MRC1 and Down syndrome: Interestingly, 68Ga-labeled anti-MMR Nbs recognizing the human homologue of MMR 36 are currently being evaluated in two clinical trials (NCT04168528 and NCT04758650) as tracers for the imaging of MMR+ macrophages via PET/CT in patients with oncological lesions, cardiovascular atherosclerosis, syndrome with abnormal immune activation and cardiac sarcoidosis.