AUTHOR=Buendía Jefferson Antonio , Lindarte Erika Fernanda , Polack Fernando P. TITLE=TLR4 Gene Polymorphisms Interaction With Ascaris Infection in Severe RSV Bronchiolitis JOURNAL=Frontiers in Pediatrics VOLUME=Volume 10 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2022.876882 DOI=10.3389/fped.2022.876882 ISSN=2296-2360 ABSTRACT=Introduction : The identification of gene-environment interactions allows the recognition of groups with higher risk of morbidity. This study evaluated the interaction between the presence of TLR4 gene polymorphisms and Ascaris infection with severe bronchiolitis in a tropical Colombian region. Methods: We included all infants younger than 24 months hospitalized due to bronchiolitis in Hospital centers in the county of Rionegro, Colombia. To identify interaction between severe bronchiolitis and presence of TLR4 polymorphisms and Ascaris infection, we used log-binomial regression. Results: 417 infants were hospitalized due to bronchiolitis, of which 115 (27%) had severe bronchiolitis. In infants with RSV acute infection and positive anti-Ascaris IgE, TLR4 Asp299Gly was associated to low risk of severe bronchiolitis (OR 0.09, CI 95% 0.01-0.48). Conversely, in infants RSV negative with negative anti-Ascaris IgE, TLR4 Asp299Gly was associated with an increased risk of severe bronchiolitis (OR 14.5, CI 95% 2.2-96). Conclusion: The association between severe bronchiolitis and Ascaris infection in infants under 2 years old is mediated by TRL4 genotype.