Type:
Whole Allergen
Whole Allergen
Whole Allergen
Stemphylium herbarum
m10
Pleosporaceae
herbarum
Inhalation
Stemphylium herbarum
Pleospora herbarum, Stemphylium botryosum, leaf blight of onion
XN4FM
(ICD-11 is currently under implementation by WHO and the ICD-11 codes displayed in the encyclopedia may not yet be available in all countries)
Stemphylium herbarum (Pleospora herbarum) is a ubiquitous mold of the order Pleosporales, mostly found in plant materials and soil worldwide. It is a well-known plant pathogen. The particles causing allergic reactions are spores found in the environment.
Stemphylium spp. may be involved in the development of asthma. Cross reactivity with other molds, especially if taxonomically close, may occur.
Stemphylium herbarum is a ubiquitous mold of the Family Pleosporaceae; it is the anamorph (asexual form) of the fungus Pleospora herbarum (teleomorph, the sexual form) (1). This mold is a known plant pathogen, causing disease in a variety of plants including onions, tomatoes, durum wheat, lentils and dates (2-6). This mold produces dark conidiophores and the conidia (a type of spore) are round or oval (7, 8).
Stemphylium spp. spores could be detected all year round, though a seasonal peak was recorded in late summer/autumn and early spring (9-11). Stemphylium spp. and Pleospora herbarum spores were detected in outdoor and indoor air samples of primary schools (12), and both in urban and rural areas (11). A separate study reported that Stemphylium was more prevalent in natural areas and high locations (13). Pleospora has also been identified as one of the airborne fungi genera inside biofuel wood chip storage sites (14).
Taxonomic tree of Stemphylium genus (2, 15) |
|
Domain |
Eukaryota |
Kingdom |
Fungi |
Phylum |
Ascomycota |
Subphylum |
Pezizomycotina |
Class |
Dothideomycetes |
Order |
Pleosporales |
Family |
Pleosporaceae |
Genus |
Stemphylium |
Pleospora herbarum is found as airborne spores, at approximately 1–2% of the total spores detected in air and dust samples (9, 11, 13). Stemphylium herbarum is able to release allergens from both germinated and ungerminated spores (16).
There is a lack of specific reports of allergic disease attributed to Stemphylium spp.; however, its involvement in developing symptoms of asthma has been hypothesized (17).
Being male and black ethnicity both appear to be risk factors for asthma and fungal sensitization (17).
Stemphylium herbarum has a worldwide distribution (2).
Inhalation (18).
Gravity-based petri plate method (12), Lanzoni and Burkard samplers (11).
An association between severe asthma and fungal sensitization was demonstrated in a study that included Stemphylium herbarum (17) Fungal extracts, including S. herbarum, have been found to be sensitizing agents in asthmatic children (19).
The presence of allergen-specific antibodies is usually determined by skin prick tests (SPTs) and serology for IgE (17-19). In a study of 307 asthmatic patients, 55.8% tested positive for S. herbarum-specific IgE (17). Stemphylium was among one of the most common agents of sensitization, with 86.6% positive reactions (20).
Immunotherapy is currently not recommended for patients allergic to molds, due to complexities of the allergens and patient co-allergies (18).
Avoidance is difficult to achieve (18) due to the range of environments in which Stemphylium spp. can be found (2).
S. botryosum produces a 17–18 kDa allergen (21, 22).
Cross-reactivity has been demonstrated to other molds. In a study carried out on 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 S. herbarum, 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 (23). In another study, scientists were able to amplify an Alt a 1 analogue by polymerase chain reaction (PCR) from Stemphylium spp. and one Pleospora herbarum isolate (24). A 17–18 kDa S. botryosum allergen reacted to rabbit IgE raised against the Alternaria alternata antigen Alt a 1 (21, 22).
Author: RubyDuke Communications
Reviewer: Dr. Christian Fischer
Last reviewed:January 2022