[Expression and differential diagnostic value of serum microRNA for invasive pulmonary aspergillosis]

Objective: To explore the expression and the clinical diagnostic value of serum miR-21 for invasive pulmonary aspergillosis (IPA). Methods: Outpatients and inpatients from the Fourth Affiliated Hospital of Guangxi Medical University were included in the study during June 2014 to September 2015. The IPA group had 40 patients, male 22, female 18, aged 55-68 years (mean 60 ), while the control groups included 50 patients with pulmonary tuberculosis [male 23, female 27, aged 50-62 years (mean 55 )], 50 patients with lung cancer [male 30, female 20, aged 55-70 years (mean 62)], and 50 healthy controls [male 25, female 25, aged 50-67 years (mean 60) ]. Serum were obtained and the levels of miR-21 and galactomannan (GM test) and (1, 3)-beta-D-glucan (G test) were measured. The related indexes were analyzed by logistic regression and ROC curves. Results: The serum miR-21 expression in IPA and lung cancer patients were increased, the median values (P(25) and P(75)) being 0.42(0.31, 0.62)and 0.80(0.65, 0.94) respectively, both of which were significantly higher than those of the healthy controls [ 0.09(0.04, 0.15)] and the tuberculosis cases [ 0.08(0.03, 0.16)], P<0.001. The AUCs of miR-21 in IPA group, when compared to healthy controls, tuberculosis cases and lung cancer cases were 0.914, 0.897 and 0.863 respectively, with the Youden index being 0.780, 0.700 and 0.605 respectively. The serum levels of miR-21 in between 0.198 and 0.723 had preferable diagnostic accuracy. ROC analysis for miR-21 in IPA compared to healthy controls showed that the AUCs of miR-21 combined with G test or GM test were 0.992 and 0.966 respectively, the sensitivity being 95% (38/40) and 93% (37/40) respectively, the specificity being 98% (49/50) and 96% (48/50) respectively, and the Youden index being 0.930 and 0.885 respectively. If miR-21 was combined with G test and GM test, the AUC was 0.994, the sensitivity and the specificity being 98% (38/40) and 96% (48/50) respectively, and the Youden index increased to 0.935. ROC analysis for miR-21 in IPA compared to tuberculosis cases showed that when miR-21, G test and GM test were combined, the AUC was 0.984, the sensitivity and the specificity being 98% (38/40) and 90% (45/50) respectively, and the Youden index being 0.875. ROC analysis for miR-21 in IPA compared to lung cancer cases showed that the AUC for miR-21 with G test and miR-21 with GM test were 0.948 and 0.979 respectively, the Youden index being 0.725 and 0.895 respectively. When miR-21, G test and GM test were combined, the AUC was 0.998, the sensitivity and the specificity being 100% (40/40) and 98% (49/50) respectively, and the Youden index increased to 0.980. Conclusions: The serum level of miR-21 in IPA and lung cancer patients were significantly elevated. The serum level of miR-21 between 0.198 and 0.723 had preferable differential diagnostic accuracy, and therefore miR-21 may be regarded as an independent potential diagnostic serum marker of IPA. The diagnostic efficiency of miR-21 combined with G test and GM test may be more preferable, and remarkably increase the differential diagnosis of IPA from tuberculosis and lung cancer.