Fungal Allergen and Mold Allergy Diagnosis: Role and Relevance of Alternaria alternata Alt a 1 Protein Family

Abstract

Alternaria is a genus of worldwide fungi found in different habitats such as soil, the atmosphere, plants or indoor environments. Alternaria species are saprobic—largely involved in the decomposition of organic material—but they can also act as animal pathogens, causing disease in humans and animals, developing infections, toxicosis and allergic diseases. A. alternata is considered one of the most important sources of fungal allergens worldwide and it is associated with severe asthma and respiratory status. Among the A. alternata allergens, Alt a 1 is the main sensitizing allergen and its usefulness in diagnosis and immunotherapy has been demonstrated. Alt a 1 seems to define a protein family that can be used to identify related pathogenic fungi in plants and fruits, and to establish taxonomic relationships between the different fungal divisions.

Seasonal variation of airborne fungal diversity and community structure in urban outdoor environments in Tianjin, China

“…This fungal species has been primarily associated with the development of immunoglobulin E (IgE)-mediated respiratory illnesses ( Gabriel et al, 2016 ; Quesada, 2022 ). Clinically, A. alternata has been linked to asthma ( Bush and Prochnau, 2004 ; Pulimood et al, 2007 ; Mohammad and Khalil, 2022 ), allergic rhinosinusitis ( Schell, 2000 ; Sanchez et al, 2022 ), hypersensitivity pneumonitis ( Ogawa et al, 1997 ), oculomycosis ( Ozbek et al, 2006 ), onychomycosis ( Romano et al, 2001 ), skin infections ( Mayser et al, 2002 ), and Allergic Bronchopulmonary Mycosis (ABPM; Singh and Denning, 2012 ; Chowdhary et al, 2012 ).…”

“…The genera Alternaria, Aspergillus, Cladosporium , and Penicillium are the most common allergenic fungal taxa ( Shelton et al, 2002 ; Adhikari et al, 2004 ; Fang et al, 2005 ; Abdel Hameed et al, 2009 ). Alternaria is considered one of the dominant sources of aeroallergens, being responsible for allergic rhinitis ( Mokhtari Amirmajdi et al, 2011 ), and important risk factor for developing Asthma ( Salo et al, 2006 ; Lehmann et al, 2016 ; Hayes et al, 2018 ; Hernandez-Ramirez et al, 2021 ; Sanchez et al, 2022 ). Aspergillus fungi are ubiquitous saprotrophs, with about 20 species known to cause human diseases ( Dagenais and Keller, 2009 ).…”

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“…The type species A. alternata is currently considered to be a cosmopolitan species having saprobic and pathogenic lifestyles, with a wide host range such as soil, plants, or indoor environments (Woudenberg et al 2013, Armitage et al 2015, Lawrence et al 2016, Armitage et al 2020. According to a recent study based on morphology and phylogeny, Alternaria contains many species with conidial succession, including plant, human and post-harvest pathogens (Sánchez et al 2022). Most of the Alternaria species are saprobic and endophytic within various parts of crops including leaves, seeds, and fruits (Thomma et al 2003, Sánchez et al 2022.…”

“…According to a recent study based on morphology and phylogeny, Alternaria contains many species with conidial succession, including plant, human and post-harvest pathogens (Sánchez et al 2022). Most of the Alternaria species are saprobic and endophytic within various parts of crops including leaves, seeds, and fruits (Thomma et al 2003, Sánchez et al 2022. Rarely, they cause infections in humans and animals to develop toxicosis and allergic diseases (Woudenberg et al 2015, Lawrence et al 2016, Sánchez et al 2022.…”

Special Issue: Alternaria alternata: Should We Still Consider This Fungus as a Minor Brother in the Etiology of Respiratory Allergy?

“…Sánchez and colleagues [ 15 ] review the data supporting Alt a 1 as a phylogenetic marker, as a protein only belonging to Pleosporaceae species and the proposal of this allergen as a key tool for the diagnosis and immunotherapy of fungal allergy in European countries.…”