[Identification and sequence analysis of a novel HLA-A * 3018 allele]

To identify HLA novel allele in Chinese Han individuals, an unknown HLA-A allele was detected by PCR-SSP and FLOW-SSO in Chinese Han individuals. Heterozygous sequence-based typing (SBT) showed that there were 3 differences compared with database in exon 2. Its anomalous patterns suggested the possible presence of either a novel A * 30 or a novel A * 24. To separate the two alleles and to determine whether the allele is novel, the HLA-A * 30 and HLA-A * 24 alleles were amplified separately by using a commercial kit for the single allele-specific sequencing strategy, and both alleles for exons 2 - 4 were sequenced according to the manufacturer' protocol. To prepare B-lymphoblastoid cell line of the novel HLA allele by using Epstein-Barr virus-infected B-lymphoblastoid cells in the peripheral blood. The results indicated that the sequencing results showed HLA-A alleles of the sample to be HLA-A * 240201 and a new A * 30 allele. The sequences of the new A*30 were identical to those of HLA-A * 300101 except for three nucleotide changes in exon 2: at nt 121 (A-->C), nt 123 (T-->C) and nt 126 (A-->G), resulting in an amino acid residue substitution from S (AGT) to R (CGC) at codon 17 and a synonymous substitution from G (GGA) to G (GGG) at codon 18. Immortalized B-lymphoblastoid cell line of the novel HLA-A * 3018 allele was achieved, the sequence of HLA-A * 3018 allele was submitted to GenBank and its accession number was DQ872509. In conclusion, the HLA-A * 3018 is a novel HLA-A allele and has been officially named HLA-A * 3018 by the WHO Nomenclature committee in August 2006 (HWS10004039).