Foxp3 methylation status in children with primary immune thrombocytopenia

Aim: To investigate the status of DNA methylation in the Foxp3 promoter in pediatric ITP patients and assess the role of DNA methylation of Treg cells in the pathogenesis of ITP. Methods: Quantitative DNA methylation levels of Foxp3 promoter in pediatric ITP patients were detected by MassARRAY EpiTYPER. Methylation levels of Foxp3 promoter were analyzed in ITP patients and normal controls. Results: Significantly higher expression of CpG-2. CpG-3 and CpG-11.12 was observed in ITP patients compared to the controls. A subgroup analysis revealed that persistent and chronic ITP patients exhibited significantly higher CpG-6 expression than in the subgroup of newly diagnosed ITP patients. All patients who represented newly diagnosed ITP at admission were reclassified at later follow-up. In this follow-up subgroup analysis, there were significantly higher levels of CpG-6 in the persistent ITP group than that in the newly diagnosed ITP group. Conclusions: Our results indicate that defective Treg cell activity identified in ITP might be partially mediated through hypermethylation of CpG sites in the promoter region of Foxp3. (C) 2014 Published by Elsevier Inc. on behalf of American Society for Histocompatibility and Immunogenetics.