This radiopharmaceutical is a promising candidate for monitoring tumours immunotherapy in the clinic.350 Simonetta et al. developed [64Cu]Cu-DOTA-mAbOX40, which can act as an immunoPET tracer to achieve specific imaging of OX40+-activated T-cells in a mouse model of acute graft versus host disease (GVHD), which is a systemic disease characterized by multisystem damage (skin, oesophagus, gastrointestinal, liver, etc.)that occurs after bone marrow transplantation (BMT).351 Nobashi et al. developed an [89Zr]Zr-DFO-OX40 mAb to detect OX40+ activated T cells in a murine orthotopic glioma model. Here, TNFRSF4 is linked to acute graft versus host disease.