Interleukin 8 (IL-8)
Interleukin 8 (IL-8) is also known as granulocyte chemotactic protein 1. IL-8 is a pleiotropic proinflammatory chemokine that plays a key role in the recruitment of neutrophils and other immune cells to the site of infection. As such, many studies use levels of IL-8 as an early-phase biomarker. In addition to being released by macrophages, IL-8 is also released by epithelial cells, airway smooth muscle cells, and endothelial cells. Levels of IL-8 have also been found to be elevated in the cerebrospinal fluid of patients with traumatic brain injury. This analyte is eligible for multiplexing.
Name: Interleukin 8 (IL-8)
Category: Health & Inflammation
Type of test: Blood + Saliva
IL-8, also known as granulocyte chemotactic protein 1, is a chemokine important in mediating the inflammatory response, but also plays a role in other immunological responses, such as chemotaxis of neutrophils and angiogenesis. IL-8 is involved in pathologies such as cancer, Crohn’s disease, and psoriasis, with research indicating that higher levels of IL-8 are linked to disease progression and poorer prognoses. The presence of tumor-derived IL-8 increases localized presence of both myeloid derived tumor cells as well as neutrophils, creating an environment where tumors can evade the host immune system. Further, IL-8 promotes that production of new blood vessels which is critical for the vascularization of cancerous tumors.
One of the most well-established roles for IL-8 in immune responses is its ability to activate the movement of cells, primarily neutrophils, First, it is responsible for increasing expression of adhesion factors that allow for the neutrophil to stick to adjacent tissues, and it then it aids in allowing the neutrophil to pass through the extracellular environment to access target tissues. Accompanying this response is IL-8-induced release of histamines from numerous cell types, which promotes localized vasodilation. The result of this process is neutrophil recruitment to sites of damage or infection.
Within skeletal muscle, IL-8 has been shown to be expressed during periods of eccentric contraction, a relationship that has been proposed to aid in the development of new blood vessels through its angiogenic effects. IL-8 has been investigated clinically as a target to modulate localized inflammation, as well as being analyzed in the context of neurological disorders such as schizophrenia. Interestingly, high IL-8 levels during pregnancy increase the likelihood of a child developing schizophrenia and correlate to an increased likelihood of schizophrenia being resistant to antipsychotic treatment. Some evidence also links IL-8 with obesity, but it is unclear whether this relationship is the result of IL-8 being obesogenic or whether it is a byproduct of obesity itself being linked to systemic inflammation. Ultimately, IL-8 is an important modulator of several biologically relevant processes, and its dysregulation in numerous disease states makes it a promising candidate for future research. IL-12p70 can be measured in both saliva and serum / plasma, but the extent to which levels in these sample types correlate is variable.
David, J. M., Dominguez, C., Hamilton, D. H., & Palena, C. (2016). The IL-8/IL-8R Axis: A Double Agent in Tumor Immune Resistance. Vaccines, 4, e22. doi:10.3390/vaccines4030022 (link)
Gonzalez-Aparicio, M., & Alfaro, C. (2019). Influence of interleukin-8 and neutrophil extracellular trap (NET) formation in the tumor microenvironment: is there a pathogenic role? Journal of Immunology Research, 7, e6252138. https://www.hindawi.com/journals/jir/2019/6252138/
Kim, C. S., Park, H. S., Kawada, T., Kim, J. H., Lim, D., Hubbard, N. E., ... & Yu, R. (2006). Circulating levels of MCP-1 and IL-8 are elevated in human obese subjects and associated with obesity-related parameters. International Journal of Obesity, 30, 1347-1355. https://pubmed.ncbi.nlm.nih.gov/16534530/
Li, A., Dubey, S., Varney, M. L., Dave, B. J., & Singh, R. K. (2003). IL-8 directly enhanced endothelial cell survival, proliferation, and matrix metalloproteinases production and regulated angiogenesis. The Journal of Immunology, 170, 3369-3376. https://europepmc.org/article/med/12626597