A novel strategy utilizing Gallium (Ga)-68–DOTA-ZCAM241 positron-emission tomography/computed tomography (PET/CT) may effectively detect CD69-positive immune cells prior to symptom development in patients with early rheumatoid arthritis, according to a preclinical study published by Puuvuori et al in The Journal of Nuclear Medicine. Researchers transferred splenocytes from KRN T-cell receptor transgenic B6 mice into T-cell–deficient I-Ag7 major histocompatibility complex class II–expressing recipient mice. They examined the mice using Ga-68–DOTA-ZCAM241 PET/CT prior to and at 3, 7, and 12 days following the induction of arthritis; evaluated them for clinical indicators of arthritis (including body weight changes and swelling in the paws); and analyzed tissue biopsy samples for CD69 expression using flow cytometry and immunostaining. They then performed PET scans with a nonbinding, size-matched Affibody molecule as a control in a second group of mice. The mice presented with clinical indicators of disease 5 to 7 days after induction, and uptake of Ga-68–DOTA-ZCAM241 in the joints increased following induction. On the third day after induction, prior to the presence of arthritis symptoms, researchers detected an elevated PET signal. The researchers confirmed the presence of CD69-positive immune cells in the joints and lymph nodes of the mice. Further, the uptake of the control in the second group of mice increased with disease progression, but to a lesser extent when compared with Ga-68–DOTA-ZCAM241. In a companion press release on the findings from the Society of Nuclear Medicine & Molecular Imaging, the study authors concluded: “Ga-68–DOTA-ZCAM241 is a potential candidate for PET imaging of activated immune cells during rheumatoid arthritis onset. [W]e hope this technology will be broadly used in many diseases that involve activated immune cells and inflammation.”
February 29, 2024