IL6

Interleukin-6 (IL-6) is a cytokine, a type of molecule released by cells to signal to other nearby cells or tissues, with an important role in the immune system and is encoded for by the IL6 gene ¹. IL-6 was first described as an inflammatory cytokine, released by cells of the immune system during infection in order to attract other immune cells, to help combat infection. As such its expression is typically short lived ².

However, more recently several other important roles for IL-6 have been described. Under conditions of psychological stress IL-6 release has been shown to increase, and be maintained for long periods of time. Whereas, short lived expression of IL-6 is beneficial when dealing with infection, extended IL-6 expression can actually promote viral infection, and increase the severity of symptoms. It is thought that aberrant IL-6 expression provides the link between chronic-stress, as associated with depression and anxiety and an impaired immune response ³.

In the above two examples IL-6 is playing a role in influencing the immune system. It has also been shown to play an important role in muscle tissue, where it is released in large amounts following exercise ⁴. It was initially thought that this was an immune response to the damage caused to muscle cells by strenuous exercise. However, it was later shown that IL-6 is instead promoting a beneficial effect stimulating the release of glucose from the liver and fat tissue, promoting the breakdown of fat ⁵.

There is one SNP in the IL6 gene associated with poor health outcomes, rs1800795 sometimes called C-237G or C-174G.