Project Team

Henry VanBrocklin PhD, Professor of Radiology and Biomedical Imaging, University of California San Francisco

Timothy Henrich MD, MMSc, Associate Professor of Medicine, University of California San Francisco 

Michael Peluso MD, MPH, DTMH, Assistant Adjunct Professor of Infectious Diseases, University of California San Francisco

Robert Flavel MD, PhD, Chief of Molecular Imaging and Therapeutics Clinical Section in the Department of Radiology and Biomedical Imaging, University of California San Francisco

Steven Deeks, MD, Professor of Medicine in Residence, University of California San Francisco

Ramsey Badawi PhD, Professor of Radiology and Biomedical Engineering, University of California Davis

Project background:

Project investigator Dr. Henry VanBrocklin

A study using multimodal PET imaging to measure T cell activiation throughout the bodies and brains of Long COVID study participants. Tissue samples from the gut wall are also collected from participants via a biopsy procedure. These samples are analyzed for cellular immune responses, viral RNA/proteins, and gene expression changes. Data from the tissue samples is correlated with immune activation data from the imaging, allowing for extended validation of both techniques.

Project background:

Full body PET imaging can identify infectious and immune activity throughout the human body. Members of the project team have extensive experience in the development of PET imaging techniques, including over 25 years’ experience with the preparation and application of the radiopharmaceuticals used in molecular imaging. As part of this work, they have developed whole-body positron emission tomography (PET) imaging using a novel radiopharmaceutical agent, [18F]F-AraG, a highly selective tracer that allows for anatomical quantitation of activated T lymphocytes. They have previously used 18F]F-AraG to quantify T cell activation in body sites such as the lymph nodes in patients with HIV.

T cell activation in body sites such as bone marrow in post-COVID participants imaged by the project team

Now, the team is moving the same imaging framework into Long COVID. Pilot work thus far using [18F]F-AraG in Long COVID demonstrates tracer uptake in many anatomical regions, including the brain stem, spinal cord, bone marrow, nasopharyngeal and hilar lymphoid tissue, cardiopulmonary tissues, and gut wall compared to pre-pandemic controls. Tracer uptake is increased in participants imaged up to 2.5 years following SARS-CoV-2 infection. Thus far, the team has also found that T cell activation in the spinal cord and gut wall associate mostly strongly with the presence of Long COVID symptoms.

The [18F]F-AraG imaging study is ongoing, with more Long COVID participants being screened and imaged on a regular basis. Importantly, [18F]F-AraG imaging is being performed on Long COVID patients in several clinical trials. These trials are being run via the PolyBio-supported LIINC study which has been following patients after COVID-19 since April of 2020. They include a trial of investigational SARS-CoV-2 specific monoclonal antibody AER002, and a trial of Shionogi’s antiviral ensitrelvir. The ability to measure T cell activation via [18F]F-AraG imaging in trial participants will help determine the degree to which the therapeutics are successfully lowering Long COVID-associated inflammation.