Allele typing of HLA-A10 group by nested-PCR-low ionic strength single stranded conformation polymorphism and a novel A26 allele (A26KY, A*2605).

HLA-A26 is one of the most polymorphic HLA-A locus antigens among the Japanese population. Four HLA-A26 subtypes have so far been defined: A*2601-2604 [1]. We developed a means of typing alleles of the HLA-A10 group by nested PCR low ionic strength single-stranded conformation polymorphism (NPCR-LIS-SSCP) that is simple and cost effective. We used it to type 200 DNA samples from unrelated Japanese individuals who were serologically HLA-A26 positive. We found a novel A26 allele that had been suggested by PCR-SSO. Sequence analysis of A26KY (officially assigned A*2605, Accession No. D50068) revealed that the allele differs from A*2601 by a single nucleotide substitution at position 299, which leads to an amino acid substitution Ala-->Glu at position 76 in the alpha helix loop of the alpha 1 domain. From our results, A*2605 is likely to originate from A*2601 by a single point mutation. HLA-A*2601 showed the highest frequency (61.9%), followed by A*2603 (19.5%), A*2602 (17.6%), A*2604 (0.5%), and A*2605 (0.5%) in Japanese.