A novel anti-CD154 antibody, RD-05, with a genetically modified human IgG4 Fc inhibits B cell activation and antibody formation with no adverse effects of thromboembolism in mice, suggesting clinical applications in AMR as well as antibody-mediated autoimmune diseases including systemic lupus erythematosus (SLE) or idiopathic thrombocytopenic purpura (ITP) [125]. The gene discussed is CD40LG; the disease is autoimmune thrombocytopenic purpura.