IL gene family

Genes in the IL family provide instructions for making proteins called interleukins and interleukin receptors. Interleukins are a subset of a larger group of proteins called cytokines, which are produced by many types of cells. Cytokines are small proteins that are involved in cell-to-cell communication. They have a wide variety of functions, including roles in immunity, inflammation, and the formation of blood cells (hematopoiesis).

Interleukins are produced by several types of cells, particularly immune system cells called T-lymphocytes and B-lymphocytes. Among their many functions, interleukins promote the growth of immune system cells and help regulate the immune system.

Interleukins exert their effects by interacting with interleukin receptors, which are embedded in the outer membranes of many types of cells. When an interleukin attaches (binds) to its receptor, it triggers a series of chemical signals within the cell that regulate various cell functions.

Researchers have identified at least 33 different interleukins in humans. Most interleukins are named with "IL" followed by one or more numbers and letters (for example, IL1A). Interleukin receptors have similar names, although they also include an "R" to indicate that they are receptor proteins (such as IL23R).

Interleukins and their receptors have been associated with many diseases related to immune system function. For example, several of these proteins have been found to influence the risk of disorders characterized by chronic inflammation, including inflammatory bowel disease, rheumatoid arthritis, a skin disease called psoriasis, and a joint disorder called ankylosing spondylitis. Changes in interleukins and their receptors have also been associated with autoimmunity, an abnormal immune reaction that occurs when the body attacks its own tissues and organs by mistake. Autoimmunity results in inflammation and can damage otherwise healthy cells and tissues.

Researchers are studying interleukins as a potential treatment for cancer. This form of treatment is designed to stimulate the growth of immune system cells that can destroy cancer cells. The U.S. Food and Drug Administration (FDA) has approved the use of one interleukin, called interleukin-2 or aldesleukin, for the treatment of metastatic kidney cancer and metastatic melanoma (an aggressive form of skin cancer). Interleukins are also under study as possible treatments for other forms of cancer.