[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Immunology](https://durgical.com/en/immunology/) › [Cytokines and molecules](https://durgical.com/en/immunology/#a-molecules) › Interleukin-1 [Immunology](https://durgical.com/en/immunology/) · [Cytokines and molecules](https://durgical.com/en/immunology/#a-molecules) # Interleukin-1 - Molecule IL-1 is an alarm cytokine made by macrophages: it causes fever and inflammation, and its excess drives rare inherited fever syndromes. Updated 2026-11-01 ## Key points - Main source: activated macrophages and monocytes; IL-1β needs the inflammasome and caspase-1 to become active. - Endogenous pyrogen together with IL-6 and TNF-α. - The body makes its own blocker, IL-1 receptor antagonist (IL-1Ra); its genetic absence causes DIRA. - Autoinflammatory diseases (cryopyrin-associated periodic syndromes, FMF, TRAPS, MKD) respond to IL-1 blockade. - Drugs: anakinra (recombinant IL-1Ra), canakinumab (anti-IL-1β antibody), rilonacept (soluble trap). ## What it is Interleukin-1 is a family of cytokines; the two classic members are IL-1α and IL-1β, which share one signalling receptor (IL-1R1). IL-1β is made as an inactive precursor that must be cut by caspase-1, activated inside a protein complex called the inflammasome (NLRP3 is the best known). It is a central driver of fever and acute inflammation, and blocking it controls autoinflammatory diseases. ## Structure - IL-1α: often stays inside or on the cell and acts as an alarm signal released by damaged cells. - IL-1β: secreted after caspase-1 cleaves its precursor (pro-IL-1β). - Receptor: IL-1R1, which signals through MyD88, IRAK and TRAF6 to switch on NF-κB. ## Function - Raises the hypothalamic set point (fever). - Activates endothelium so leukocytes can stick and leave the vessel. - Induces other cytokines (IL-6, chemokines such as IL-8) and matrix-degrading enzymes. - Contributes to systemic inflammation in sepsis. ## Clinical notes - Cryopyrin-associated periodic syndromes (gain of function of NLRP3): fever, urticaria-like rash, joint pain; treated with IL-1 blockers. - Familial Mediterranean fever: IL-1 blockade is an option when colchicine fails or is not tolerated. - Gout: urate crystals activate the inflammasome; canakinumab is approved for difficult flares. - Still disease and systemic juvenile idiopathic arthritis: IL-1 blockers are used; macrophage activation syndrome is a feared complication. - IL-1 blockers raise the risk of infections; latent tuberculosis is screened for before canakinumab. ## Memory aid IL-1 is the first match: it is struck inside the inflammasome and sets the fever alight. ## Test yourself Think of the answer, then tap the question to see it. ## Which enzyme converts pro-IL-1β to its active form? Caspase-1, activated inside the inflammasome (for example NLRP3). ## What is anakinra? A recombinant form of the natural IL-1 receptor antagonist; it competes with IL-1α and IL-1β for IL-1R1. ## Which group of diseases shows the best response to IL-1 blockade? Autoinflammatory diseases such as cryopyrin-associated periodic syndromes, FMF, TRAPS and mevalonate kinase deficiency. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/immunology/interleukin-1/) ## Related - [Cytokines: the table to know](https://durgical.com/en/immunology/cytokines-the-table-to-know/) - [Interleukin-6](https://durgical.com/en/immunology/interleukin-6/) - [TNF-α](https://durgical.com/en/immunology/tnf/) - [IL-8 and the chemokines](https://durgical.com/en/immunology/il-8-and-the-chemokines/) - [Acute-phase response and fever (CRP, ESR, procalcitonin)](https://durgical.com/en/immunology/acute-phase-response-and-fever/) - [Acute inflammation: vascular and cellular events](https://durgical.com/en/immunology/acute-inflammation-vascular-and-cellular-events/) - [Monocyte and macrophage](https://durgical.com/en/immunology/monocyte-and-macrophage/) - [Pattern recognition: PAMPs, DAMPs, Toll-like receptors](https://durgical.com/en/immunology/pattern-recognition-pamps-damps-toll-like-receptors/) ## Related conditions - [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/) ## In Pharmacology - [Anakinra](https://durgical.com/en/pharmacology/anakinra/) [← All of immunology](https://durgical.com/en/immunology/) Educational content on the immune system; not a treatment or individual vaccination guide and no substitute for a health professional's advice. No doses are given. Sources: [Targeting IL-1β in the Treatment of Atherosclerosis](https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.589654/full) (Frontiers in Immunology, 2020); [Pro-Inflammatory and Anti-Inflammatory Interleukins in Infectious Diseases: A Comprehensive Review](https://pmc.ncbi.nlm.nih.gov/articles/PMC10818686/) (Tropical Medicine and Infectious Disease (PubMed Central), 2024); [Canakinumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a622024.html) (MedlinePlus (U.S. National Library of Medicine), 2025); [Rilonacept Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a622030.html) (MedlinePlus (U.S. National Library of Medicine), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/immunology/interleukin-1/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/immunology/interleukin-1/