Investigating the Level of MUC5B Expression in the Plasma of Patients with Idiopathic Pulmonary Fibrosis (IPF) Compared to Healthy Individuals

Introduction: Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease associated with high morbidity and mortality. Genetic factors, particularly the MUC5B promoter polymorphism, have been strongly implicated in disease pathogenesis. Given the shared embryological origin of the respiratory and oral epithelia, investigating systemic MUC5B expression may provide insights relevant to craniofacial and mucosal health. This study aimed to evaluate MUC5B gene expression in Iranian patients with IPF and compare the findings with healthy controls. Materials and Methods: A case–control study was conducted involving 15 IPF patients and 15 age-matched healthy individuals. Peripheral blood samples were collected, RNA was extracted, and MUC5B expression levels were quantified using quantitative real-time PCR (qRT-PCR) normalized to a housekeeping gene. Statistical analyses included ANOVA, the Least Significant Difference (LSD) test, and Spearman correlation. Results: MUC5B expression was detected in 80% of IPF patients compared to 40% of controls (P < 0.001). Relative expression analysis revealed that MUC5B mRNA levels were approximately 2.53-fold higher in the IPF group. No significant age difference was observed between groups. Conclusion: Elevated MUC5B expression is significantly associated with IPF, supporting its potential role as a genetic biomarker for disease susceptibility. The systemic nature of this dysregulation suggests it could also serve as a model for understanding mucin-related pathologies in the aerodigestive tract, including the oral cavity. Further studies with larger cohorts are warranted to confirm these findings and explore their clinical utility. Keywords: Idiopathic pulmonary fibrosis; Interstitial lung disease; Muc5b promoter polymorphism; Gene expression; Biomarker; Qrt-pcr; Iran; Genetic susceptibility; Pulmonary fibrosis pathogenesis; Mucin overexpression; Salivary mucins; Oral mucosa; Maxillofacial research; Aerodigestive tract.