Recognition of a Caucasoid HLA ‐ B locus allele, B *44:55, in a T aiwanese/ C hinese bone marrow stem cell donor

Summary We detected a C aucasoid HLA ‐ B allele, HLA ‐ B *44:55, in a potential T aiwanese/ C hinese bone marrow hematopoietic stem cell donor during our routine HLA SBT (sequence‐based typing) practice. The sequence of B *44:55 varies with B *44:02:01:01 with one nucleotide in exon 2 at position 97 ( T ‐> C ), while it differs from B *44:03:01 with one nucleotide in exon 2 at position 97 ( T ‐> C ) and three nucleotides in exon 3 at residues 538–540 ( CTG ‐> GAC ). The nucleotide replacements caused one amino acid variation with B *44:02:01:01 at residue 9 ( Y ‐> H ) and two amino acid variations with B *44:03:01 at residue 9 ( Y ‐> H ) and residue 156 ( L ‐> D ). The formation of B *44:55 is probably the result of a nucleotide substitution involving B *44:02:01:01 at position 97 ( T ‐> C ). The Taiwanese/Chinese donor with B *44:55 claims having no kinship with C aucasian. Our speculations on the origin of the T aiwanese/ C hinese B *44:55 will be presented.