Inflammation is a protective response to infection by the immune system that requires communication between different classes of immune cells to coordinate their actions. Acute inflammation is an important part of the immune response, but chronic inflammation can lead to the destruction of tissues, for example in autoimmune disorders. Secreted cytokine proteins provide the necessary signals between immune cells to coordinate the inflammatory response.
A key family of cytokines is IL-1. This group of 11 cytokines induces a complex network of pro- and anti-inflammatory cytokines to regulate leukocytes and endothelial cells throughout the induction and resolution of inflammatory responses.
IL-1 has a great deal of clinical significance. The blockade of IL-1 activity is a popular therapy for autoimmune diseases or lymphomas. For example, IL-1 is used as a therapy for patients with rheumatoid arthritis, because it reduces symptoms and slows joint degradation. It has also been prescribed to patients with indolent or smoldering myeloma that have a high risk of progression to multiple myeloma.
Produced by activated macrophages, IL-1 stimulates thymocyte proliferation by inducing IL-2 release, B-cell maturation / proliferation, and fibroblast growth factor activity. IL-1 proteins are involved in the inflammatory response, being identified as endogenous pyrogens, and are reported to stimulate the release of prostaglandin and collagenase from synovial cells.
MCP-1 is a chemotactic factor that attracts monocytes and basophils but not neutrophils or eosinophils. It also augments monocyte anti-tumor activity. MCP-1 has been implicated in the pathogenesis of diseases characterized by monocytic infiltrates – such as psoriasis, rheumatoid arthritis and atherosclerosis- where it has been associated with the recruitment of monocytes into the arterial wall during the disease process of atherosclerosis.