Fungi and allergic lower respiratory tract diseases: ABPA, ABPM, and SAFS

Asthma is a very common condition that affects 8% of adults and children, 25 million persons in the United States.

Epidemiologic studies have associated mold sensitivity with asthma - particularly Alternaria alternata and Cladosporium herbarum. Aspergillus fumigatus has been associated with severe persistent asthma in adults.

Allergic bronchopulmonary aspergillosis (ABPA)

Allergic bronchopulmonary aspergillosis (ABPA) is caused by A fumigatus and is characterized by:

- exacerbations of asthma
- recurrent transient chest radiographic infiltrates (on CXR or CT)
- coughing up thick mucus plugs
- peripheral and pulmonary eosinophilia
- increased total serum IgE and fungus-specific IgE levels, especially during exacerbation

The airways can be chronically or intermittently colonized by A. fumigatus.


Various fungi including Penicillium and Aspergillus spp. growing in axenic culture. Image source: Wikipedia, Dr. David Midgley Cultures: Dr. David Midgley University of Sydney, Australia, Creative Commons Attribution ShareAlike 2.5 License.

Allergic bronchopulmonary mycosis (ABPM)

ABPA is the most common form of allergic bronchopulmonary mycosis (ABPM) - other fungi, Candida, Penicillium, and Curvularia species, are also implicated.

The characteristics of ABPM include:

- severe asthma
- eosinophilia
- markedly increased total IgE and specific IgE levels
- bronchiectasis
- mold colonization of the airways

Severe asthma associated with fungal sensitization (SAFS)

Severe asthma associated with fungal sensitization (SAFS) describes the high rate of fungal sensitivity in patients with severe asthma and improvement with antifungal treatment.

The immunopathology of ABPA, ABPM, and SAFS is incompletely understood.

Treatment

Oral corticosteroid and antifungal therapies appear are partially successful in patients with ABPA.

References:

Fungi and allergic lower respiratory tract diseases. Knutsen AP, Bush RK, Demain JG, Denning DW, Dixit A, Fairs A, Greenberger PA, Kariuki B, Kita H, Kurup VP, Moss RB, Niven RM, Pashley CH, Slavin RG, Vijay HM, Wardlaw AJ. J Allergy Clin Immunol. 2012 Feb;129(2):280-91. Free full text is available from JACI.