Journal de recherche clinique et expérimentale en dermatologie
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Relationships among the Genotypes of Malassezia Globosa Colonizing Patients with Atopic Dermatitis, the Clinical Severity of the Disease, and the Level of Specific IgE Antibodies

Otomi Cho, Mami Saito, Ryoji Tsuboi, Hiroshi Kato, Akemi Nishikawa, Sanae Nakajima and Takashi Sugita

Background: Various types of microorganisms colonize the skin surface, and some such as the bacterium Staphylococcus aureus and fungus Malassezia, exacerbate the symptoms of atopic dermatitis. Malassezia-specific IgE antibodies are present in the sera of patients with atopic dermatitis and the level thereof correlates with the severity of the condition. Malassezia has many genotypes. In the present study, we explored the relationships among the genotypes of Malassezia species colonizing patients with atopic dermatitis, the clinical severity of the disease, and the level of specific IgE antibody.

Methods: Scale samples were obtained from head or neck lesions of 74 patients with atopic dermatitis and 40 healthy subjects. The intergenic spacer (IGS) 1 region of the rRNA genes of M. globosa (the major flora of patients with atopic dermatitis) were amplified by PCR and directly sequenced. M. globosa-specific IgE antibody levels were determined using the AlaSTAT™ microplate system.

Results: Eighteen M. globosa IGS1 genotypes were detected in scale samples from patients with atopic dermatitis and healthy individuals. Of these, the proportion of the (GT)10:(CT)8 genotype increased with the clinical severity of disease and increasing levels of M. globosa-specific IgE antibodies, whereas this genotype was not found on the skin of healthy subjects.

Conclusion: A specific genotype of Malassezia selectively colonized the skin of patients with atopic dermatitis, contributing to the clinical severity of disease. Thus, a “bad Malassezia” may be present on the skin of patients with atopic dermatitis.