ISSN 2997-1036
International Journal of Hematology | Vol. 4, No. 6, June 2013 | pp. 41–48
DOI: 10.46882/2013/IJH/000042
Original Article
Title: Evaluation of thrombopoietin receptor expression and reticulated platelets in chronic immune thrombocytopenia
Names of Authors: G. M. Babalola¹, I. N. Nwosu², K. S. Abubakar³
Authors’ Affiliations: ¹Department of Haematology and Blood Transfusion, Lagos University Teaching Hospital, Lagos, Nigeria; ²Department of Pathology, University of Nigeria, Nsukka, Nigeria; ³Department of Pathology, Bayero University, Kano, Nigeria
Abstract: Mechanisms driving thrombocytopenia in chronic immune thrombocytopenia include both accelerated platelet clearance and impaired megakaryocyte production. This study evaluated the relationship between surface thrombopoietin receptor (MPL) expression on platelets, plasma thrombopoietin levels, and the percentage of circulating reticulated platelets in 48 adult patients with chronic immune thrombocytopenia. Flow cytometry quantified thrombopoietin receptor density and thiazole orange-positive reticulated platelets, while plasma thrombopoietin was measured via enzyme-linked immunosorbent assay. Patients with immune thrombocytopenia exhibited an elevated mean percentage of reticulated platelets (14.6 ± 3.8%) compared to healthy controls (3.2 ± 0.9%, P < 0.001), reflecting increased bone marrow thrombopoietic activity. However, surface thrombopoietin receptor expression density on immune thrombocytopenia platelets was reduced by 52.4% relative to controls. Plasma thrombopoietin concentrations were only mildly elevated (mean 42.6 ± 12.4 pg/ml), which is inappropriately low for the degree of thrombocytopenia. The downregulation of surface thrombopoietin receptors combined with blunted plasma thrombopoietin responses highlights an underlying defect in megakaryocyte stimulation. These findings support using thrombopoietin receptor agonists to overcome relative bone marrow insufficiency in patients refractory to immunosuppressants.
Keywords: Immune thrombocytopenia, thrombopoietin receptor, reticulated platelets, megakaryopoiesis, flow cytometry
Manuscript Timeline: Received: March 08, 2013; Revised: April 14, 2013; Accepted: May 10, 2013; Published: June 19, 2013