IgE sensitization to fungi mirrors fungal phylogenetic systematics.
BACKGROUND
Fungal allergy is an elusive disease, and little progress has been made in this field during recent years. Moreover, because of the complexity of the organisms, it is difficult to categorize fungi systematically on the basis of morphologic characterization. However, recent molecular phylogenetics studies have substantially improved fungal categorization. In parallel, new approaches to analyze large IgE antibody datasets enable identification and visualization of IgE sensitization patterns.


OBJECTIVE
To study whether molecular phylogenetic relationships of fungal species, commonly used in allergy diagnosis, also are reflected in IgE sensitization profiles of individuals sensitized to fungi.


METHODS
A dataset was compiled of recorded serum IgE antibody levels to 17 different fungal species from 668 individuals sensitized to at least 1 of the 17 species. By applying a clustering method to this dataset, the fungal species were grouped into a hierarchical organization. Finally, the resulting organization was compared with recently published fungal systematics.


RESULTS
The hierarchical structure of fungi, based on the presence of IgE antibodies in sensitized individuals, very well reflected phylogenetic relationships. Examples include the distinct separation of basal fungi from the subkingdom Dikarya as well as individual cluster formations of fungi belonging to the subphylum Saccharomycotina and order Pleosporales.


CONCLUSIONS
To our knowledge, this is the first in-depth study that demonstrates a close relationship between molecular fungal systematics and IgE sensitization to fungal species. Because close evolutionary organisms typically have a higher degree of protein similarity, IgE cross-reactivity is likely the main reason for obtained organization.
Soeria-Atmadja
Daniel
D
Department of Medical Sciences, Uppsala University, Uppsala, Sweden. daniel.soeria-atmadja@medsci.uu.se
Onell
Annica
A
Borgå
Ase
A
D000485:Allergens / Q000276:immunology; D000908:Antibodies, Fungal / Q000145:classification / Q000235:genetics* / Q000276:immunology; D000946:Antigens, Fungal / Q000276:immunology; D005658:Fungi / Q000145:classification / Q000235:genetics* / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000382:microbiology*; D007114:Immunization; D007073:Immunoglobulin E / Q000145:classification / Q000235:genetics* / Q000276:immunology; D005810:Multigene Family; D010802:Phylogeny; D013045:Species Specificity; D040681:Structural Homology, Protein
D000485:Allergens; D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D007073:Immunoglobulin E