Usefulness of thrombopoietin in the diagnosis of peripheral thrombocytopenias

Background and Objective. Thrombocytopenia of peripheral origin is basicall y due to platelet destruction or splenic sequestration. Thrombopoietin (TPO ) regulates platelet production stimulating megakaryocyte proliferation and maturation. The evaluation of TPO levels may be a useful tool in the diagn osis of thrombocytopenias of unknown origin. We tried to determine the valu e of TPO levels in some thrombocytopenias classically considered as periphe ral. Design and Methods. Serum TPO levels and platelet counts were measured in 3 2 thrombocytopenic patients with liver cirrhosis (LC) and 23 with chronic h epatitis C (CHC) viral infection, in 54 patients with a clinical and serolo gical diagnosis of autoimmune thrombocytopenic purpura (AITP), and in 88 pa tients infected with the human immunodeficiency virus (HIV). Results. Patients with LC, AITP and HIV had lower platelet counts than pati ents with CHC. The degree of thrombocytopenia did not, however, correlate w ith the TPO levels. HIV Infected patients (246+/-304 pg/mL) and AITP patien ts (155+/-76 pg/mL) had higher TPO levels than controls (121+/-58 pg/mL). T PO levels in patients with CHC (125+/-40 pg/mL) did not differ from those I n control subjects, but were slightly decreased in patients with LC (104+/- 56 pg/mL). Interpretation and Conclusions. Reduced TPO production could be involved in the development of thrombocytopenia in LC patients, but not in patients wi th early stages of CHC viral Infection. HIV and AITP patients had slightly raised levels of TPO. As TPO levels are normal or slightly increased in mos t peripheral thrombocytopenias, these data alone are not sufficient to dist inguish the different types of peripheral thrombocytopenia. They may, howev er, be a useful tool for differentiating some central and peripheral thromb ocytopenias. (C) 1999, Ferrata Storti Foundation.