A study by Bonafe` et al. (2001) focused on the role of IL-6 2174 G/C promoter polymorphism in centenarians. Furthermore, two other studies were conducted on this polymorphism in octogenarian and nonagenarian subjects (Wang et al., 2001; Rea et al., 2003). In fact, Wang et al. found no association between human longevity and gene variants of IL-1 cluster, IL-6 2174 G/C promoter, IL10, and tumor nervous factor a, alone or in combination, although there was a reduction of 2.5% of the Il-6*G/*G frequency between nonagenarians and widely age-selected younger control group. On the contrary, Rea et al. found a trend for a reduced frequency of the IL-6*G/*G genotype in 193 octogenarians.

In the present study, we did not find any statistically significant differences in rates between IL-6 2174 G/C alleles and centenarians among the APOE strata, given evidence of an involvement of this polymorphism in longevity (Panza et al., 2004). In fact, we recently showed that the frequency of the APOE 1 4 allele was significantly higher in middle-aged subjects than in centenarians, suggesting selection against 1 4 alleles. In the same study, the 1 2 allele was found to be increased in centenarians although not significantly (Panza et al., 1999). We also observed and reported for the first time a significant geographic trend for increasing 1 2 allele and decreasing 1 4 allele prevalence in centenarian populations from Northern to Southern regions of Europe (Panza et al., 1999). We suggest that this geographical trend could influence the strength of association between the 1 2 allele and longevity, which was recently confirmed in Finnish centenarians (Frisoni et al., 2001).

References:
Bonafe`, M., Olivieri, F., Cavallone, L., Giovagnetti, S., Mayegiani, F., Cardelli, M., Pieri, C., Marra, M., Antonicelli, R., Lisa, R., Rizzo, M.R., Paolisso, G., Monti, D., & Franceschi, C. (2001). A genetic predisposition to produce high levels of IL-6 is detrimental for longevity. European Journal of Immunology, 31(10), 2908-2911.

Frisoni, G.B., Rozzini, R., Pascual, B., Bianchetti, A., Marksteiner, J., Trabucchi, M., & Hock, C. (2001). Interleukin-6 gene polymorphism and plasma levels in Alzheimer’s disease and cognitively healthy individuals. Neurobiology of Aging, 22(4), 613-614.