Recombination of HLA haplotypes in Guangdong Han nationality

OBJECTIVE: To analyze the human leukocyte antigen complex class I (-A, -B & -C) and class II (-DRB1 & -DQB1) linked haplotypes of Guangdong Han nationality and to study the recombination events of five classical loci in the inheritance of HLA haplotypes. METHODS: A total of 939 peripheral blood samples were collected from 198 families in Guangdong Han nationality who came to our center for HLA typing from 2000 August to 2009 December. HLA-(A, B & DRB1) and HLA-(C & DQB1) alleles were typed by low-resolution polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSO) and PCR-sequence specific primers (PCR-SSP) methods respectively. Then the recombination sites were analyzed by familial study. The samples of 52 individuals from the families with exchange recombination were analyzed by the sequence-based typing (SBT) to judge whether the recombination was interallelic or interlocus exchange. RESULTS: Among 543 offspring individuals of 198 families in Guangdong Han nationality, 9 individuals with HLA-A-C-B-DRB1-DQB1 linked haplotypes had a recombination rate of 1.657%. Among 9 HLA haplotypes recombined families, 3 of them were found to have a crossover between HLA-A and -Cw loci and 6 of them a crossover between HLA-B and -DRB1 loci. Four of these recombination events occurred in the most common haplotypes A*3303-Cw*0302-B*5801-DRB1*0301-DQB1*0201 of Guangdong Han nationality. Among 9 cases of recombination, 5 of them were formed by a crossover between maternal chromosomes and 4 cases a crossover between paternal chromosomes. Three individuals with an exchange between A/Cw loci were all females. Among 6 cases with an exchange between B/DRB1 loci, 5 of them were males and 1 case was female. CONCLUSION: During the inheritance, recombination of HLA linked haplotype mainly occurred between A/Cw loci and B/DRB1 loci, the recombination is related to the haplotype-specificity and sex-specificity.