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Hemoglobin‐bound platelets correlate with the increased platelet activity in hemoglobin E/β‐thalassemia
Author(s) -
Chamchoi Attaphon,
Srihirun Sirada,
Paiboonsukwong Kittiphong,
Sriwantana Thanaporn,
Kongkaew Peerawich,
Fucharoen Suthat,
Pattanapanyasat Kovit,
Sibmooh Nathawut
Publication year - 2020
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/ijlh.13260
Subject(s) - platelet , medicine , hemoglobin e , hemoglobin , chemistry , flow cytometry , endocrinology , thalassemia , platelet activation , adenosine diphosphate , immunology , platelet aggregation
An increase in platelet activity is a contributing factor to vascular complications in hemoglobin E/β‐thalassemia (HbE/β‐thal). Plasma‐free hemoglobin (Hb) increases in HbE/β‐thal patients and correlates with platelet activation, but the levels of Hb‐bound platelets have never been reported. In this study, we aimed to investigate the levels of Hb‐bound platelets and its association with platelet activity in HbE/β‐thal patients. Methods Hb‐bound platelets were measured by flow cytometry in 22 healthy subjects and 26 HbE/β‐thal patients (16 nonsplenectomized and 10 splenectomized HbE/β‐thal patients). Plasma Hb was measured by the chemiluminescence method based on the consumption of nitric oxide (NO) by Hb. Expression of P‐selectin and activated glycoprotein (aGP) IIb/IIIa on platelets was measured by flow cytometry as a marker of platelet activity. Results Both nonsplenectomized and splenectomized HbE/β‐thal patients had higher levels of Hb‐bound platelets and plasma Hb than healthy subjects. In vitro incubation of dialyzed Hb from patients with platelets of healthy subjects caused an increase in Hb‐bound platelets, which was partially inhibited by anti‐GPIbα antibody. Plasma Hb positively correlated with Hb‐bound platelets. Platelet P‐selectin expression at baseline and in response to adenosine diphosphate (ADP, 1 µM) stimulation was higher in nonsplenectomized and splenectomized HbE/β‐thal patients than healthy subjects. The ADP‐induced aGPIIb/IIIa expression on platelets was also higher in HbE/β‐thal patients than healthy subjects. Hb‐bound platelets correlated with baseline P‐selectin expression and ADP‐induced P‐selectin expression. Conclusion HbE/β‐thal patients have increased Hb‐bound platelets, which is associated with increased baseline platelet activation and reactivity.