HLA-DR2 haplotypic diversity in populations of South-East Asia, northern China, Melanesia and Australian aborigines using PCR-RFLP for DRB1, DRB5, DQA1 and DQB1. A novel DRB1 allele: DRB1*16022.

The polymorphism of the human leucocyte antigen HLA-DR2 and the heterogeneity of HLA-DR2 class II-related haplotypes (HLA-DRB1-DRB5-DQA1-DQB1) were investigated in four populations of east and south-east Asia (SEA) and five Melanesian populations using TaqI restriction fragment length polymorphism (RFLP) analysis, and the polymerase chain reaction (PCR) amplification-based techniques PCR-RFLP and sequence-specific oligonucleotide (SSO) typing. The haplotype DRB11502-DRB50101-DQA10102-DQB10601 was common in Malaysians, Javanese, Thursday Islanders, Madang, Goroka and the Australian Aborigines, while DRB116021-DRB50101-DQA10102-DQB10502 was common in the Thai and Thursday Islanders. DRB11501-DRB50101-DQA10102-DQB10602 was present at a high frequency in Northern Chinese, Goroka, Watut and Australian Aborigines. The study describes four rare or unusual haplotypes: HLA-DRB11501-DRB50101-DQA10101-DQB10601, DRB11502-DRB50101-DQA10101-DQB10502, DRB11502-DRB50102-DQA1* 0102-DQB10502 and DRB11501-DRB50101-DQA10101/2-DQB10503; the latter two were confirmed by segregation in two Javanese families. A new DR2 allele, initially detected by PCR-RFLP and confirmed by DNA sequencing as DRB116022 (previously designated DRB116Madang), was seen in a Madang individual. A new HLA-DR2 TaqI RFLP subtype, locally designated as DR15U, is also described. This RFLP subtype segregated in a Javanese family and correlated with a typically SEA haplotype, DRB11502-DRB50102-DQA10101-DQB10501. The allele HLA-DR16Thai, determined by TaqI DRB RFLP, was found by PCR-RFLP and SSO typing to correlate with a unique SEA haplotype, HLA-DRB116021-DRB50101-DQA10102-DQB1*0502, and was observed in the Thai, Malaysian, Thursday Islander, Javanese and Northern Chinese populations.