Abstract: Objective: DNA methylation had been researched in many autoimmune diseases. Immune thrombocytopenia (ITP) is an organ-specific autoimmune disorder characterized by accelerated platelet destruction and bleeding symptoms. DNA methylation negatively regulates the gene expression. The aim of the current study was to investigate the relationship between the transcription levels of the IFN-γ and IL-4 and the methylation status of those gene promoters in ITP patients. Methods: The mRNA expression levels and DNA methylation of the IFN-γ and IL-4 were detected by the real-time quantitative PCR and bisulfite genomic sequencing, respectively. The relationship between CpG methylation and the mRNA levels of those genes were determined. Results: When compared with the healthy controls, the IFN-γ mRNA levels of ITP patients were significantly higher (1.86±0.29 vs 0.83±0.14, P<0.05). The levels of IL-4 mRNA transcripts were notably lower in ITP patients (0.78±0.22 vs 1.45±0.40, P<0.05). Most importantly, the Th1/Th2 (IFN-γ/IL-4) was remarkably higher in ITP patients than that of the controls (7.11±0.60 vs 3.12±1.88, p<0.01). There were no closely relationship between the mRNA levels of IFN-γ and IL-4 genes and the methylation status of those gene promoters. Conclusion: The ITP patients were in the Th1 polarization. The mRNA expression of IFN-γ and IL-4 were not associated with the DNA methylation status of those genes in ITP patients, indicating that the IFN-γ and IL-4 mRNA were not controlled by the DNA methylation of those genes.

Key words: thrombocytopenia autoimmune diseases interferon type iiinterleukin-4 RNA, messenger DNA methylation gene expression, DNA甲基化