title: The nature of recombination in HLA-B*4207.
abstract: The identification of the novel human leukocyte antigen (HLA)-B*4207 allele, which was found in a blood donor of Caucasian origin, is described. The sequence of the new allele differs from HLA-B*4201 in three nucleotide substitutions in exon 2, resulting in three consecutive amino acid (AA) exchanges at position 69, 70, and 71. AA positions 69 and 70 affect the peptide-binding site of the HLA molecule in the formation of pockets A, B, and C. Therefore, it is likely that the peptide-binding motif of HLA-B*4207 differs from the HLA-B*4201 motif. HLA-B*4207 exhibits a high level of structural homology to HLA-B*08 alleles as well as to HLA-B*4201. Rating of the AA variations of these alleles according to the AA distance matrix score gives the lowest overall matching score between the HLA-B*4207 and the HLA-B*0801 alleles, indicating a high functional similarity. To further address this, homology modeling was performed using B8 as the closest structural template. The portion of the molecule that is accessible to the T-cell receptor and antibodies is identical between B*4207 and B*0801. Under consideration of allele frequencies, close inspection of these sequences shows that the new allele is most likely a result of a recombination involving B*0702 and B*0801. Unfortunately, patient consent could not be obtained for retrospective serological typing to definitively determine whether B*4207 reacts in the B8 serological group.
authors.affiliation: Institute for Transfusion Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Eiz-Vesper
authors.forename: D S
authors.initials: DS
authors.lastname: Deluca
authors.forename: R
authors.initials: R
authors.lastname: Blasczyk
authors.forename: P A
authors.initials: PA
authors.lastname: Horn
mesh_terms: D000483:Alleles; D015235:HLA-B Antigens / Q000235:genetics*; D006801:Humans; D011995:Recombination, Genetic
chemical_list: D015235:HLA-B Antigens