Allele and Haplotype Frequencies of Human Leukocyte Antigen-A, -B, and -DR Loci in Koreans: DNA Typing of 1,500 Cord Blood Units / 대한진단검사의학회지

BACKGROUND: The HLA system is known to be the most polymorphic genetic system in human, and HLA allele and haplotype distribution varies widely among different ethnic groups. This study was performed to examine the frequencies of HLA alleles and haplotypes in Koreans. METHODS: We examined HLA-A, -B, and -DR alleles at the serologic level in 1,500 cord blood units obtained from Koreans using the PCR-sequence specific oligonucleotide (SSO) method. Allele and haplotype frequencies were estimated by the maximum likelihood method using the computer program developed for the 11th International Histocompatibility Workshop. RESULTS: HLA alleles found in Koreans were 12 in A, 31 in B, and 13 in DR loci. Most frequent alleles with frequencies > or =10% in each locus in decreasing order of frequency were: A2, A24, A33, A11; B62; DR4, DR15, DR9, and DR13. Two-locus haplotypes with frequencies > or =0.1% were 104 A-B and 115 B-DR haplotypes, among which those with frequencies > or =1.0% showing significant positive linkage disequilibrium (P or =0.1% were identified. The results were similar to those of a previous study in 1,600 Koreans, although some differences were noted in the distribution of some less frequent alleles or haplotypes with frequencies < or =0.5%. CONCLUSIONS: We provided the allele and haplotype frequencies of HLA-A, -B, and -DR in cord blood units of Korean ethnicity defined by a DNA typing method, which can be used as basic data on Koreans for organ transplantation and disease association studies.

The studies of HLA class II (HLA-DR) system by PCR-SSO typing and the relationship with serological method.

By using two methods together, namely, the conventional serological typing and the new method which is oligonucleotide typing, in order to study the HLA system, it was concluded that the new method was better. Some subtypes were detectable from the new method, whereas, the serological typing yielded negative results such as DRB1 subtype "0103". This method, therefore, provided more information in order to study the HLA system. However, the new method was twice as expensive as the conventional serological method.

Reverse-SSO hybridization provides an accurate and simple HLA-DR typing: a comparative study with HLA-DR serologic typing

The HLA-DR molecule is a polymorphic membrane glycoprotein and one of the key molecules causing allograft rejection and graft-versus-host disease in organ transplantation. Serologic typing using DR specific alloantisera has long been used, but several problems have limited its application. The purpose of this study was to establish an efficient reverse-SSO typing system that detects DRB1 and DRB3/B4/B5 alleles on a single membrane. A DR typing membrane was prepared by immobilizing 21 dT-tailed sequence specific oligonucleotides (SSOs) on a nylon membrane and was used in a hybridization assay with digoxigenin-labeled PCR-amplified target DNA. The positive signals were detected on X-ray film using chemiluminescence. A comparison study with serology using DNAs from 105 unrelated individuals demonstrated that the reverse-SSO typing system was superior to serologic typing in terms of accuracy (100% vs 90.5%), simplicity, range of application, rapidity, and cost of the test. These data indicate that the reverse-SSO typing system can replace serology as a routine DR test, and will be useful in time-restricted solid organ transplantation and in selection of an unrelated marrow donor prior to bone marrow transplantation.