Purpose: autoimmunity has been proposed as one of the pathogenesis of abdominal aortic aneurysm (AAA). There is also a likelihood that when aorto-iliac occlusive disease (AIOD) coexists with AAA, some other occlusive atherosclerotic diseases, such as ischemic heart disease and cerebrovascular disease, may develop, leading to a very poor long-term prognosis. Previous studies using serological HLA typing showed that HLA-DR15 was a risk factor for AAA. In this study, we performed HLA-DNA typing by PCR to clarify the relationship between AAA and HLA genotypes in Japanese patients with AAA. In addition, we analyzed whether HLA genotypes are involved in the pathogenesis of AIOD.
Results: we examined 78 HLA genotypes of class I (HLA-A and -B) and class II (HLA-DR) and found that 60.4 and 30.4% of 49 AAA patients had HLA-A2 and HLA-B61, respectively. These frequencies were significantly higher than those in control individuals (HLA-A2, p < 0.05; HLA-B61, p < 0.005). We also found that 55.6% of nine AAA patients with AIOD had both HLA-B52 and HLA-DR B1*1502. In contrast, only 10.0% each of 40 AAA patients without AIOD showed HLA-B53 or HLA-DR B1*1502.
Conclusions: this study showed that HLA A-2 and HLA B-61, but not HLA DR-15, were important genetic risk factors for the development of AAA among the Japanese population. We also found high frequencies of HLA-B52 and HLA-DR B1*1502 in the AAA patients with AIOD than in those without, although this must be confirmed using a larger number of AAA patients with AIOD.