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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

IL gene family

Reviewed February 2011

What are the IL genes?

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.

Which genes are included in the IL gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides an index of gene families ( and their member genes.

Genetics Home Reference summarizes the normal function and health implications of these members of the IL gene family: IL1A, IL2RG, IL7R, and IL23R.

What conditions are related to genes in the IL gene family?

Genetics Home Reference includes these conditions related to genes in the IL gene family:

  • ankylosing spondylitis
  • Crohn disease
  • idiopathic inflammatory myopathy
  • multiple sclerosis
  • psoriatic arthritis
  • ulcerative colitis
  • X-linked severe combined immunodeficiency

Where can I find additional information about the IL gene family?

You may find the following resources about the IL gene family helpful.

  • Eurekah Bioscience Collection: Pro-Inflammatory Cytokines ( (U.S. National Library of Medicine)
  • Molecular Biology of the Cell (fourth edition, 2002): Properties of Some Interleukins ( (U.S. National Library of Medicine)
  • National Cancer Institute: Biological Therapies for Cancer (

What glossary definitions help with understanding the IL gene family?

arthritis ; autoimmunity ; B-lymphocytes ; cancer ; cell ; chronic ; immune system ; inflammation ; joint ; kidney ; melanoma ; psoriasis ; receptor ; spondylitis ; subunit

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


These sources were used to develop the Genetics Home Reference summary for the IL gene family.

  • Kovanen PE, Leonard WJ. Cytokines and immunodeficiency diseases: critical roles of the gamma(c)-dependent cytokines interleukins 2, 4, 7, 9, 15, and 21, and their signaling pathways. Immunol Rev. 2004 Dec;202:67-83. Review. (
  • Chen Q, Carroll HP, Gadina M. The newest interleukins: recent additions to the ever-growing cytokine family. Vitam Horm. 2006;74:207-28. Review. (
  • Eklund JW, Kuzel TM. A review of recent findings involving interleukin-2-based cancer therapy. Curr Opin Oncol. 2004 Nov;16(6):542-6. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: February 2011
Published: February 8, 2016