Background: The nasopharynx is a critical interface for the entry of respiratory pathogens, where the interaction between the host immune response and microbial load determines the clinical outcome of acute respiratory infections (ARI). Although the systemic response to ARI is well-documented, the local immune signatures and their correlation with different types of pathogens (viral, bacterial, or mixed) and the total microbial load in children remain to be fully elucidated. Understanding these local interactions is essential for identifying potential biomarkers of infection severity and type.
Abstract: Methods: A cross-sectional study was conducted with children (aged 6 months to 5 years) presenting with ARI at a hospital in Salvador, Brazil. Nasopharyngeal aspirates were collected to identify pathogens (viruses and bacteria) using molecular methods (RT-PCR and qPCR) and to quantify microbial load. Local immune signatures were assessed by measuring the expression of 20 cytokines and chemokines. Computational biology tools, including network analysis and principal component analysis, were used to integrate immunological and microbiological data.
Results: Distinct immune signatures were associated with different infection profiles. Viral infections were characterized by a robust Type I Interferon-driven response (notably CXCL10/IP-10), while bacterial presence was more closely linked to pro-inflammatory markers like IL-1β and IL-6. A high total microbial load was strongly correlated with an overall increase in the local inflammatory environment. Furthermore, specific clusters of cytokines were able to distinguish between single viral infections, bacterial colonization, and co-infections with high accuracy.
Conclusion: The nasopharyngeal immune environment in children with ARI is highly compartmentalized and reflects both the type of invading pathogen and the total microbial burden. The identification of these in situ signatures, particularly the prominence of CXCL10 in viral cases, provides insights into the local pathogenesis of ARI and suggests new targets for diagnostic and therapeutic monitoring.
Keywords: Acute respiratory infection; nasopharynx; cytokines; microbial load; children; immune signatures.
Clique aqui
- Data de Publicação: 09/11/2018
- Autores: Kiyoshi F. Fukutani1 , Cristiana M. Nascimento-Carvalho2,3, Maiara L. Bouzas2 , Juliana R. Oliveira2 , Aldina Barral1,2, Tim Dierckx4 , Ricardo Khouri1,2 , Helder I. Nakaya5 , Bruno B. Andrade1,6 , Johan Van Weyenbergh4 * † and Camila I. de Oliveira1,2 * †
