Allergic inflammation enhances bacterial sinusitis in mice

Area of Science:

• Immunology
• Microbiology
• Otolaryngology

Background:

• Allergic rhinitis is a suspected, though unproven, contributor to sinusitis development.
• Understanding the interplay between allergic rhinitis and bacterial sinus infections is crucial for effective treatment.

Purpose of the Study:

• To investigate if ongoing allergic rhinitis worsens Streptococcus pneumoniae acute sinus infections.
• To determine the impact of allergic inflammation on bacterial load and host response in sinusitis.

Main Methods:

• BALB/c mice were sensitized to ovalbumin to induce allergic rhinitis.
• Sinuses were infected with Streptococcus pneumoniae, with or without concurrent ovalbumin administration.
• Histological evaluation of sinus tissue was performed to assess inflammation and bacterial presence.

Main Results:

• Allergic mice exhibited significantly higher bacterial recovery and increased inflammation (neutrophils, eosinophils, mononuclear cells) in sinus tissues compared to controls.
• Ongoing nasal allergic inflammation augmented Streptococcus pneumoniae infection and associated inflammatory responses.
• Increased neutrophil clusters were observed in the sinus mucosa of allergic mice post-infection.

Conclusions:

• Localized allergic responses in mice can augment bacterial sinus infections.
• Allergic sensitization alone, allergen exposure alone, or distal allergic responses do not enhance sinus infections.
• These findings underscore the role of local allergic inflammation in exacerbating bacterial sinusitis.