Abstract:

Objective The purpose of this study was to detect methylation level of two sites（cg01623438， cg02744249）in Cathepsin Z gene（CTSZ）promoter and their correlation with asthma control and pulmonary func⁃ tion，and to detect the diagnostic value in adult asthma patients. Methods 30 asthma patients in our hospital were selected as asthma group，and they were divided into three groups according to Asthma Control Test Score. Mean⁃ while，30 healthy adults matched with gender and age were selected as control group. We detected the methylation levels of the two sites in nasal epithelium cells ，and the correlation analysis was performed between methylation level and lung function. Meanwhile，ROC curve analysis was used to show the asthma ⁃ predictive value. Results Both sites in asthma patients were hypomethylated，and the methylation level increased gradually in poorly controlled group，well controlled group and completely controlled group. The changes were also negatively related to the chang⁃ es of lung function. ROC curve analysis showed that，the AUC（area under the curve）of the site cg01623438 was 0.806（95%CI：0.683～0.896），the sensitivity was 100% and the specificity was 50%，P < 0.000 1；as the site g02744249，the AUC was 0.749（95%CI：0.620～0.852），the sensitivity was 43.3% and specificity was 100%（P = 0.000 1）；the combination of these two sites shows that the AUC was 0.827（95%CI：0.707～0.912），the sensitivity was 66.7% and specificity was 83.3%（P = 0.000 1）. Conclusion The methylation level of CTSZ promoter was significantly different in asthma patients，and it was related to asthma control and lung function. It can be used as an objective bio⁃marker to the assistance of asthma diagnosis and a reflection of the changes of lung function.

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