HLA CLASS-II GENE POLYMORPHISM IN TUNISIANS

The polymorphism of HLA das II genes (HLA-DRB, DQB, DPB) was investiga ted in 101 Tunisians using polymerase chain reaction (PCR) amplificati on and reverse dot blot (RDB) hybridization. Allele and haplotype freq uencies, as well as DRB1-DQB1 linkage disequilibria, were calculated. A total of 26 DRB1 alleles were detected and the most prevalent varian t was DRB10301 with an allelic frequency at 21.87%. In the DR1 group, DRB10102 was most frequent than DRB1*0101. In the DR4 group, DRB1*04 03 was the most common allele and was associated with DQB1,0402. Inte restingly this DRB1-DQB1 association has not been observed in other po pulations. With regard to the DR8 group, DRB10804 was the unique vari ant detected, whereas with the DR13 specificity, the most common varia nt was DRB11303 in Algerians also. Although the DQB1 polymorphism ana lysis showed an allelic distribution very close to that observed in ca ucasords, many DRB1-DQB1 associations which have not been reported in studies of other populations, were described. Finally at the DPB1 locu s DPB11701 and *1301 allele frequencies distinguish clearly this Tuni sian sample from a French caucasoid panel of 83 subjects. In conclusio n, a specific distribution of HLA components in terms of gene and hapl otype frequencies characterizises this Tunisian population. This speci fic pattern may reflect the great ethnic diversity of this community. All these informations may be helpful in the future for HLA and diseas e association studies.