In vivo PET imaging of the activated immune environment in a small animal model of inflammatory arthritis

BL Franc, S Goth, J MacKenzie, X Li… - Molecular …, 2017 - journals.sagepub.com
BL Franc, S Goth, J MacKenzie, X Li, J Blecha, T Lam, S Jivan, RA Hawkins, H VanBrocklin
Molecular imaging, 2017journals.sagepub.com
Background: Evolving immune-mediated therapeutic strategies for rheumatoid arthritis (RA)
may benefit from an improved understanding of the complex role that T-cell activation plays
in RA. This study assessed the potential of fluorine-18-labeled 9-β-d-
arabinofuranosylguanine ([18F] F-AraG) positron emission tomography (PET) imaging to
report immune activation in vivo in an adjuvant-induced arthritis (AIA) small animal model.
Methods: Using positron emission tomography–computed tomography imaging, uptake of …
Background
Evolving immune-mediated therapeutic strategies for rheumatoid arthritis (RA) may benefit from an improved understanding of the complex role that T-cell activation plays in RA. This study assessed the potential of fluorine-18-labeled 9-β-d-arabinofuranosylguanine ([18F]F-AraG) positron emission tomography (PET) imaging to report immune activation in vivo in an adjuvant-induced arthritis (AIA) small animal model.
Methods
Using positron emission tomography–computed tomography imaging, uptake of [18F]F-AraG in the paws of mice affected by arthritis at 6 (acute) and 20 (chronic) days following AIA induction in a single paw was assessed and compared to uptake in contralateral control paws. Fractions of T cells and B cells demonstrating markers of activation at the 2 time points were determined by flow cytometry.
Results
Differential uptake of [18F]F-AraG was demonstrated on imaging of the affected joint when compared to control at both acute and chronic time points with corresponding changes in markers of T-cell activation observed on flow cytometry.
Conclusion
[18F]F-AraG may serve as an imaging biomarker of T-cell activation in inflammatory arthritis. Further development of this technique is warranted and could offer a tool to explore the temporal link between activated T cells and RA as well as to monitor immune-mediated therapies for RA in clinical trials.
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