Fungal Exposure and Asthma: IgE and Non-IgE-Mediated Mechanisms

Abstract

Fungi are ubiquitous in indoor and outdoor environments and have been associated with respiratory disease including childhood and adult asthma. A growing body of evidence from human and animal studies has revealed a link between fungal exposure, especially indoor fungal exposure, with asthma initiation, persistence, and exacerbation. Despite the overwhelming evidence linking mold exposure and asthma, the mechanistic basis for the association has remained elusive. It is now clear that fungi need not be intact to impart negative health effects. Fungal components and fungal fragments are biologically active and contribute to asthma development and severity. Recent mechanistic studies have demonstrated that fungi are potent immunomodulators and have powerful effects on asthma independent of their potential to act as antigens. This paper will review the connection between fungal exposure and asthma with a focus on the immunological mechanisms underlying this relationship.

Modeling asthma: Pitfalls, promises, and the road ahead

“…1 Recent research has led to an understanding of asthma as a heterogeneous disease with multiple etiologies. The factors that initiate asthma and agents that elicit exacerbations are numerous and complex, and include infectious, environmental, allergic, and genetic components (reviewed in [2][3][4][5][6] ).…”

Short‐term effect of outdoor mould spore exposure on prescribed allergy medication sales in Central France

“…However, in the framework of the European Community Respiratory Health Survey, sensitization to Cladosporium was reported to be very low in the French population (less than 2%). Moreover, several biological factors have been proposed to support the role of mould exposure in respiratory health, involving allergic and irritative mechanisms . The drugs prescribed for rhinitis include oral and local antihistamines, used for allergic diseases, and local nasal corticosteroids, which are anti‐inflammatory drugs.…”

Bedroom Allergen Exposure Beyond House Dust Mites

“…The selection of commercially available fungal allergens remains limited, and fungal extracts are non-standardized [149, 153]. However, advances have been made in identifying species-specific and cross-reactive allergen components from different fungal sources, and in understanding immune responses to fungal antigens [4, 149, 154–158]. …”

“…Asthma, especially persistence and severity, has often been linked with sensitization to outdoor fungal species, such as Alternaria and Cladosporium [159], but an increasing body of literature supports the link between indoor fungal exposures and asthma [142, 158, 163, 164•, 165]. In numerous studies, residential fungal exposures have been associated with asthma exacerbations and severity [142, 158, 163, 164•, 166, 167].…”

“…In numerous studies, residential fungal exposures have been associated with asthma exacerbations and severity [142, 158, 163, 164•, 166, 167]. Although most of the asthma-related studies have been case-control studies or cross-sectional in nature, supporting data has also emerged from birth cohort studies [142, 158, 164•, 168–170]. In a recent study, asthma severity in atopic children was associated with fungal community composition, whereas in non-atopic children asthma severity was related to levels of total fungi, suggesting that effects of fungal exposures may differ by asthma subtypes [167].…”