Background: Although dysbiosis and the role of the microbiome in the pathogenesis
of inflammatory skin diseases have been intensively investigated, fungal colonization
or infection has received minimal attention.
Aims: To isolate and identify different fungal species namely Candida, Dermatophytes,
Malassezia, and Aspergillus from plaque psoriasis patients, evaluate the association
of IL-17A
gene single nucleotide polymorphisms (SNPs) with psoriasis, and to reveal
the relation between IL-17A
gene SNPs and the fungal presence within the psoriatic
plaques.
Patients/Methods: Fifty plaque psoriasis patients and fifty healthy age and sex volunteers
as controls were enrolled in this study. From psoriatic plaques, mycological isolation
was done by direct microscopic examination (10% KOH mount), culture onto the
three sets of media then species identification by phenotypic procedures. Genomic
DNA extraction and genotyping for IL-17A
(rs10484879) SNPs using polymerase
chain reaction and restriction fragment length polymorphism were also done.
Results: Psoriasis cases showed higher frequency of fungal growth 86% vs. 14% in controls;
(p < 0.001). The frequency of IL-17A
GA, AA, and total polymorphism (GA+AA)
genotypes in psoriasis cases was significantly higher than in controls. There was non-significant
association between different IL-17A
genotypes and fungal growth except
Aspergillus flavus, which decreased gradually with GG, GA, and AA (37.5%, 20.8%, and
0%, respectively).
Conclusions: Psoriasis cases are significantly associated with fungal growth, which
may be a contributing factor in its pathogenesis. SNPs of IL-17A
(rs10484879) G/A
gene led to increased susceptibility toward pathogenesis of psoriasis. Fungal growth
and IL-17A
GA+AA genotypes are suggested to be independent predictors of psoriasis
susceptibility.
K E YWORDS
culture, fungal infections, IL-17A,