Interleukin-16 network in inflammation and allergy.

Interleukin (IL)-16 is a homotetramer of 14-kDa subunits discovered in 1982 as a T-cell-specific chemoattractant factor. IL-16 plays a role in trafficking of several immune cells and may be a major chemotactic signal for CD4+ cells. Here, we review some of the key biological actions of IL-16. Because this cytokine has been shown to affect the levels of many inflammatory mediators such as histamine, serotonin, regulated upon activation, normal T cell expressed and secreted (RANTES), and monocyte chemotactic protein-1 (MCP-1), and other cytokines such as IL-2, we investigated the effect of IL-16 on control and stimulated human umbilical cord blood-derived cultured mast cells after antigen challenge. We found that human recombinant IL-16 (0.2-200 ng/mL) does not affect either basal tryptase or IL-8 release or that induced by anti-immunoglobulin E activation. In accordance with other data in the medical literature, we conclude that the most important function of IL-16 is the chemoattraction of CD4+ cells.