Comparative analysis of the association of HLA-B*51 suballeles with Behcet's disease in patients of German and Turkish origin

Abstract

The distribution of the different HLA-B*51 suballeles among patients with Behcet's disease (BD) of German (n = 33) and Turkish (n = 92) origin in comparison to their presence in the respective ethnically matched healthy control groups (German: n=325, Turkish: n=93) was studied. HLA-B*51x was significantly increased in both patient groups in comparison to the controls (Germans: 58% vs. 12%, OR 9.76, P <0.001; Turkish: 75% vs. 25%, OR 9.13, P <0.001), Molecular subtyping of B*51x revealed HLA-B*51011 and B*5108 as the predominant suballeles in both patient groups and controls although with a slightly increased frequency of HLA-B*5108 in the diseased individuals. HLA-B*5105 was the only further HLA-B*51x subtype detected in one Turkish patient heterozygous also for HLA-B*5101. HLA-B*5107 although present in a Turkish as well as German control was absent in the patient groups. There was also a tendency towards a higher degree of homozygosity for HLA-B*51x in both patient groups versus the matched controls (Germans: 10% in patients vs. 2,5%. in controls; Turkish: 27% in patients vs. 13" in controls), Our study further supports previous hypothesis of an association of BD with B51 suballeles which share aminoacid residues at positions 63 and 67 as well as at positions 77-83 for specific peptide binding and natural killer (NK)-cell interactions. This applies to HLA-B*5101 and B*5108, but not to HLA-B*5107 different at position 67, which could be negatively associated with BD.