First-in-human immunoPET imaging of COVID-19 convalescent patients using dynamic total-body PET and a CD8-targeted minibody

With most of the T cells residing in the tissue, not the blood, developing noninvasive methods for in vivo quantification of their biodistribution and kinetics is important for studying their role in immune response and memory. This study presents the first use of dynamic positron emission tomography (PET) and kinetic modeling for in vivo measurement of CD8⁺ T cell biodistribution in humans. A ⁸⁹Zr-labeled CD8-targeted minibody (⁸⁹Zr-Df-Crefmirlimab) was used with total-body PET in healthy individuals (N = 3) and coronavirus disease 2019 (COVID-19) convalescent patients (N = 5).

Kinetic modeling results aligned with T cell–trafficking effects expected in lymphoid organs. Tissue-to-blood ratios from the first 7 hours of imaging were higher in bone marrow of COVID-19 convalescent patients compared to controls, with an increasing trend between 2 and 6 months after infection, consistent with modeled net influx rates and peripheral blood flow cytometry analysis. These results provide a promising platform for using dynamic PET to study the total-body immune response and memory.

Source: Omidvari N, Jones T, Price PM, Ferre AL, Lu J, Abdelhafez YG, Sen F, Cohen SH, Schmiedehausen K, Badawi RD, Shacklett BL, Wilson I, Cherry SR. First-in-human immunoPET imaging of COVID-19 convalescent patients using dynamic total-body PET and a CD8-targeted minibody. Sci Adv. 2023 Oct 13;9(41):eadh7968. doi: 10.1126/sciadv.adh7968. Epub 2023 Oct 12. PMID: 37824612; PMCID: PMC10569706. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10569706/ (Full text)