Kiru L, Zlitni A, Tousley AM, et al. In Vivo Imaging of Nanoparticle-Labeled CAR T Cells. Proceedings of the National Academy of Sciences. 2022; (doi: 10.1073/pnas.2102363119).
Researchers have identified a successful method for mechanically labeling antigen receptor (CAR) T cells, a development that promises to expand the use of T cell therapy to include solid tumors. The noninvasive technique stamps CAR T cells with ferumoxytol, iron oxide nanoparticles that can then be detected using magnetic resonance imaging, photoacoustic imaging, and magnetic particle imaging. In animal testing, these clinical imaging methods successfully directed T cells to osteosarcomas and off-target sites in subjects that had received infusions of T cells marked with the Food and Drug Administration-approved nanoparticles. In turn, T cells were not visualized in animals infused with unlabeled cells. The ability to track the therapeutic T cells in the tumor is an important advance in the quest to apply CAR T-cell therapy to solid tumors, which has been hindered by the absence of data on the biodistribution of the therapeutic cells in patients. The process described by investigators can be used to monitor T cells during the course of clinical trials.