HLA-DRB1, DQA1, and DQB1 alleles associated with giant cell arteritis in northern Italy

Objective. To evaluate by molecular typing the possible associations of HLA -DRB1, DQA1, and DQB1 alleles with biopsy proven giant cell arteritis (GCA) in a Mediterranean country, and to examine possible relationships between these alleles and GCA clinical subsets. Methods. Thirty-nine patients from the Reggio Emilia area diagnosed over a 12 year period with biopsy proven GCA were studied. The clinical findings a t diagnosis and during the followup were evaluated through interviews and b y reviewing the medical records. HLA-DRB1, DQA1, and DQB1 alleles were dete rmined in the 39 patients and in 250 healthy controls from the same geograp hic area by polymerase chain reaction amplification using sequence-specific primers. Results. No associations were found between GCA and the shared epitope, the DRYF epitope, or the DRB1*04 or DQA1 alleles. The only significant associa tion was with DQB 1*0302 allele (p = 0.03, RR = 2.2). However, the associat ion was weak and the significance was lost when corrected for the number of antigens tested. The frequencies of DQB 1*0301 and 0302 in DR4 patients we re not significantly different from those observed in DR4 positive controls . Significant associations were found between DRB1*04 allele and the presen ce of systemic signs and/or symptoms (p = 0.04, RR = 1.5) and between DRB1* 07 allele and the male patients (p = 0.04, RR = 2.6). Conclusion. Our data showed no associations of biopsy proven GCA with HLA-D RB1*04 and HLA-DRB1*01 alleles, rheumatoid epitope, or DRYF epitope. Discre pancies with other studies may be related to the different ethnic backgroun ds of the populations studied and to differences in the referral patterns o f patients with GCA.