Differences in allele distributions of the cytotoxic T lymphocyte antigen‐4 (CTLA‐4) +49 A/G polymorphism in abdominal aortic aneurysm (AAA) disease versus a control population free of inflammatory conditions

Aneurysms are associated with inflammation and lower plasma levels of CTLA‐4, an inhibitor of T cell activation. The objective of this study was to compare functional pro‐ and anti‐inflammatory gene polymorphisms in AAA versus age‐, gender‐ and ethnically‐matched controls. Polymerase chain reaction (PCR) was done on DNA from 79 AAA and 71 controls. The pro‐inflammatory gene single nucleotide polymorphisms (SNPs) included interleukin‐1 beta restriction fragment length polymorphism (RFLP) in exon 5, and ‐308 tumor necrosis factor alpha RFLP. The anti‐inflammatory SNPs included −318 CTLA‐4 RFLP, +49 CTLA‐4 RFLP, and interleukin‐1 receptor antagonist variable nucleotide tandem repeat (VNTR) in intron 2. The +49 CTLA‐4 A/G SNP allele distributions differed significantly (p<0.01), while the remaining SNPs did not. Interestingly, the healthy controls violated Hardy‐Weinberg equilibrium. This indicated a likely bias in our controls, possibly due to the exclusion of subjects with inflammatory diseases. In conclusion, our data identify an association of the +49 CTLA‐4 A/G genotype and possible protection against inflammatory diseases in a male Caucasian population.