Identification of the novel allele HLA-DRB1*1137 which probably originated from DRB1*11011: implications for mismatch with its ancestor allele at bone marrow transplantation.

The identification of the new allele HLA-DRB1*1137, which was found in a Caucasian individual, is described. In the sequence analysis the new allele differs from DRB1*11011 by position 227 (T>A) which is located in exon 2. At the protein level, the new allele has one amino acid difference compared to DRB1*1101 (Phe47Tyr). Residue 47 is likely to contribute to the peptide binding site of HLA-DR11 and thus to be important for peptide binding. However, as phenylalanine and tyrosine have very similar physical and chemical features allogenicity in case of mismatch at bone marrow transplantation may be weak.