Micro RNA expression and asthma predisposition among children with recurrent infections

Objective: Asthma is a chronic disease characterized by impaired respiratory function. Primary immunodeficiencies are significant causes of morbidity and mortality. This study aimed to evaluate the presence of underlying immunodeficiency and predisposition to allergic asthma in children with frequent infections, and to assess the potential role of specific miRNAs as biomarkers. Materials and Methods: Between November 2024 and November 2025, 30 children aged 1–18 years with recurrent infections and 30 healthy controls who presented to Gaziantep University Şahinbey Research and Training Hospital were included. Serum samples were analyzed for four miRNAs (miRNA-146a, miRNA-155, miRNA-365, miRNA-375). Demographic, clinical, and laboratory data were prospectively evaluated. Results: The patient group showed significantly higher IgE levels and wheezing prevalence. A history of primary immunodeficiency was also more frequent. Children with wheezing had eosinophilia, and those with frequent hospitalizations exhibited lower CD19 levels. CD3/8 and CD16/56 levels were significantly reduced in children breastfed for less than 6 months. The post-bronchodilator FEV₁ change was greater in patients. miRNA-155 expression was significantly elevated, while children with low CD3/8 levels showed increased miRNA-375 expression. Elevated miRNA-155 and miRNA-375 were also observed in cases with rhinitis, eczema, or recurrent skin infections. Conclusion: Although frequent infections may suggest immune dysregulation, the findings are insufficient to confirm a clear predisposition to asthma. Broader, multi-centered studies investigating novel biomarkers are needed. Keywords: Frequent infections, Atopy, Allergy, Immunodeficiency, miRNA.