Association of Interleukin-1 Gene cluster polymorphisms with coronary slow flow phenomenon

Coronary slow flow phenomenon (CSFP) is characterized by the decreased rate of contrast progression in epicardial coronary arteries in the absence of significant coronary stenosis. Mounting evidence has showed a significant association between inflammation and CSFP severity. This study aimed to evaluate possible associations between interleukin-1 receptor antagonist (IL-1ra) gene variable number tandem repeat (VNTR), IL-1ß -511 single nucleotide (SNP), and IL-1ß+3954 SNP mutations with CSFP.

Forty-eight patients with CSFP and 62 controls with angiographically normal coronary arteries were prospectively enrolled in the study. Genotypes were assessed using the polymerase chain reaction (PCR)-based restriction fragment length polymorphism (PCR-RFLP) technique.

Homozygote genotype for allele 2 of+3954 C>T 2/2 genotype was significantly more frequent in patients with CSFP than in the control group, whereas 1/2 genotype was more frequent in the control group (35.4% versus 14.5% for 2/2 genotype and 25% versus 35.5% for 1/2 genotype in CSFP and control groups, respectively, X²=6.6; p=0.04). The allelic frequency of allele 2 of this polymorphism was significantly higher in the CSFP group than in the control group (47.9% versus 28.6% in the control group, X²=5.6; p=0.02). However, there was no significant difference with regard to genotype or allelic frequencies of IL-1ra VNTR or IL-1ß -511 SNP polymorphisms between patients with CSFP and controls.

IL-1ß+3954 SNP mutations are significantly more common in patients with CSFP. It may suggest that the tendency for inflammation may contribute to the presence of this phenomenon.