GENETIC RISK FACTOR FOR ABDOMINAL AORTIC-ANEURYSM - HLA-DR2(15), A JAPANESE STUDY

Purpose: Autoimmunity has been proposed to play a role in the pathogen esis of the abdominal aortic aneurysm (AAA). Several autoimmune diseas es are associated with specific HLA DR alleles. These experiments were carried out to determine whether the same HLA DR types that have been reported to be associated with AAA in a mixed North American populati on are similarly associated with AAA. in a more homogeneous group of p atients in Japan. Method: HLA DR typing was performed by a serologic m ethod on samples of peripheral blood of patients with nonspecific infr arenal AAA in Nagasaki University Hospital in Japan. The frequencies o f HLA DR antigens were compared with those of volunteers approximately matched for age and sex from the same referral area. Results: HLA DR haplotypes were determined in 46 Japanese patients with AAA and in 50 patients in a control group. The HLA-DR2(15) antigen was observed in 2 7 (58.7%) patients (29 alleles 31.5%) with AAA and in 14 (28%) subject s (16 alleles 26.0%) in the control group (p <0.005). Conclusions: The data suggest that HLA-DR2(15) has an important role as a genetic risk factor for AAA in Japanese patients, as previously reported in a mixe d North American population.