Granulomatosis with polyangiitis (GPA) is a rare autoimmune disease belonging to vasculitides that are pathogenetically related to anti-neutrophil cytoplasmic antibodies (ANCA). GPA often manifests in the upper respiratory tract, particularly in the sinonasal mucosa. Sinonasal biopsies can contribute significantly to correct diagnosis of GPA. However, biopsies frequently lack characteristic histological features and exhibit only nonspecific inflammation complicating early diagnosis of GPA. Epigenetic mechanisms, particularly microRNAs (miRNAs) have been increasingly implicated in the pathogenesis of autoimmune diseases and miRNAs seem promising as biomarkers for autoimmune diseases including GPA. In our study, we analyzed miRNA expression in sinonasal biopsy samples of patients with GPA and investigated if miRNA expression in sinonasal biopsies can contribute to early diagnosis of GPA.
The study included 37 sinonasal biopsy tissue samples from patients with GPA, 15 samples of sinonasal mucosa from patients with inflammation of other etiology, and 14 samples of sinonasal mucosa from control patient group without significant histopathological changes in the sinonasal mucosa. Among the GPA patients, 20 exibited histopathological features characteristic of GPA, while 17 had non-specific histological findings. Histological assesment was performed using standard histopathological techniques, while miRNA expression analysis was conducted using a miRCURY LNA miRNA miRNOME Human PCR Panel I+II and quantitative real-time PCR (qPCR).
Through miRNA expession profiling in sinonasal mucosal tissue samples, we identified 306 miRNAs that showed differential expression patterns between individual patient subgroups. Based on these results, we selected 11 miRNAs (miR-1-3p, miR-31-3p, miR-155-5p, miR-183-5p, miR-21-3p, miR-106a-5p, miR-190b-5p, miR-1248, let-7b-5p, miR-93-5p, and miR-182-5p) for further validation using qPCR, as expression profiles of these miRNAs demonstrated statistically significant differences among the analyzed patient groups.
Our study identified distinct miRNA expression patterns associated with GPA, which correlated with clinical and histopathological parameters, established in the study. Identified miRNAs represent promising diagnostic biomarkers that may improve the accuracy and early diagnosis of GPA in sinonasal mucosal tissues, particularly in patients in the early stages of the disease or those presenting with atypical clinical and/or histological features.
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