Platelet Antibodies, Activated Platelets and Serum Leptin in Childhood Immune Thrombocytopenic Purpura

Abstract

Background/Aim: The aim of this study was to evaluate the levels of platelet-associated antibodies (PAIgG and PAIgM), activated platelets and serum leptin in children with acute immune thrombocytopenic purpura (ITP). Methods: The study included 40 patients with ITP and 40 healthy age- and sex-matched controls. PAIgG, PAIgM and activated platelet levels were estimated by flow cytometry, and serum leptin levels were estimated by ELISA. Results: Activated platelets and serum leptin were significantly higher in the ITP patients than in the controls. The percentage and mean florescence intensity of PAIgG and PAIgM staining were significantly higher in the patients than in the controls. Serum leptin and activated platelet levels in patients with thrombocytopenia of brief duration were significantly lower than those in patients with thrombocytopenia of prolonged duration. The levels of activated platelets, serum leptin and PAIgG were positively correlated, and the levels of serum leptin, activated platelets and platelet counts were negatively correlated. Conclusion: The increased levels of activated platelets, serum leptin and platelet-associated antibodies in children with acute ITP suggest that these factors could play a role in ITP pathogenesis. Additionally, activated platelets and serum leptin could have prognostic significance in paediatric acute ITP.

Flow cytometric measurement of platelet‐associated immunoglobulin in children with newly diagnosed Immune Thrombocytopenia

“…Badrawy et al . in a controlled study of 40 children with ITP found increased percentages of both IgG‐ and IgM‐positive platelets, with the highest IgG percentages in children with prolonged duration and the highest IgM percentages in those with brief duration. The selection of patients, technical details and the presentation of results in these studies make comparison with our findings difficult.…”

“…This finding suggests that elevation of PAIG causes some degree of platelet dysfunction from blocking of functional surface antigens. Levels of free CD‐antigens are reduced on antibody‐coated platelets , and the number of GP IIb/IIIa binding sites are lower in patients with ITP than in healthy controls . PAIgG and PAIgM possibly block functional GP IIb/IIIa receptors on the platelet surface, but the relationship between PAIG and platelet dysfunction in ITP has not yet been investigated .…”

“…A version permitting quantitation of PAIG using calibration with fluorescent immunobeads has been developed . Most clinical studies have investigated adults with ITP, but a few concerning children have been reported . FCM may also simplify measurement of platelet‐specific autoantibodies, as shown in a recently described immunobead assay .…”

The Role of Leptin in Childhood Immune Thrombocytopenia (ITP): An Anti-Inflammatory Agent?

“…As such, immune cell-derived leptin could act as an autocrine and/or paracrine signal that can enhance the action of leptin through the leptin receptor expressed on immune cells. Elevated levels of circulating leptin have also been associated with acute infections [ 24 ] and certain autoimmune diseases, including immune thrombocytopenia (ITP) [ 25 , 26 , 27 , 28 ]. It has previously been suggested that leptin plays an important role in the pathogenesis of ITP, and it has been proposed as a potential treatment target [ 26 , 27 , 28 ].…”

“…Elevated levels of circulating leptin have also been associated with acute infections [ 24 ] and certain autoimmune diseases, including immune thrombocytopenia (ITP) [ 25 , 26 , 27 , 28 ]. It has previously been suggested that leptin plays an important role in the pathogenesis of ITP, and it has been proposed as a potential treatment target [ 26 , 27 , 28 ].…”