TGFB1 and Thrombocytopenia: Anti-GARP monoclonal antibody PIIO-1 proved to be an effective and safe strategy to block TGF-β activation in preclinical models, for it specifically bound to ligand-free GARP on Tregs but lacked recognition of GARP-latent TGF-β complex on platelets, actually avoiding the risk of platelet-related toxicities such as thrombocytopenia.