Immuno-imaging in solid organ transplantation

Organ transplantation is a life-saving treatment for patients with end-stage organ failure. However, graft rejection remains a major challenge despite advances in immunosuppression. The current gold standard for diagnosing graft rejection involves invasive tissue biopsies, which can be risky for certain patients. Biopsies also provide no spatiotemporal information, limiting insight into the dynamic immune processes driving graft rejection. Immuno-imaging is increasingly explored as a noninvasive tool to diagnose graft rejection and evaluate treatment efficacy. However, the clinical application of this approach remains limited. In this review, we described how various imaging techniques can illuminate graft-related immune responses in solid organ transplantation. We discussed the progress made in biomarker identification and tracer development, including those informing on metabolic processes, immune cell dynamics, and antibody responses. We also compared immuno-imaging with other minimally invasive techniques for diagnosing graft rejection and described our vision for how it can be best integrated into the clinic.