Thrombopoietin serum concentration in patients with reactive and myeloproliferative thrombocytosis

Abstract

We wished to test whether thrombopoietin (TPO) is entirely regulated by receptor binding or if other factors may play a role in the mechanism of TPO regulation. Therefore, we analyzed the TPO serum levels in 43 patients with reactive (secondary) thrombocytosis and in 37 with myeloproliferative thrombocytosis. Thrombocytosis was defined as a platelet level greater than 440 x 10(9)/l. Forty-two patients (98%) with reactive thrombocytosis had high concentrations of IL-6 correlating with elevated C-reactive protein levels. Twenty-three patients (53%) in this group had TPO serum concentrations of more than 300 pg/ml (normal: below 300 pg/ml). Only nine patients (24%) with myeloproliferative thrombocytosis had TPO serum levels above normal range, whereas 28 patients (76%) had normal levels of TPO. No correlation between the TPO serum levels and the concentrations of IL-6 or EPO was established. The other investigated thrombopoietic cytokines (IL-3, IL-11, GM-CSF) were unmeasurable; therefore, a correlation could not be assessed. We conclude that TPO concentrations are not strictly inversely related to platelet count. TPO serum levels are elevated especially in a considerable percentage of patients with reactive thrombocytosis, arguing for the existence of additional mechanisms of TPO regulation.

High platelet count associated with venous thromboembolism in cancer patients: results from the Vienna Cancer and Thrombosis Study (CATS)

“…Several studies have focused on the role of cytokines involvement in tumor-associated thrombocytosis [10][11][12][13][14][15]. However, it is still under discussion as to what extent thrombopoietin (TPO) secretion regulates the platelet count (PC) in cancer patients.…”

The molecular and cellular biology of thrombopoietin: the primary regulator of platelet production

“…Although TPO production does not appear to be altered in the liver in response to alterations in platelet counts, it is less certain whether altered production of the hormone is responsible for the thrombocytosis seen in in¯ammatory conditions. It is clear that platelet counts rise in response to in¯ammation (Griesshammer et al, 1999), and with the development of reliable immunoassays of TPO, 50 ± 500% increases in blood TPO concentrations have been found in thrombocytotic post-surgical patients and in individuals with Crohn's disease and other in¯ammatory conditions (Cerutti et al, 1997;Uppenkamp et al, 1998;. Thus, the regulation of TPO production and levels may be rather complex.…”

Characteristic Changes in Platelet-Large Cell Ratio, Lactate Dehydrogenase and C-Reactive Protein in Thrombocytosis-Related Diseases

“…However, EPO levels were not significantly different between patients with CML, ET and PV [19], and TPO levels were not significantly different between patients with ET and PV [20], although TPO and EPO levels were higher in patients with RT than with CMPD (CML, ET and PV).…”