Objectives: Human leucocyte antigens (HLAs) are polymorphic molecules involved in antigen presentation. Associations between HLA type and autoimmune diseases, such as type 1 diabetes and rheumatoid arthritis, are well established but the potential association of genetic variation affecting antigen presentation with cardiovascular disease has not been systematically investigated in large cohorts. The importance of such studies is stressed by recent experimental findings of an involvement of autoimmunity in the atherosclerotic disease process.
Results: An SSP-PCR method was used for HLA genotyping to determine associations of HLA-DRB1, -DQA1 and -DQB1 with cardiovascular disease in a population-based cohort of 1188 acute myocardial infarction (AMI) patients and 1191 matched healthy controls. The HLA-DRB1*0101 allele, as well as the HLA-DRB1*0101-DQA1*01-DQB1*05 haplotype, was found to be associated with increased risk for AMI (OR 1.24; 95% CI 1.00-1.54 for both). In contrast, the DRB1*07 and DQA*02 alleles (OR 0.78; 95% CI 0.65-0.95 for both), as well as the DRB1*07-DQA*02-DQB*02 haplotype, conferred protection (OR 0.79; 95% CI 0.63-0.98). An HLA risk score taking each individual's both haplotypes into account was higher amongst cases (2.43 +/- 0.92 vs. 2.29 +/- 0.95, P = 0.001). The association between HLA risk score and AMI was independent of other cardiovascular risk factors assessed.
Conclusions: This study demonstrates that the associations between HLA-DRB1 and DQA1 loci and cardiovascular disease exists but that they are considerably weaker than those previously reported for other diseases with an established autoimmune aetiology such as type 1 diabetes, systemic lupus erythematosus and rheumatoid arthritis.