A new B18 Sequence (B ∗1802) from Asian individuals

Abstract

A new HLA-B18 allele (B ∗1802) derived from a Thai individual was sequenced. Comparison of this B18 nucleotide sequence with the published B ∗1801 sequence indicated that this Asian B18 allele has a nucleotide sequence different from that of B ∗ 1801. Three nucleotide changes were observed in exon 3, in which two substitutions at codon 97, AGG in B ∗1801 to AAT in the B ∗ 1802, result in an amino acid change from arginine to asparagine. The residue 97Asn has also been described in some B27 subtypes. A silent mutation was also observed at codon 99, TAC in B ∗1801 to TAT in the B ∗1802. This sequence has been reported in many class I alleles published so far. Moreover, 18 HLA-B18-positive samples were examined by the PCR-SSO method using specific probes for B ∗1801 and B ∗ 1802. The results demonstrated that three Asian samples possess B ∗1802 and share HLA-Cw7, DR 12, and DQ7