HLA-DRB1, DQA1, DQB1 DNA polymorphism in the Bulgarian population.

We describe for the first time the use of PCR based techniques to analyze the MHC class II polymorphism of the Bulgarian population. The present study provides the HLA-DRB, DQB1 allele frequencies in 116 Bulgarian individuals and DQA1 alleles frequencies in 100 subjects. DNA from these individuals was typed for DRB and DQB1 typed by the PCR-Allele Specific Amplification (PCR-ASA) method and DQA1 by PCR followed by hybridization using Sequence Specific Oligonucleotides (PCR-SSO). Allele and haplotype frequencies and linkage disequilibria are computed by the standard methods used for the XIth International Histocompatibility Workshop. The highest frequencies are 0.159, 0.109 and 0.085 for DRB11101, DRB11601 and DRB11301 respectively. Among the eight DQA1 alleles detected, DQA10501 (0.344) is found to be much more frequent than the two most frequent alleles DQA10102 (0.225) and DQA10101 (0.151). Twelve DQB1 alleles are found and three of them, DQB10301 (0.280), DQB10502 (0.153) and DQB10201 (0.133) showed the highest frequencies. The haplotype DRB11101-DQA10501-DQB10301 (0.079) predominate clearly, followed by DRB11601-DQA10102-DDQB10502 (0.055) and DRB10101-DQA10101-DQB10501. These results indicate that the Bulgarian population is characterized by features representative of the European anthropological type with a substantial contribution from the Southern Belt of Europe.