Identifying Biomarkers of Crohn’s Disease: IL23

Inflammatory bowel disease (IBD) comprises a group of chronic gastrointestinal disorders marked by digestive tract inflammation. IBD affects millions of individuals worldwide, with almost 5 million cases in 2019 alone.¹

One of the main types of IBD is Crohn’s disease, which can cause inflammation in any part of the digestive tract. Individuals with this disorder commonly experience abdominal pain, diarrhea and fatigue.² Crohn’s disease is characterized by alternating periods of active inflammation and remission, making it a complex and challenging condition to manage.³ While the exact cause remains unclear, it is believed to result from a combination of genetic, environmental, and immune system factors.

In Crohn’s disease, biomarkers such as C-reactive protein (CRP) and fecal calprotectin are pivotal for diagnosis and treatment guidance.⁴ However, such biomarkers have limitations including measurement variability, non-specificity and the lack of a definitive biomarker for Crohn’s disease. As a result, ongoing research is necessary to identify more precise and sensitive markers, standardize methods, and integrate multiple diagnostic approaches. This concerted effort aims to improve the reliability of diagnosis, treatment response and the progression of Crohn’s disease.

By utilizing Causaly, over 1700 biomarkers associated with the progression of Crohn’s disease were identified. Of these, about 200 were signaling proteins. Approximately 50 of these signaling proteins have been reported in clinical trials publications.

Prioritizing biomarkers further by those reported in the last 5 years revealed around 20 potential biomarkers. Biomarkers were then refined by the linguistic strength of evidence, from which interleukin-23 (IL23) stood out as an interesting biomarker.

IL23 is a heterodimeric cytokine is primarily produced by immune cells, such as dendritic cells and macrophages. This interleukin influences various immune cells, notably T cells and natural killer cells and is linked to the development of certain autoimmune and inflammatory diseases.

IL23 has shown to promote the proliferation and differentiation of IL17A- and IL22-producing T helper cells.⁵ This is important because Crohn’s disease patients have elevated levels of IL17A and IL22 producing T cells compared to the healthy control group,⁶ highlighting the significant of IL23 in this disease. In a more recent study, it was suggested that the diagnostic accuracy of IL23 might be linked to the IL17 and IL23 axis in the pathogenesis of Crohn’s disease.⁷

IL23 has emerged as a promising biomarker for Crohn’s disease, given its integral role in driving chronic inflammation and its specific association with disease pathogenesis. Research demonstrates elevated IL23 levels in patients with Crohn’s disease, suggesting its potential as a diagnostic and monitoring tool. Monitoring IL23 levels could therefore provide valuable insights for diagnosis, disease monitoring, and guiding treatment decisions.