Abstract
BACKGROUND: Bronchiolitis is the most common lower respiratory tract infection, with the most commonly isolated organism being respiratory syncytial virus (RSV). Despite several studies on intestinal permeability in various acute and chronic pulmonary diseases, studies examining these molecules in patients diagnosed with bronchiolitis are very limited. This study was conducted to examine zonulin and claudin-3 levels to evaluate intestinal permeability in children diagnosed with bronchiolitis. MATERIALS AND METHODS: A total of 98 children, 60 patients with bronchiolitis and 38 healthy controls were included in this study. After informed consent of patients and their parents were obtained, 5 mL of blood serum samples were collected upon admission, after confirmation of the diagnosis, which were kept frozen until being analyzed for zonulin and claudin-3 levels and subsequently analyzed and compared between the groups. RESULTS: The median value of zonulin was 18.57 ng/mL in the patient group and 12.41 ng/mL in the control group. There was no significant difference in zonulin levels between the patient and control groups (p = 0.540). The mean claudin-3 (CLDN3) level was significantly lower in the patient group (3889.56) than the control group 4216.77 (p < 0.001). In the patient group, zonulin and claudin levels did not significantly differ by the need of mechanical ventilation and ICU administration (p > 0.05). CONCLUSION: In conclusion, CLDN3 levels were found to be significantly lower in patients with bronchiolitis than in the control group. This finding may indicate that low CLDN3 levels may be involved in pathogenesis of bronchiolitis, by impairing airway permeability Further studies with larger number of participants, investigating the effect of airway permeability on the pathogenesis of bronchiolitis, which compare zonulin and CLDN3 levels according to disease severity, are warranted.