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.