Granulocyte-macrophage colony-stimulating factor (GM-CSF) in children with acute immune thrombocytopenic purpura

Backround: The purpose of our study was to assess the serum level of GM-CSF in children with acute ITP and its correlation with clinical parameters and with the level of platelet-associated immunoglobulins. Material/Methods: Thirty children with acute ITP were selected from the inpatient department at Alexandria University Children's Hospital at El Shatby. Ten apparently healthy children served as controls. ITP Patients were divided according to platelet count into those with platelet count >20,000/ul and cases with platelet counts <20,000/ul. Serum GM-CSF was measured by the ELISA technique. Total IgG was measured by radial immunodiffusion plates, and PAIgG was detected directly by flow cytometry. Results: Total IgG showed significant elevation in ITP patients as compared to controls (t=2.748, P<0.05), but no correlation was detected between platelet antibodies and total IgG (r=-0.140, P=0.460). 86% of the patients had elevated platelet-associated immunoglobulin (PAIgG). No correlation between PAIgG and platelet count was detected (r=-0.072, P=0.72). Serum GM-CSF was significantly higher in ITP patients than controls (t=3.757, P<0.05). An inverse correlation was found between serum GM-CSF and platelet count (r=-0.4643, P=0.010). There was positive correlation between serum GM-CSF and PAIgG (r=0.4224, P=0.020). Conclusions: Our results suggest that GM-CSF may have a role in the pathogenesis of ITP through activation of the mononuclear phagocyte system, resulting in accelerated destruction and phagocytosis of antibody-coated platelets and decreased platelet count.