Abstract
Infection with microorganisms such as Helicobacter pylori and Chlamidia pneumoniae has been associated with coronary heart disease (CAD) and hypertension (HT). Infection increases the release of proโinflammatory cytokines, thus facilitating interactions that lead to vascular damage and other effects. We hypothesized that genetically determined differences in activity or responsiveness of cytokine(s) might contribute to HT. The interleukinโ1 gene (IL1) cluster on chromosome 2q14 contains three related genes (IL1A, IL1B, and IL1RN) located within a 430โkb region. These encode ILโ1ฮฑ and ILโ1ฮฒ, as well as their endogenous receptor antagonist, ILโ1ra. The IL1RN gene has a pentaโallelic 86โbp tandem repeat in intron 2. Allele IL1RN* 2 is associated with a wide range of chronic inflammatory and autoimmune conditions, and its combination with the โโ31T variant of an IL1B C(โโ31)T polymorphism constitutes a proโinflammatory haplotype that leads to vigorous ILโ1ฮฒ production. We therefore tested each of these polymorphisms for association with HT. Subjects were white AngloโCeltic residents of Sydney, Australia. Frequencies of IL1B C(โโ31)T genotypes CC, CT, and TT were 0.50, 0.40, and 0.10 in normotensive (NT) and 0.46, 0.46, and 0.08 in HT, respectively (ฯ^2^โ=โ1.2, Pโ=โ0.55). T allele frequency in NT (0.30) was similar to that in HT (0.31). For the IL1RN variant, frequencies of alleles IL1RN* 1 and * 2 and combined minor alleles * 3, * 4, and * 5 were 0.61, 0.36, and 0.03 in NT and 0.54, 0.36, and 0.10 in HT, respectively (ฯ^2^โ=โ11, Pโ=โ0.004). In conclusion, no association of the IL1B C(โโ31)T with HT was found, whereas combined frequency of the minor alleles of the IL1RN polymorphism was increased in the HT cohort studied. ยฉ 2001 WileyโLiss, Inc.