Allergic fungal airway disease: pathophysiologic and diagnostic considerations

Area of Science:

• Medical Mycology
• Pulmonology
• Allergy and Immunology

Background:

• Fungal spores are common airborne allergens.
• Some fungi can cause both allergic and infectious lung responses.
• Thermotolerant fungi pose a risk for lung damage in sensitized individuals.

Purpose of the Study:

• To review biomarkers for diagnosing, predicting prognosis, and guiding treatment of allergic fungal airway disease (AFAD).
• To discuss current diagnostic criteria and propose a more inclusive term (AFAD) for fungal-associated lung disease.

Main Methods:

• Review of current literature on fungal spores, aeroallergens, and lung disease.
• Analysis of diagnostic biomarkers including specific IgEs, fungal culture, quantitative PCR, total IgE, hypereosinophilia, high attenuation mucus, and bronchiectasis.
• Discussion of clinical presentations and diagnostic criteria for fungal-associated lung disease.

Main Results:

• Current diagnostic biomarkers for AFAD, such as specific IgEs and fungal cultures, have limited sensitivity.
• Novel biomarkers like specific IgEs to fungal components and quantitative PCR may improve sensitivity.
• Non-specific markers like total IgE and hypereosinophilia do not correlate well with disease activity; high attenuation mucus and bronchiectasis are specific but insensitive markers.

Conclusions:

• The term allergic bronchopulmonary aspergillosis should be replaced with the more inclusive term allergic fungal airway disease (AFAD).
• Liberalized diagnostic criteria focusing on IgE sensitization to thermotolerant fungi are recommended.
• These criteria can help identify patients susceptible to developing lung damage from fungal exposure.