MOLECULAR ANALYSIS OF HLA CLASS-II GENES IN PRIMARY SJOGRENS-SYNDROME- A STUDY OF ISRAELI JEWISH AND GREEK NON-JEWISH PATIENTS

In an attempt to define the role of HLA class II genes in predispositi on to primary Sjogren's syndrome, patients of two different ethnic gro ups (Israeli Jews and Greeks of non-jewish origin) suffering from this disorder were studied. Oligonucleotide genotyping revealed the majori ty in both groups to carry either DRB1 1101 or DRBI*1104, alleles tha t are in linkage disequilibrium with DQB10301 and DQA1*0501. The high frequency of the two alleles in these SS patients is in contrast with the accepted association of primary SS with HLA-DR3 in Italian and Am erican individuals. Molecular analysis of DQB1 and DQA1 alleles found in American Caucasian and American black SS (or SLE) patients demonstr ated high frequencies of DQB10201 and DQA1*0501. The fact that the ma jority of SS patients, across racial and ethnic boundaries, carry a co mmon allele, DQA10501, implies its involvement in the predisposition to primary SS. Based on sequence analysis and the computer imaging of the HLA class II molecule structure, a hypothetical model for the role of the DQ molecule in promoting primary SS is proposed.