Fungi Sensitization in Spain: Importance of the Alternaria alternata Species and Its Major Allergen Alt a 1 in the Allergenicity

Abstract

Prevalence of allergy to fungi is around 3–10%. The most prevalent species involved in sensitizations are Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, and Penicillium notatum. Our main objective was to estimate the prevalence of fungal sensitization and its variation across Spain. Following the ICH-GCP, we recruited 1156 patients from 15 allergy departments in Spain. Hospitals were selected by bioclimatic areas. Patients underwent a skin prick test (SPT) with fungi, pollens, house dust mites, and animal dander. Specific IgE to Alternaria alternata and Alt a 1 was assessed in patients with positive SPT to fungi. Of the 233 patients (20.2%) sensitized to at least one of the five fungi tested, 162 (69.5%) were sensitized to Alternaria alternata and Alt a 1, of whom 113 (69.8%) were children; 181 (77.7%) were also polysensitized to other allergens. Alternaria alternata and Alt a 1 sensitization was present in 25.4% of patients in the Continental area, 12.0% in the Mediterranean area, 7.0% in the Semidesertic area, and 2.3% in the Oceanic area. Prevalence of sensitization to the other tested sources was 63.8% to pollens, 60.5% to house dust mite, and 38.1% to animal dander. We concluded that the prevalence of fungal allergy is increasing. Fungi are still the fourth source of allergen sensitization. Alternaria alternata sensitization is the most prevalent in allergic patients to fungi. Alt a 1 is present in almost 90% of the patients sensitized to Alternaria alternata.

Changes in the Sensitization Pattern to Alternaria alternata Allergens in Patients Treated with Alt a 1 Immunotherapy

“…In Europe, it is estimated to be between 4.4% [8] and 9% [9] of the general adult population, and, in the US, the prevalence rate is estimated to be as high as 12.9% [10]. Recently, our working group published that the prevalence of sensitization to A. alternata in Spanish allergic patients has reached 18.4% [11]; this is close to the 20% described previously [12].…”

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

“…However, in recent decades the application of molecular diagnostic procedures using individualized allergens has been decisive in the management of atopic individuals and allergic patients [ 18 ]. Described more than 20 years ago, it is known that the Alt a 1 allergen is the main allergen of A. alternata [ 19 , 20 , 21 ], with more than 80% of Alternaria allergic patients being sensitive to this allergen [ 3 , 22 , 23 ]. Since then, several other allergens belonging to this fungal species have been described ( Table 1 ).…”

“…Fungi are the fourth source of sensitization involved in allergic respiratory diseases preceded by pollens and dust mites. The exposure to allergenic molds can cause IgE-mediated allergic rhinitis, asthma and atopic dermatitis [ 3 ], and it has been described that the sensitization to some fungi such as Aspergillus and/or Alternaria is related to the severity of an asthmatic arrest [ 4 ].…”

“…There are several epidemiologic studies about fungal allergy prevalence, but the data vary according to the method of diagnosis [ 4 ]. It is estimated that the prevalence of allergies to molds is about 3–10%, although the prevalence of fungal sensitization shows a wide geographical variability [ 3 ]. Among the allergenic mold species, Alternaria alternata , Aspergillus fumigatus , Cladosporium herbarum and Penicillium notatum are the ones with the highest prevalence in allergic disease or sensitizations [ 5 ].…”

Airborne Alt a 1 Dynamic and Its Relationship With the Airborne Dynamics of <em>Alternaria</em> Conidia and Pleosporales Spores

“…Up to now, the exact prevalence of Alternaria allergens has not been established since reports of skin prick test (SPT) reactivity to this fungus range between 3 and 91%, depending upon the population studied, extracts used, and species tested [5,12,13]. In Spain, in a population of 1156 patients, 18.4% and 14.1% SPT resulted positive to Alternaria alternata and Alt a 1, respectively, and 92% suffered from allergic rhinitis [14]. The same authors showed results by regions and, in the study area (Catalonia), the percentage of positive IgE to A. alternata and Alt a 1 was 17,8% with children more affected than adults (7,7%).…”