggests that it may have originated by ge ne conversion with B*40, B*41, B*44, B*4501, B*47, B*4901 or B*50. At the p rotein level, the new allele has three amino acid differences compared to B *1501. Sequence alignment demonstrates that amino acid residue 46 is crucia l for serological B72 reactivity, Due to substantial differences with other B*15 variants a possible mismatch may impair clinical outcome of bone marr ow transplantation.