HLA class II genes poIymorphism in DR4 giant cell arteritis patients

We have previously reported a significant increase of HLA-DR4 antigen frequency in giant cell arteritis (GCA). This finding suggested an important role of immunogenetic factors in this syndrome. Recent data suggest that inherited susceptibility to several autoimmune diseases was associated with specific DR4 associated DQ β alleles. DNAs from 27 DR4 positive patients with GCA were digested with Taq I and Barn HI, analysed on 0.7% agarose gel and hybridized with DR β, DQ α and DQ β probes. DR β hybridization produced no variant detectable within DR4. DQ β probe confirmed two clusters among DR4 associated DQW3 alleles: DQW 3.1 (Bam HI 360 Kb) and DQw 3.2 (Taq I 1.9 Kb and Bam HI 11 Kb). Among our 27 DR4 positive patients, 34% were DQW 3.1 and 66% were DQW 3.2. These frequencies are the same as those observed in healthy controls.