Research Article

The Immunopathogenesis of COVID-19 and Streptococcus pneumoniae Co-infection: A Focus on PMN-Driven Pro-inflammatory Cytokine Dynamics

Abstract

This study explored the immunopathological interplay between COVID-19 and Streptococcus pneumoniae co-infection by examining pro-inflammatory gene and protein expression in polymorphonuclear cells (PMNs). PMNs were isolated from healthy controls, COVID- 19-positive patients, and COVID-19 patients with S. pneumoniae co-infection. Quantitative real-time PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to quantify mRNA and protein levels of TNF-α, IFN-γ, and IL-6. Results revealed significant upregulation of TNF-α and IFN-γ mRNA and protein in both COVID-19 and co-infected groups (p<0.0001), indicating a robust pro inflammatory response. Notably, IL-6 mRNA was significantly elevated only in the COVID-19 group, suggesting a distinct role in viral, but not co-infection-associated, inflammation. These findings demonstrate that S. pneumoniae co-infection significantly modulates pro inflammatory responses in PMNs during COVID-19, with a specific focus on TNF-α and IFN-γ, highlighting the potential for exacerbated inflammation in co-infected individuals. This study underscores the importance of considering bacterial co-infections in COVID-19 management and warrants further investigation into targeted therapeutic interventions.