Detection of IL23p40 via Positron Emission Tomography Visualized Inflammatory Bowel Disease

Background and aims Inflammatory bowel disease (IBD), which includes both Crohn’s Disease (CD) and ulcerative colitis (UC), is a relapsing inflammatory disease of the gastrointestinal (GI) tract. Long term chronic inflammatory conditions elevate patients’ risk for colorectal cancer (CRC). Currently, diagnosis requires endoscopy with biopsy. This procedure is invasive and requires bowel preparatory regimen, adding to patient burden. Interleukin 23 (IL23) plays a key role in inflammation especially in the pathogenesis of IBD and is an established therapeutic target. We propose that imaging of IL23 via immunopositron emission tomography (immunoPET) will potentially lead to a new non-invasive diagnostic approach.

Methods The aim of the present study is to investigate the potential of immunoPET to image inflammation in a chemically induced mouse model of colitis using dextran sodium sulfate (DSS) by targeting IL23 via its p40 subunit with a ⁸⁹Zr-radiolabeled α-IL23p40 antibody.

Results High uptake of the IL23p40 immunoPET agent in mice were displayed in DSS-administered mice, which correlated with increased IL23p40 present in sera. Competitive binding studies confirmed the specificity of the radiotracer for IL23p40 in the GI tract.

Conclusion Taken together, these promising results set the stage for developing this radiotracer as an imaging biomarker for IBD diagnosis. Noninvasive imaging of IBD with IL23p40 immunoPET may help physicians in their treatment decisions for IBD management.