Epicoccum purpurascens
Summary
Epicoccum purpurascens (E. nigrum) is a ubiquitous mold of the Order Pleosporales, mostly found in plant materials and soil worldwide. It is mostly a saprophyte and shows a variety of phenotypes. The particles causing allergic reactions are airborne conidia (a type of spore).
Hypersensitivity pneumonitis (HP) and asthma are the main clinical presentations of E. purpurascens allergy. Cross reactivity with other molds, especially if taxonomically close, may occur.
Epidemiology
Worldwide distribution
Sensitization to Epicoccus purpurascens has been reported in 5–7% of people worldwide.
Risk factors
Being male was associated with poorer control of asthma symptoms in patients exposed to indoor molds, including E. purpurascens.
Route Of Exposure
Main
Inhalation of conidia.
Clinical Relevance
E. purpurascens (Epicoccum nigrum) was identified as the cause of hypersensitivity pneumonitis (HP) in two children, following exposure to a moldy basement.
E. nigrum can colonize the nasal and sinus cavities and cause allergic fungal sinusitis (AFS).
Asthma
Fungal sensitization exacerbates asthma; exposure to E. nigrum was associated with poorer control of asthma symptoms in male patients. Patients with life-threatening asthma needing admission to the intensive care unit or experiencing a respiratory arrest are significantly more likely to be sensitized to certain fungi, including E. purpurascens.
Diagnostics
Main methods
Personal volumetric petri plate sampler or a single stage Andersen air sampler.
The presence of allergen-specific antibodies is usually determined by skin prick tests (SPTs) and serology for IgE. SPT reactions to Epicoccum purpurascens allergens in patients with respiratory allergies varied in positivity, with 42% of patients showing mild to moderately positive reactions, 12% showing moderately positive reactions and 5.3% showing highly positive skin reactions. In the same study, the serum of SPT+ (positive) patients was tested by ELISA for the presence of IgE specific for the fungal antigens that caused the positive skin reactions. This showed 64.7% concordance for E. purpurascens antigens when comparing the skin-prick tests and the ELISA in vitro immunoassay.
Prevention And Therapy
Allergen immunotherapy
Immunotherapy is currently not recommended for patients allergic to molds, due to complexities of the allergens and patient co-allergies. However, a study carried out in mice showed that the enzymatic properties of the E. purpurascens allergenic antigen Epi p 1 (a serine protease) can elicit inflammation. The authors suggest that an enzymatically inactive Epi p 1 may be a candidate for immunotherapy.
Prevention strategies
Avoidance is difficult to achieve, due to the ubiquitous nature of E. purpurascens spores, especially in dry, windy periods.
Cross-Reactivity
Cross-reactivity has been demonstrated to other molds. A 33.5 kDa E. purpurascens allergen named Epi p 1 was recognized by rabbit antibodies specific for 5 other molds, namely Aspergillus fumigatus, Alternaria alternata, Cladosporium herbatum, Fusarium solani and Curvularia lunata. In another study, the serum of 10 patients diagnosed with allergic fungal sinusitis (AFS) was used to determine whether IgE specific to other fungi (including E. purpurascens) were present. All of the AFS patients showed a degree of cross reactivity to 6 other fungi.
In a large study of 668 serum samples from patients which who had previously recorded at least one IgE positivity to fungal antigens, associations were observed between the patterns of IgE sensitization and fungal phylogenetic relationships. Using a panel of 17 fungal extracts including E. purpurascens, some samples were only positive to one fungal species, whereas many were multi-sensitized. The results suggest that the associations are likely due to antigen cross-reactivity between fungal species, not uncommon in more closely related species.
References
- Mims CWMW, Richardson EARA. Ultrastructure of sporodochium and conidium development in the anamorphic fungus Epicoccum nigrum. Canadian Journal of Botany. 2005;83(10):1354-63.
- Andersen GL, Frisch AS, Kellogg CA, Levetin E, Lighthart B, Paterno D. Aeromicrobiology/air quality2009.
- Arenal F, Platas G, Martin J, Asensio FJ, Salazar O, Collado J, et al. Comparison of genotypic and phenotypic techniques for assessing the variability of the fungus Epicoccum nigrum. J Appl Microbiol. 2002;93(1):36-45.
- Weber RW. Outdoor Allergens. 2015. p. 185-.
- Kinsey G, Paterson R, Kelley J. Filamentous fungi in water systems. Handbook of Water and Wastewater Microbiology: Elsevier; 2003. p. 77-98.
- Agrios G. Control of Plant Diseases. 2005. p. 293-353.
- Lorenzini M, Zapparoli G. Occurrence and infection of Cladosporium, Fusarium, Epicoccum and Aureobasidium in withered rotten grapes during post-harvest dehydration. Antonie van Leeuwenhoek. 2015;108(5):1171-80.
- Kochar S, Ahlawat M, Dahiya P, Chaudhary D. Assessment of allergenicity to fungal allergens of Rohtak city, Haryana, India. Allergy Rhinol (Providence). 2014;5(2):56-65.
- Uniprot.org. Taxonomy - Epicoccum nigrum (Soil fungus) (Epicoccum purpurascens) 2021 [cited 2021 29.11.21]. Available from: https://www.uniprot.org/taxonomy/105696.
- Bisht V, Arora N, Singh BP, Gaur SN, Sridhara S. Purification and Characterization of a Major Cross-Reactive Allergen from <i>Epicoccum purpurascens</i>. International Archives of Allergy and Immunology. 2004;133(3):217-24.
- Segura-Medina P, Vargas MH, Aguilar-Romero JM, Arreola-Ramírez JL, Miguel-Reyes JL, Salas-Hernández J. Mold burden in house dust and its relationship with asthma control. Respir Med. 2019;150:74-80.
- Twaroch TE, Curin M, Valenta R, Swoboda I. Mold allergens in respiratory allergy: from structure to therapy. Allergy Asthma Immunol Res. 2015;7(3):205-20.
- Noble JA, Crow SA, Ahearn DG, Kuhn FA. Allergic fungal sinusitis in the southeastern USA: involvement of a new agent Epicoccum nigrum Ehrenb. ex Schlecht. 1824. J Med Vet Mycol. 1997;35(6):405-9.
- Hogan MB, Patterson R, Pore RS, Corder WT, Wilson NW. Basement shower hypersensitivity pneumonitis secondary to Epicoccum nigrum. Chest. 1996;110(3):854-6.
- Denning DW, Pashley C, Hartl D, Wardlaw A, Godet C, Del Giacco S, et al. Fungal allergy in asthma-state of the art and research needs. Clin Transl Allergy. 2014;4:14.
- Black PN, Udy AA, Brodie SM. Sensitivity to fungal allergens is a risk factor for life-threatening asthma. Allergy. 2000;55(5):501-4.
- Kukreja N, Sridhara S, Singh BP, Arora N. Effect of proteolytic activity of Epicoccum purpurascens major allergen, Epi p 1 in allergic inflammation. Clinical and experimental immunology. 2008;154(2):162-71.
- Kukreja N, Singh BP, Arora N, Gaur SN, Sridhara S. Identification of Epicoccum purpurascens allergens by two-dimensional immunoblotting and mass spectrometry. Immunobiology. 2008;213(1):65-73.
- Bisht V, Arora N, Singh BP, Pasha S, Gaur SN, Sridhara S. Epi p 1, an allergenic glycoprotein of Epicoccum purpurascens is a serine protease. FEMS Immunol Med Microbiol. 2004;42(2):205-11.
- Hutcheson PS, Schubert MS, Slavin RG. IgE immunoblot reactivity in allergic fungal sinusitis. Journal of Allergy and Clinical Immunology. 2005;115(2):S53.
- Soeria-Atmadja D, Onell A, Borgå A. IgE sensitization to fungi mirrors fungal phylogenetic systematics. J Allergy Clin Immunol. 2010;125(6):1379-86.e1.