Identification and efficient genotyping of an (A)n/(T)m polymorphism within the 5' untranslated region of the human IL6 gene

Modest implication of interleukin-6 promoter polymorphisms in longevity

The multifunctional interleukin-6 has been suggested to contribute to a chronic low-grade inflammatory status, thereby conferring susceptibility to age-related pathological conditions as well as functional decline and increased mortality. Several polymorphisms have been identified in the interleukin-6 promoter, but investigation of the effect of these on interleukin-6 levels and disease susceptibility have led to contradictory results. This study investigates the significance of the three single-point polymorphisms (-597G/A, -572G/C and -174G/C) and the AT-stretch polymorphism (-373(A)n(T)m) in ageing, by comparison of the frequency of each single polymorphism separately as well as the entire promoter haplotype in a total of 1710 Danish subjects ranging in age from 47 to 100 years. We found a modest, but significant, increase in the frequency of interleukin-6 -174GG homozygotes with age suggesting that this genotype is advantageous for longevity.

Interleukin-6 (IL-6) − 373 A9T11 allele is associated with reduced susceptibility to chronic periodontitis in Japanese subjects and decreased serum IL-6 level

We investigated whether interleukin-6 (IL-6) gene polymorphisms could be associated with chronic periodontitis (CP) and serum IL-6 level. One hundred and twelve CP and 77 non-CP Japanese subjects were analyzed for IL-6 -597 (G/A), -572 (C/G), -373 (A(n)T(m)), -190 (C/T), and -174 (G/C) polymorphisms. We could only detect -572 and -373 polymorphisms and found that the frequency and carriage rate of the -373 A9T11 allele were significantly higher in non-CP subjects. Enzyme-linked immunosorbent assay confirmed that the -572 and -373 G[A9T11] haplotypes were associated with lower serum IL-6 level. These findings suggest that IL-6 -373 A9T11 allele could be associated with reduced susceptibility to CP among Japanese subjects and decreased serum IL-6 level.