HLA class II profile and distribution of HLA-DRB1 and HLA-DQB1 alleles and haplotypes among Lebanese and Bahraini Arabs.

The gene frequencies of HLA class II alleles were studied in 95 healthy Lebanese Arab and 72 healthy Bahraini Arab subjects. Our aim was to establish the genetic relationship between Bahraini and Lebanese Arabs in terms of HLA class II gene and haplotype frequencies and to compare these results with frequencies for other countries with populations of Caucasian and non-Caucasian descent. Subjects were unrelated and of both sexes, and HLA-DRB1 and -DQB1 genotyping was done by the PCR sequence-specific primer technique. Comparative analysis of the HLA-DR and -DQ alleles revealed differences in the allelic distribution among Bahraini and Lebanese subjects. Analysis of the 25 HLA-DRB1 alleles that have been investigated showed that the DRB1040101 and DRB1110101 alleles were more frequent among Lebanese, whereas DRB1030101 and DRB1160101 alleles were more frequent among Bahrainis. Similarly, of the seven HLA-DQB1 alleles analyzed, the presence of DQB10201 was more frequent among Bahrainis, whereas DQB1030101 was more frequent among Lebanese. The DRB1160101-DQB1050101 (0.1318 versus 0.0379%) and DRB1030101-DQB10201 (0.1202 versus 0.0321%) haplotypes were more frequent among Bahrainis, while the DRB1110101-DQB1030101 (0.3142 versus 0.1198%) and DRB1040101-DQB10302 (0.1416 versus 0.0278%) haplotypes were more frequent in Lebanese subjects. Furthermore, a high prevalence of the DRB1040101-DRB1110101-DQB10302-DQB1030101 (12.63 versus 1.35%, P = 0.015) and the homozygous DRB1110101-DRB1110101-DQB1030101-DQB1030101 (7.37 versus 0.00%, P = 0.046) genotypes was seen among Lebanese, and DRB1070101-DRB1160101-DQB10201-DQB1050101 (6.76 versus 0.00%, P = 0.034) was seen more frequently among Bahraini subjects. Our results underline significant differences between these two populations in HLA class II distribution, provide basic information for further studies of major histocompatibility complex heterogeneity among Arabic-speaking countries, and serve as a reference for further anthropological studies.