慢性鼻窦炎伴鼻息肉中IL4基因异常甲基化与嗜酸性粒细胞浸润机制研究

The methylation of IL4 gene and eosinophil infiltration in chronic rhinosinusitis with nasal polyps

目的探究IL4基因异常甲基化与嗜酸性粒细胞浸润的机制。方法选取符合慢性鼻窦炎伴鼻息肉诊断标准的9例患者标本,根据鼻息肉组织病理嗜酸性粒细胞(Eos)浸润程度,分为嗜酸粒细胞性慢性鼻窦炎伴鼻息肉(eosinophilic chronic rhinosinusitis with nasal polyps,ECRSwNP)和非嗜酸粒细胞性慢性鼻窦炎伴鼻息肉(non-ECRSwNP,NECRSwNP)两组,比较两组样本不同炎症细胞计数差异。设计DNA甲基化引物,MassARRAY法进行IL4基因CpG位点DNA甲基化检测。运用线性拟合回归探究Eos计数和IL4基因CpG位点甲基化程度之间的线性关系。结果ECRSwNP组Eos计数高于NECRSwNP组(P=0.0043),其他炎症细胞数目相比无统计学差异。DNA甲基化检测显示,ECRSwNP组CpG位点5(CpG-5)的甲基化率显著低于NECRSwNP组(P=0.0311)。我们还发现IL4基因CpG-5甲基化率和组织Eos浸润有着较强的负相关关系(R2=0.53,P=0.0261)。通过回归模型拟合得到Eos=496.25-5.13×CpG-5(DNA甲基化率),结果表明随着IL4基因CpG-5甲基化水平的降低,鼻息肉中Eos浸润增加。结论IL4基因异常甲基化状态与Eos浸润程度相关,为CRSwNP发病机制提供表观遗传学证据。

OBJECTIVE To investigate the methylation of IL4 gene and eosinophil(Eos)infiltration.METHODS Nine patients who met the diagnostic criteria of chronic rhinosinusitis with nasal polyps(CRSwNP)were enrolled and divided into two groups:eosinophil type(ECRSwNP)and non-eosinophil type(NECRSwNP)according to Eos infiltration in nasal polyp.The differences in inflammatory cell counts in two groups were analysed.DNA methylation primers were designed,and DNA methylation at CpG site of IL4 gene was detected by MassARRAY.Linear fitting regression was used to explore the linear relationship between Eos count and the methylation ratio of IL4 gene CpG sites.RESULTS The number of Eos in the ECRSwNP group was significantly higher than that of NECRSwNP group(P=0.0043),and there was no significant difference in other type of inflammatory cells.DNA methylation detection showed that the methylation ratio of CpG site 5(CpG-5)in ECRSwNP group was significantly lower than that of NECRSwNP group(P=0.0311).We also found a strong negative correlation between the methylation ratio of IL4 gene CpG-5 and Eos infiltration(R~2=0.53,P=0.0261).Regression model predict:Eos=496.25-5.13×CpG-5(DNA methylation ratio).The results showed that the infiltration of Eos in nasal polyp increased while the methylation level of CpG-5 of IL4 gene decreased.CONCLUSION The abnormal methylation of IL4gene is related to Eos infiltration,which provides epigenetics evidence for the pathogenesis of CRS.