Polymorphism of HLA-B* 40 gene family in Chinese Han population / 中国实验血液学杂志

To investigate the allele distribution of HLA-B* 40 gene family in Chinese Han population and to study its influence on the selection of clinical transplantation donor, the HLA-B genetypes of 381 individuals randomly selected from Chinese National Marrow Donor Project were identified by PCR-SSO, and then all the HLA-B* 40 positive samples from the above population and the B* 40 homozygote samples received from another 1 270 registered donors were analyzed by PCR-SBT and PCR-SSP at high resolution. The results showed that the population of 381 registered donors was examined at HLA-B locus by using Hardy-Weinberg equilibrium, the gene frequency of HLA-B* 40 was 0.1692. Four different HLA-B* 40 alleles (B* 4001, B* 4002, B* 4003, B* 4006) were identified, and the serological specificity was B60 and B61 respectively. The relative frequency of each allele was 0.1192 for B* 4001, 0.0154 for B* 4002, 0.0038 for B* 4003, 0.0308 for B* 4006. The distribution of B* 40 homozygote revealed a certain regularity at high-resolution, B* 40XX (B* 4001 group), at low-resolution; B* 4001 at high resolution; B* 40XX (B* 4002 group), at low-resolution; B* 4002 or B* 4006 or heterozygote of both at high-resolution. It is concluded that in Chinese Han population, predominant allele in HLA-B* 40 gene family is B* 4001, the high-resolution typing may be recommended to use for the selection of clinical transplantation donor.

Diversity of HLA-B*40 Alleles and Haplotypes in Koreans / 대한진단검사의학회지

BACKGROUND: HLA-B40 includes two serologic specificities, B60 and B61, and at least 45 alleles of the B*40 group have been identified. B40 shows a gene frequency of 13.4% (B60 4.5%, B61 8.9%) in Koreans. In this study, the distribution of HLA-B40 alleles and their association with HLA-A, -Cw and -DRB1 alleles were investigated in the Korean population. METHODS: A total of 453 healthy unrelated Koreans including 215 parents from 108 families were studied. For all samples, HLA-A, B, C serological typing, HLA-Cw low resolution typing using polymerase chain reaction (PCR)-sequence specific oligonucleotide (SSO) method, and HLA-DRB1 geno-typing using PCR-single strand conformation polymorphism (SSCP) method were performed. All of the 112 samples (24.7%) typed as B40 by serology were analyzed for B40 alleles using the PCR-SSCP method. RESULTS: Four B40 alleles were detected in the Korean population and their allele frequencies were: B*4001 4.4%, B*4002 5.0%, B*4003 0.4%, and B*4006 3.2%. A significant association (P<0.05) was observed for B*4001 with A24, A11, Cw*03, DRB1*0405, and DRB1*1405; B*4002 with A2, A26, Cw*03, DRB1*0405, DRB1*0802, DRB1*1401, and DRB1*1405; and B*4006 with A2, Cw*08, DRB1*0901, and DRB1*1201. Each B40 allele was very strongly associated with a particular Cw allele: B*4001 -Cw*03, B*4002-Cw*03 and B*4006-Cw*08. However, B40-DRB1 haplotypes showed weaker associations and diversity. CONCLUSIONS: The Korean population shows a heterogeneity in the distribution of B40 alleles and related haplotypes, and thus B40 subtype mismatch can occur between serologically matched donorrecipient pairs in unrelated marrow transplantation.

HLA-B60 and HLA-B61 Discrimination by PCR using Sequence-specific Primers (PCR-SSP) Method / 대한임상병리학회지

BACKGROUND: HLA-B40 is the most frequently identified HLA-B type in Koreans. Also HLA-B60 and B61 are the serologic split antigens of HLA-B40. But because of the lack of mono-specific alloantisera, cross reactivity of sera used as typing reagents, and poor antigenicity of some specific cells such as cord blood lymphocytes, discrimination between HLA-B60 and B61 has been often problematic in laboratories. In this study, authors evaluated whether the PCR-SSP method can be useful for accurate assignments of HLA-B60 and B61 or not. METHODS: Twenty-nine lymphocytes samples which were suspected as heterozygotes or homozygotes of HLA-B60 or B61 and three samples typed as HLA-B40 are selected from stored cord blood and organ transplantation donors. HLA types of these samples were defined by serologic method using a commercial typing kit. PCR that amplified exons 2 and 3 of the HLA-B gene using sequence specific primer pairs exactly matched to HLA-B60 or B61 allele making up a serological specificity was done. RESULTS: A clear discrimination between B60 and B61 was possible in all samples including 9 serologically ambiguous samples. Discrepancy between serologic typing and molecular typing was seen in three cases identified serologically as B40 positive but inable to define a split. Among three samples, two were identified as HLA-B61 and one was identified as HLA-B60. CONCLUSIONS: Molecular typing was useful in discriminating between HLA-B60 and B61. The PCR-SSP method for HLA-B60 and B61 including other cross-reactive HLA types will be helpful as a supplemental method of the serologic typing.