Explore our research into novel biomarker testing
Interleukin-18 (IL-18) is a pro-inflammatory cytokine that, in collaboration with IL-12, promotes Th1-type immune responses, which help to protect the body from infection. In the absence of IL-12, IL-18 switches to promote Th2 immune responses, which drive allergic inflammation. In healthy individuals, circulating IL-18 levels are generally low, with >95% bound to IL-18-binding protein, which neutralises its activity. However, increased levels have been observed across a broad range of conditions featuring immune dysfunction and inflammation, including autoimmune conditions, allergic disorders and metabolic diseases.
-alt.jpg)
Increased production of IL-18 may be associated with overactivity of the immune system and the development of autoimmune or chronic inflammatory diseases. Elevated IL-18 levels may also reflect allergic inflammation and have been linked to conditions such as dermatitis and asthma. In addition, some evidence suggests that IL-18 concentrations may be increased in individuals with depression. Due to its pro-inflammatory properties, IL-18 has been implicated in the chronic low-grade inflammation that characterises cardiometabolic disorders, including obesity, type 2 diabetes, metabolic syndrome, and cardiovascular disease. High IL-18 levels have been observed in these conditions and may help identify individuals at greater risk of developing cardiovascular disease.
Elevate your healthcare provider experience. Speak with us today to discuss your health service needs.
Amphiregulin
arrow_forward_iosHeparin-Binding EGF-Like Growth Factor (HB-EGF)
arrow_forward_iosTransforming Growth Factor Alpha (TGF-α)
arrow_forward_iosDickkopf-1 (DKK-1)
arrow_forward_iosProgrammed Cell Death Protein 1 (PD-1)
arrow_forward_iosMesothelin
arrow_forward_iosSoluble Receptor for Advanced Glycation End Products (sRAGE)
arrow_forward_iosGalectin-3
arrow_forward_iosMonomeric CRP (mCRP)
arrow_forward_iosFree PSA Isoforms
arrow_forward_iosAbdel-Bary, A. E. (2022). Serum interleukin-18 and immunoglobulin E in chronic spontaneous urticaria and their relation to severity of the disease. Journal of the Egyptian Women’s Dermatologic Society, 88-93.Al-Hakeim, H. K. (2015). IL-6, IL-18, sIL-2R, and TNFα proinflammatory markers in depression and schizophrenia patients who are free of overt inflammation. Journal of Affective Disorders, 182, 106–114.Angelova, P. K. (2018). Interleukin-18 and testosterone levels in men with metabolic syndrome. The Aging Male, 130-137.Aral, M. A. (2006). The relationship between serum levels of total IgE, IL-18, IL-12, IFN-gamma and disease severity in children with atopic dermatitis. Mediators of Inflammation, 73098.Arican, O. A. (2005). Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-8, IL-12, IL-17, and IL-18 in patients with active psoriasis and correlation with disease severity. Mediators of Inflammation, 273–279.Aso, Y. O. (2003). Relationships of plasma interleukin-18 concentrations to hyperhomocysteinemia and carotid intimal-media wall thickness in patients with type 2 diabetes. Diabetes Care, 2622-2627.Bai, F. Z. (2017). Serum levels of adipokines and cytokines in psoriasis patients: a systematic review and meta-analysis. Oncotarget, 1266–1278.Beurel, E. T. (2020). The bidirectional relationship of depression and inflammation: double trouble. Neuron, 234-256.Blankenberg, S. L. (2003). Interleukin-18 and the risk of coronary heart disease in European men: the Prospective Epidemiological Study of Myocardial Infarction (PRIME). Circulation, 108(20), 2453–2459.Blankenberg, S. T. (2002). Interleukin-18 is a strong predictor of cardiovascular death in stable and unstable angina. Circulation, 24-30.Bossù, P. P. (2015). Hippocampal volume and depressive symptoms are linked to serum IL-18 in schizophrenia. Neurology(R) Neuroimmunology & Neuroinflammation, 2(4), e111.Bresnihan, B. R. (2002). Serum interleukin 18 and interleukin 18 binding protein in rheumatoid arthritis. Annals of the Rheumatic Diseases, 726-729.Chen, M. C. (2007). Interleukin-18: a strong predictor of the extent of coronary artery disease in patients with unstable angina. Heart and Vessels, 22(6), 371–375.Chen, O. S. (2013). The imbalance of IL-18/IL-18BP in patients with systemic juvenile idiopathic arthritis. Acta Biochimica et Biophysica Sinica, 339–341.Colafrancesco, S. P. (2012). IL-18 Serum Level in Adult Onset Still's Disease: A Marker of Disease Activity. International Journal of Inflammation, 2012, 156890.El-Tantawy, A. M. (2008). Psychiatric morbidity associated with some cytokines (IL-1beta, IL-12, IL-18 and TNF-alpha) among rheumatoid arthritis patients. The Egyptian Journal of Immunology, 15(1), 1–11.Escobar-Morreale, H. F. (2004). Serum interleukin-18 concentrations are increased in the polycystic ovary syndrome: relationship to insulin resistance and to obesity. The Journal of Clinical Endocrinology and Metabolism, 806-811.Esposito, K. N. (2003). Cytokine milieu tends toward inflammation in type 2 diabetes. Diabetes Care, 1647.Evans, J. C. (2007). The association of interleukin-18 genotype and serum levels with metabolic risk factors for cardiovascular disease. European Journal of Endocrinology, 633-640.Forouzandeh, M. B. (2020). The inflammasome signaling proteins ASC and IL-18 as biomarkers of psoriasis. Frontiers in Pharmacology, 1238.Gangemi, S. M. (2003). Serum levels of interleukin-18 and s-ICAM-1 in patients affected by psoriasis: preliminary considerations. Journal of the European Academy of Dermatology and Venereology, 42–46.Girard, C. R. (2016). Elevated serum levels of free interleukin-18 in adult-onset Still's disease. Rheumatology (Oxford, England), 55(12), 2237–2247.Gualberto Cardoso, P. R. (2021). Interleukin-18 in Brazilian rheumatoid arthritis patients: can Leflunomide reduce it? Autoimmune Diseases, 6672987.Hartford, M. W. (2010). Interleukin-18 as a predictor of future events in patients with acute coronary syndromes. Arteriosclerosis, Thrombosis, and Vascular Biology, 30(10), 2039–2046.Imaoka, H. G. (2011). Interleukin-18 and interleukin-18 receptor-α expression in allergic asthma. The European Respiratory Journal, 981–983.Italiani, P. M. (2018). IL-1 family cytokines and soluble receptors in systemic lupus erythematosus. Arthritis Research & Therapy, 27.Jafari-Nakhjavani, M. R. (2016). Correlation of plasma interleukin-18 concentration and severity of renal involvement and disease activity in systemic lupus erythematosus. Journal of Nephropathology, 28-33.Jefferis, B. J. (2011). Interleukin 18 and coronary heart disease: prospective study and systematic review. Athersclerosis, 227-233.Jelusić, M. L. (2007). Interleukin-18 as a mediator of systemic juvenile idiopathic arthritis. Clinical Rheumatology, 1332–1334.Kabakchieva, P. G. (2022). Elevated levels of interleukin-18 are associated with several indices of general and visceral adiposity and insulin resistance in women with polycystic ovary syndrome. Archives of Endocrinology and Metabolism, 3-11.Kaplanski, G. (2018). Interleukin-18: Biological properties and role in disease pathogenesis. Immunological Reviews, 281(1), 138–153.Kawashima, M. Y. (2001). Levels of interleukin-18 and its binding inhibitors in the blood circulation of patients with adult-onset Still's disease. Arthritis and Rheumatism, 44(3), 550–560.Kim, H. A. (2012). Serum S100A8/A9, but not follistatin-like protein 1 and interleukin 18, may be a useful biomarker of disease activity in adult-onset Still's disease. The Journal of Rheumatology, 39(7), 1399–1406.Kokai, M. K. (2002). Plasma interleukin-18 levels in patients with psychiatric disorders. Journal of Immunotherapy (Hagerstown, Md. : 1997), 25 Suppl 1, S68–S71.Kou, K. A. (2012). Association of serum interleukin-18 and other biomarkers with disease severity in adults with atopic dermatitis. Archives of Dermatological Research, 305–312.Kubysheva, N. B. (2020). Relationship of serum levels of IL-17, IL-18, TNF-alpha, and lung function parameters in patients with COPD, asthma-COPD overlap and bronchial asthma. Mediators of Inflammation, 1-11.Kudela, H. D. (2019). Comparative study of Interleukin-18 (IL-18) serum levels in adult onset Still's disease (AOSD) and systemic onset juvenile idiopathic arthritis (sJIA) and its use as a biomarker for diagnosis and evaluation of disease activity. BMC Rheumatology, 4.Kurt, E. A. (2011). Autologous serum skin test response in chronic spontaneous urticaria and respiratory diseases and its relationship with serum interleukin-18 level. Archives of Dermatological Research, 643–649.Landy, E. C. (2024). Biological and clinical roles of IL-18 in inflammatory diseases. Nature Reviews Rheumatology, 33–47.Lee, Y. H. (2025). Associations between circulating interleukin-18 levels and adult-onset Still's disease: a meta-analysis. Journal of Rheumatic Diseases, 32(1), 48–56.Liu, X. Q. (2023). Circulating inflammatory cytokines and psoriasis risk: A systematic review and meta-analysis. PloS One, e0293327.Lotito, A. P. (2007). Interleukin 18 as a marker of disease activity and severity in patients with juvenile idiopathic arthritis. The Journal of Rheumatology, 823–830.Luo, Y. H. (2016). Altered serum levels of TNF-α, IL-6 and IL-18 in manic, depressive, mixed state of bipolar disorder patients. Psychiatry Research, 244, 19–23.Luo, Y. H. (2019). Changes in serum TNF-α, IL-18, and IL-6 concentrations in patients with chronic schizophrenia at admission and at discharge. Comprehensive Psychiatry, 90, 82–87.Mende, R. V. (2018). Analysis of serum interleukin (IL)-1Beta and IL-18 in systemic lupus erythematosus. Frontiers in Immunology.Merendino, R. A. (2002). Interleukin-18 and CD30 serum levels in patients with moderate-severe depression. Mediators of Inflammation, 11(4), 265–267.Migliorini, P. A. (2010). Serum and urinary levels of IL-18 and its inhibitor IL-18BP in systemic lupus erythematosus. European Cytokine Network, 264-271.Moriwaki, Y. Y. (2003). Elevated levels of interleukin-18 and tumor necrosis factor-alpha in serum of patients with type 2 diabetes mellitus: relationship with diabetic nephropathy. Metabolism, 605-608.Novick, D. E. (2010). High circulating levels of free interleukin-18 in patients with active SLE in the presence of elevated levels of interleukin-18 binding protein. Journal of Autoimmunity, 121-126.Ogłodek, E. (2017). The role of PON-1, GR, IL-18, and OxLDL in depression with and without posttraumatic stress disorder. Pharmacological Reports: PR, 69(5), 837–845.Ohnishi, H. K. (2003). Interleukin-18 is associated with the severity of atopic dermatitis. Allergology International, 52(3), 123-130.Ohya, T. N. (2022). Impaired interleukin-18 signaling in natural killer cells from patients with systemic juvenile idiopathic arthritis. ACR Open Rheumatology, 503–510.Osimo, E. F. (2020). Inflammatory markers in depression: A meta-analysis of mean differences and variability in 5,166 patients and 5,083 controls. Brain, Behavior, and Immunity, 87, 901–909.Park, D. S. (2007). Clinical significance of serum interleukin-18 concentration in the patients with atopic dermatitis. The Korean Journal of Laboratory Medicine, 128-132.Patil, S. P. (2011). Detection of immunological biomarkers correlated with asthma control and quality of life measurements in sera from chronic ashmatic patients. Annals of Allergy, Asthma & Immunology, 205-213.Pietrzak, A. L. (2003). Interleukin-18 levels in the plasma of psoriatic patients correlate with the extent of skin lesions and the PASI score. Acta Dermato-Venereologica, 83(4), 262–265.Pietrzak, D. P. (2018). Serum concentrations of interleukin 18 and 25-hydroxyvitamin D3 correlate witwith depression severity in men with psoriasis. PloS One, 13(8), e0201589.Priori, R. B. (2011). Markedly increased IL-18 liver expression in adult-onset Still's disease-related hepatitis. Rheumatology (Oxford, England), 50(4), 776–780.Priori, R. C. (2014). Interleukin 18: a biomarker for differential diagnosis between adult-onset Still's disease and sepsis. The Journal of Rheumatology, 41(6), 1118–1123.Puxeddu, I. I. (2013). Free IL-18 and IL-33 cytokines in chronic spontaneous urticaria. Cytokine, 741–743.Rabkin, S. W. (2013). Inflammatory biomarkers CRP, MCP-1, serum amyloid alpha and interleukin-18 in patients with HTN and dyslipidemia: impact of diabetes mellitus on metabolic syndrome and the effect of statin therapy. Hypertension Research, 550-558.Salas-Salvadó, J. D. (2019). Effect of a lifestyle intervention program with energy-restricted Mediterranean diet and exercise on weight loss and cardiovascular risk facors: one year results of the PREDIMED-Plus Trial. Diabetes Care, 777-788.Sanders, N. L. (2016). Role of interleukin-18 in the pathophysiology of allergic diseases. Cytokine & Growth Factor Reviews, 31-39.Sharma, P. S. (2020). To Evaluate the Role and Relevance of Cytokines IL-17, IL-18, IL-23 and TNF-α and Their Correlation with Disease Severity in Chronic Urticaria. Indian Dermatology Online Journal, 11(4), 594–597.Shimizu, M. Y. (2010). Distinct cytokine profiles of systemic-onset juvenile idiopathic arthritis-associated macrophage activation syndrome with particular emphasis on the role of interleukin-18 in its pathogenesis. Rheumatology (Oxford, England), 1645–1653.Sun, L. H. (2011). Lean body mass, interleukin 18 and metabolic syndrome in apparently healthy Chinese. PloS One.Szabo, A. O. (2022). Increased circulating IL-18 levels in severe mental disorders indicate systemic inflammasome activation. Brain, Behavior, and Immunity, 99, 299–306.Takahara, T. S. (2015). Serum IL-18 as a potential specific marker for differentiating systemic juvenile idiopathic arthritis from incomplete Kawasaki disease. Rheumatology International, 81–84.Takahashi, H. T. (2010). Serum cytokines and growth factor levels in Japanese patients with psoriasis. Clinical and Experimental Dermatology, 645–649.Tanaka, H. M. (2001). IL-18 might reflect disease activity in mild and moderate asthma exacerbation. The Journal of Allergy and Clinical Immunology, 331–336.Thorand, B. K. (2005). Elevated levels of interleukin-18 predict the development of type 2 diabetes: results from the MONICA/KORA Augsburg Study, 1984-2002. Diabetes, 54(10), 2932–2938.Trøseid, M. S. (2010). The role of interleukin-18 in the metabolic syndrome. Cardiovascular Diabetology, 9, 11.Trzeciak, M. G. (2011). Relationship between serum levels of interleukin-18, IgE and disease severity in patients with atopic dermatitis. Clinical and Experimental Dermatology, 36(7), 728–732.Tso, T. K. (2006a). Relationship of plasma interleukin-18 concentrations to traditional and non-traditional cardiovascular risk factors in patients with systemic lupus erythematosus. Rheumatology (Oxford, England), 1148-1153.Tso, T. K. (2006b). Elevation of plasma interleukin-18 concentration is associated with insulin levels in patients with systemic lupus erythematosus. Lupus, 207-212.Vasilev, G. M. (2021). The role of IL-18 in addition to Th17 cytokines in rheumatoid arthritis development and treatment in women. Scientific Reports, 15391.Wang, Q. Y. (2022). Cytokine Profiles and the Relationship of Disease Severity in Patients with Psoriasis. Indian Journal of Dermatology, 67(2), 204.Wong, C. K. (2000). Elevation of plasma interleukin-18 concentration is correlated with disease activity in systemic lupus erythematosus. Rheumatology (Oxford, England), 1078-1081.Wong, C. K. (2001). Proinflammatory cytokines (IL-17, IL-6, IL-18 and IL-12) and Th cytokines (IFN-gamma, IL-4, IL-10 and IL-13) in patients with allergic asthma. Clinical and Experimental Immunology, 177–183.Wong, C. K. (2002). Elevated production of interleukin-18 is associated with renal disease in patients with systemic lupus erythematosus. Clinical and Experimental Immunolgy, 345-351.Wu, C. Y. (2016). Serum IL-18 as a biomarker in predicting long-term renal outcome among pediatric-onset systemic lupus erythematosus patients. Medicine.Wu, J. W. (2024). Gasdermin D silencing alleviates airway inflammation and remodeling in an ovalbumin-induced asthmatic mouse model. Cell Death & Disease.Xia, Y. C. (2017). Extremely elevated IL-18 levels may help distinguish systemic-onset juvenile idiopathic arthritis from other febrile diseases. Brazilian Journal of Medical and Biological Research, e5958.Yang, L. Z. (2010). The serum interleukin-18 is a potential marker for development of post-stroke depression. Neurological Research, 340–346.Yasuda, K. N. (2019). Interleukin-18 in Health and Disease. International Journal of Molecular Sciences, 20(3), 649.Zedan, K. R. (2015). Immunoglobulin E, interleukin-18 and interleukin-12 in patients with atopic dermatitis: correlation with disease activity. Journal of Clinical and Diagnostic Research, WC01–WC05.