CD45-PET is a robust, non-invasive tool for imaging inflammation, 2025, Ali Salehi Farid et al

Abstract
Imaging inflammation holds immense potential for advancing the diagnosis, treatment and prognosis of many conditions. The lack of a specific and sensitive positron emission tomography (PET) probe to detect inflammation is a critical challenge.

To bridge this gap, we present CD45-PET imaging, which detects inflammation with exceptional sensitivity and clarity in several preclinical models. Notably, the intensity of the CD45-PET signal correlates robustly with the severity of disease in models of inflammatory lung and bowel diseases, outperforming 18F-fluorodeoxyglucose PET, the most widely used imaging modality for inflammation globally. Longitudinal CD45-PET imaging further enables precise monitoring of dynamic changes in tissue-specific inflammatory profiles.

Finally, we developed a human CD45-PET probe for clinical translation that effectively detects human immune cells in a humanized mouse model. CD45-PET imaging holds substantial clinical promise, offering a tool for guiding diagnostic and therapeutic decisions for inflammatory diseases through a precise, whole-body assessment of the inflammation profiles of individual patients.
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Dana-FarberD Scientists Develop PET Probe to Image Inflammation with High Sensitivity

Summary: Researchers at Dana-Farber Cancer Institute have developed a breakthrough method to detect inflammation in the body using positron emission tomography (PET) imaging. This innovative probe targets CD45, a marker abundantly expressed on all immune cells but absent from other cell types. In healthy animals, the probe provides remarkably clear images of immune system organs such as bone marrow, spleen, and lymph nodes. In disease models, it reveals inflammation in affected organs, such as the colon in inflammatory bowel disease and the lungs in acute respiratory distress syndrome. The researchers found that the inflammation severity shown by CD45-PET correlates with both microscopic tissue analysis and clinical symptoms. They also developed a human CD45-PET probe and demonstrated its ability to detect human immune cells in a humanized mouse model. Furthermore, in animal models of graft-versus-host disease – a serious condition following bone marrow transplants – the human CD45-PET probe showed potential for early detection and precise localization of the disease, which can manifest in various body parts. The team is now working toward initiating clinical trials to validate their human CD45-PET probe.

Significance: Inflammation is a sign that the immune system is actively defending the body against disease. However, prolonged and excessive inflammation can become pathological and is a key factor in many chronic diseases, such as cardiovascular diseases, cancer, and diabetes, which collectively contribute to a significant portion of global mortality. Currently, there are no non-invasive tools to reliably detect and pinpoint inflamed areas within the body. The developed CD45-PET probe is the first to identify inflammation generally and with high sensitivity through whole-body imaging.

Once validated in humans, this tool could have immediate clinical applications, guiding the selection of anti-inflammatory treatments, monitoring responses to anti-inflammatory medications and cancer immunotherapies, and aiding in the diagnosis of conditions with known inflammatory underpinnings.
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