[The study of atmospheric particulate matters and IFN-γDNA methylation in CD4⁺ T cells from patients with AR children]

Objective:To investigate the possible effects of meteorological and environmental factors on AR of children and IFN-γgene specific DNA methylation levels in CD4⁺ T cells of patients with AR. Method:Undergoing follow-up on 35 pediatric AR patients (6-12 years). Data on daily sulfur dioxide (SO₂), nitrogen dioxide (NO₂), particulate matter of diameter smaller than 10 micrometer (PM-10) and particulate matter of diameter smaller than 2.5 micrometer (PM2.5), the average of ozone (O₃) per 8 hours was available as average values derived from the data of 6 state controlled monitoring stations distributed across Pudong district, Shanghai. We quantified IFN-γ (interferon-γ) gene specific DNA methylation levels in CD4⁺ T cells from 35 patients with AR and 30 healthy controls. mRNA levels of IFN-γ gene were measured by real-time reverse transcriptase-PCR. Methods of personal exposure assessment of PM2.5 and PM10 were measured. Result:Compared with control, IFN-γ promoter region was hypermethylated in AR CD4⁺ T cells (P<0.05). Of all observed CpG sites in IFN-γ promoter region, there were significant differences in CpG⁻²⁹⁹, CpG⁺¹¹⁹, CpG⁺¹⁶⁸ (P=0.004, P=0.029, P=0.035). IFN-γ mRNA expression was significantly increase in CD4⁺ T cells (P<0.05). The level of IFN-γ mRNA expression was negatively correlated to mean level of methylation in IFN-γ promoter region. After adjusting, level of long exposure PM2.5 was positively correlated with level of methylation in IFN-γ promoter region. Conclusion:Level of methylation in IFN-γ promoter region may be affected by long exposure PM2.5.