Nasal cell DNA methylation, inflammation, lung function and wheezing in children with asthma.

AIMS: DNA methylation is increasingly proposed as a mechanism for underlying asthma-related inflammation. However, epigenetic studies are constrained by uncertainties on whether samples that can be easily collected in human individuals can provide informative results.

METHODS

Two nasal cell DNA samples were collected on different days by nasal brushings from 35 asthmatic children aged between 8 and 11 years old. We correlated DNA methylation of IL-6, iNOS, Alu and LINE-1 with fractional exhaled nitric oxide, forced expiratory volume in 1 s and wheezing.

RESULTS

Fractional exhaled nitric oxide increased in association with lower promoter methylation of both IL-6 (+29.0%; p = 0.004) and iNOS (+41.0%; p = 0.002). Lower IL-6 methylation was nonsignificantly associated with wheezing during the week of the study (odds ratio = 2.3; p = 0.063).

CONCLUSION

Our findings support the use of nasal cell DNA for human epigenetic studies of asthma.