Comparative study of serum inflammatory mediators and immunoglobulin levels in children with severe asthma infected by viruses versus bacteria.

BACKGROUND: By tracking fluctuations in inflammatory mediators and immunoglobulins (Igs) in bacterialversus viral-induced severe asthma (SA) cases, this research seeks to identify microbial-specific immune characteristics to guide individualized treatment. METHODS: This analysis included 100 children hospitalized between March 2023 and April 2025 for severe acute SA exacerbations with confirmed single-pathogen infections (50 viral vs. 50 bacterial). Serum samples collected preand post-treatment were analyzed for inflammatory mediators (Th1/Th2/Th17 cytokines and TNF-a) and Ig profiles (total IgE and IgG subclasses). Comparative analysis was performed to identify intergroup differences. RESULTS: At baseline, the viral group showed higher Th1/Th17 co-activation responses, whereas the bacterial group had elevated Th2 cytokines/TNF-a (P < 0.05). Therapeutic intervention reduced all cytokine subsets, though Th1/Th17 co-activation suppression was more marked in the viral group (P< 0.05), and Th2 decay lagged in the bacterial group. Besides, viral cases had elevated IgG1/IgG3; bacterial cases showed higher IgG2 (P< 0.05). After treatment, the levels of IgG1 and IgG3 in the virus group continued to increase, but IgG2 did not change. CONCLUSIONS: Viral SA infections predominantly trigger Th1/Th17 co-activation-mediated inflammation and higher IgG1/IgG3. In contrast, bacterial infections favor a Th2-dominant profile with IgG2 elevation, resulting in slower inflammation resolution.