HLA class II allele frequencies in the Lebanese population.

Human leukocyte antigens (HLA) allele determination is becoming an increasingly important aspect in the field of transplantation as well as in the area of HLA association with a number of diseases. Through Lebanon's history, this country, situated at a crossroads between Europe, Asia and Africa, has been a host for various populations of different ethnicities. The aim of our study is to determine whether allele polymorphisms in the Lebanese population present a distinguishing feature. Although data on HLA phenotypic polymorphisms in Lebanon have been reported in the literature, our study is the first to examine frequencies of HLA polymorphisms in the country at the molecular level. Allele frequencies of the Lebanese population were analyzed and compared with those of other populations. HLA class II genotyping of DRB1* and DQB1* loci by PCR-sequence-specific primer (SSP) was performed on 191 unrelated Lebanese subjects of both sexes and of different regions and sects in Lebanon. The study revealed that DRB1*1101, DRB1*0401 and DRB1*0301 were the three most common DRB1* alleles observed (respective allele frequencies of 0.302, 0.164 and 0.096). In the DQB locus allele group, DQB1*0301 (allele frequency of 0.384) was highly predominant followed by the DQB1* 0501, DQB1*0201 and DQB1*0302 with respective allele frequencies of 0.199, 0.195 and 0.103. These results confirm previous serological studies and show the high prevalence of DRB1*1101 and DQB1*0301 in Lebanon, which could be explained by the high frequency of consanguineous marriages in the population. The presence of other common alleles is consistent with historical data showing that the Lebanese population is an admixture of various ethnicities.