THPO and autoimmune thrombocytopenic purpura: Similarly, in ITP (idiopathic thrombocytopenic purpura), treatment with thrombopoietin and its analogues (EltrombopagR, RhomiplostimR) leads to release of TGF-β, bFGF and PDGF by megakaryocytes and platelets within the marrow producing fibrosis in some patients on long-term therapy [1–3].