Immune Response in Human Longevity

Role of IL-6 and Other Interleukin Genes in Human Longevity 

Systemic inflammation, represented in large part by the production of proinflammatory cytokines, is the response of humans to the assault of the nonself on the organism. 

However, apart from disease states, there is a natural evolution of cytokine production with aging, including decreased T cell proinflammatory IL-2 and interferon-7 (type II pro-inflammatory IFN-7), decreased non-T cell antiinflammatory type I IFN (IFN-a and IFN-/3), and increased non-T cell proinflammatory IL-1, IL-6, and tumor necrosis factor a (TNF-o) [90], The IL-6 is one of the pathogenic elements of inflammatory and age-related diseases (AD and atherosclerosis) and has been defined as the cytokine for gerontologists [91]. 

Explanation for the conflicting findings could be linked to variability in the strength of association between the IL-6-174 G/C promoter polymorphism and longevity, which could be modified by European regional differences in allele frequencies, as seen above [20, 21, 23, 33], In fact, interestingly, the IL-6 C allele frequency appears to vary across Europe, with an increasing trend from south to north in the very old populations. 

Beyond the supposed role of the IL-6, some other cytokine genes, such as IL-10, IL-2, IL-1, and IFN-7 show polymorphisms that may be relevant in 

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