Plasma thrombopoietin concentrations in thrombocytopenic and non-thrombocytopenic patients in a neonatal intensive care unit

Thrombocytopenia is a frequent occurrence in the neonatal intensive care un it (NICU), but the role of thrombopoietin (Tpo) in the pathophysiology is u nknown. We obtained serial plasma Tpo concentrations in 20 thrombocytopenic neonates in our NICU, and performed bone marrow studies in 15. The initial Tpo levels ranged from undetectable (<41pg/ml) to 1112 pg/ml and did not c orrelate with gestational age or platelet count. Neonates with decreased ma rrow megakaryocytes did not have plasma Tpo levels as high as those reporte d in adults, particularly in small for gestational age infants (Tpo < 300 p g/ml). In 14/15 neonates followed until resolution, the Tpo concentration d ecreased as the platelet count increased.