It induces chemotaxis in target cells, primarily neutrophils but also other granulocytes, causing them to migrate toward the site of infection.

In target cells, IL-8 induces a series of physiological responses required for migration and phagocytosis, such as increases in intracellular Ca2+, exocytosis (e.g. histamine release), and the respiratory burst.

The genes encoding this and the other ten members of the CXC chemokine family form a cluster in a region mapped to chromosome 4q.

[12] This process allows the build up of proteolytic enzymes and reactive oxygen species (ROS) which are necessary to break down the ECM and basement membrane.

[13] IL-8 is the primary cytokine involved in the recruitment of neutrophils to the site of damage or infection; in a process called chemotaxis.

Once the neutrophil is rolling along the endothelium, it will come into contact with a IL-8 molecule expressed on the surface which stimulates the cell signalling pathway, mediated through a G-coupled-protein-receptor.

The chemoattractant activity of IL-8 in similar concentrations to vertebrates was proven in Tetrahymena pyriformis, which suggests a phylogenetically well-conserved structure and function for this chemokine.

[19] IL-8 has also been implied to have a role in colorectal cancer by acting as an autocrine growth factor for colon carcinoma cell lines[20] or the promotion of division and possible migration by cleaving metalloproteinase molecules.

[21] It has also been shown that IL-8 plays an important role in chemoresistance of malignant pleural mesothelioma by inducing expression of transmembrane transporters.

[23] High levels of Interleukin 8 have been shown to reduce the likelihood of positive responses to antipsychotic medication in schizophrenia.

In a 2013 study, diazepam, 4′-chlorodiazepam and flunitrazepam markedly reduced NECA-induced interleukin-8 production in that order of potency, whereas clonazepam showed only a modest inhibition.

[26] An increase in IL-8 levels has also been observed in relation to bronchiolitis, a common respiratory tract disease caused by viral infection.