The frequencies of the human leukocyte antigen alleles HLA-A, HLA-B, and HLA-DRB1 and the A-B-DRB1, A-B, and B-DRB1 haplotypes were studied in Naxi and Yunnan Han populations using polymerase chain reaction (PCR)-sequence-specific amplification for alleles A and B and a PCR-microtiter plate hybridization method for the DRB1 allele. A total of 8 A, 19 B, and 30 DRB1 alleles were found in the Naxi population, and 15 A, 21 B, and 36 DRB1 alleles were found in Yunnan Han population. The common A-B-DRB1 haplotypes in the Naxi population were A*24-B*15-DRB1*1202, A*11-B*15-DRB1*0405, A*11-B*15-DRB1*1202, A*11-B*38-DRB1*08032, and A*11-B*55-DRB1*0405; the common A-B haplotypes were A*11-B*15, A*11-B*38, and A*24-B*15; and the common B-DRB1 haplotypes were B*15-DRB1*1202, B*38-DRB1*08032, and B*48-DRB1*1201. In the Yunnan Han population, the common A-B-DRB1 haplotypes were A*24-B*15-DRB1*1501, A*24-B*46-DRB1*08032, and A*24-B*15-DRB1*1201; the common A-B haplotypes were A*24-B*15, A*24-B*46, and A*34-B*46; and the common B-DRB1 haplotypes were B*15-DRB1*1501, B*46-DRB1*09012, and B*46-DRB1*1401. Phylogenetic tree and principal component analyzes based on HLA-A, HLA-B, and DRB1 allele frequencies suggested that the Naxi ethnic group belongs to the southern Chinese groups, while the Yunnan Han population is a characteristic population located intermediate between northern and southern Chinese groups, although they live in the southwest of China.

The genetic polymorphism of the HLA class II loci was investigated in a Manchu population resident in the northern part of China and compared with those of other Asian populations including Japanese and Han. In 8 DQA1 alleles, the most frequent allele was DQA1*03 with the gene frequency of 25.5%. Of 15 DQB1 alleles tested, 11 were observed and the most common allele was DQB1*0301 with the gene frequency of 24.5%. Among 19 DPB1 alleles, 11 were detected and DPB1*0501 (43.8%) was the most frequent allele as observed in other Asian populations such as Japanese, Chinese and Korean. Of 43 DRB1 alleles tested, 21 were detected and DRB1*0901 (14.0%), *1501 (11.0%), *1201 (11.0%), *07 (9.0%) and *1401 (9.0%) were highly predominant and account for the high frequencies of DR9, DR2, DR5, DR7 and DR6. In the DRB3 gene (DR52), DRB3*0202 (18.0%) was the most frequent. With respect to the DRB4 gene (DR53), the gene frequency of DRB4*0101 was 35.0%. Of 3 DRB5 alleles detected, DRB5*0101 (11.0%) was highly predominant. Comparison of HLA class II allele frequencies in Manchu with those in Japanese and Han Chinese populations (South & North) detected some significant differences and genetic divergence between these Oriental populations. The dendrogram constructed by the neighbor-joining (NJ) method based on the allele frequencies of DQA1, DQB1, DPB1 and DRB1 of 10 representative populations over the world suggested that Manchu is the closest, but at the same genetic distance to both Northern and Southern Han Chinese.

High-frequency alleles and/or co-occurring human leukocyte antigen alleles across loci appear to be more important than individual alleles as markers of disease risk and have clinical value as biomarkers for targeted screening or the development of new disease therapies. To better elucidate the major histocompatibility complex (MHC) background and to facilitate the experimental use of cynomolgus macaques, Mafa-DPA1, Mafa-DQA1, Mafa-DRA, and Mafa-DOA alleles were characterized, and their combinations were investigated in 30 Vietnamese macaques by gene cloning and sequencing. A total of 26 Mafa-DPA1, 18 Mafa-DQA1, 9 Mafa-DRA, and 15 Mafa-DOA alleles, including 7 high-frequency alleles, were identified in this study, respectively. In addition, 15 Mafa-DQA1, 17 Mafa-DPA1, 15 Mafa-DOA, and 2 Mafa-DRA alleles represented novel sequences that had not been documented in earlier studies. Our results also showed that the Vietnamese macaques might be valuable because no less than 30% of the test animals possessed Mafa-DRA*01:02:01 (90%), -DQA1*26:01:03 (37%), -DOA*01:02:07 (34%), and -DQA1*01:03:03 (30%). We previously reported that the combinations of MHC class II alleles, including the combination of DOA*01:02:07-DPA1*02:09 and DOA*01:02:07-DQA1*01:03:03, were detected in 17 and 14% of the animals, respectively. Interestingly, more than two Mafa-DQA1 and Mafa-DPA1 alleles were detected in one animal in this study, which suggested that they might be caused by a chromosomal duplication. If our findings can be validated by other studies, it will further enrich the number of known Mafa-DPA1 and Mafa-DQA1 polymorphisms. Our results identified the co-occurring MHC alleles across loci in a cohort of Vietnamese cynomolgus macaques, which emphasized the value of this species as a model for biomedical research.