Antigenic components of Malassezia species for immunoglobulin E antibodies in sera of patients with atopic dermatitis

The role of Malassezia in atopic dermatitis affecting the head and neck of adults

Atopic dermatitis is a common chronic skin condition. A subset of patients with head and neck dermatitis may have a reaction to Malassezia flora fueling their disease. Although there are no documented differences in Malassezia species colonization, patients with head and neck atopic dermatitis are more likely to have positive skin prick test results and Malassezia-specific IgE compared with healthy control subjects and patients with atopy without head and neck dermatitis. There is no clear relationship with atopy patch testing. The reaction to Malassezia is likely related to both humoral- and cell-mediated immunity. Clinically, Malassezia allergy may be suspected in patients with atopic dermatitis and: (1) head and neck lesions; (2) exacerbations during adolescence or young adulthood; (3) severe lesions recalcitrant to conventional therapy; and (4) other atopic diseases. There is literature to suggest that these patients will benefit from a 1- to 2-month course of daily itraconazole or ketoconazole followed by long-term weekly treatment.

Detection and quantification of specific IgE antibodies against eight Malassezia species in sera of patients with atopic dermatitis by using an enzyme-linked immunosorbent assay

The lipophilic yeast Malassezia, a member of the cutaneous microflora, is an exacerbating factor in atopic dermatitis (AD). Of the 11 currently recognized species, M. globosa and M. restricta are found to frequently colonize the skin of AD patients. In this study, we attempted to quantify specific IgE antibodies against eight Malassezia species, namely, M. dermatitis, M. furfur, M. globosa, M. obtusa, M. pachydermatis, M. slooffiae, M. sympodialis, and M. restricta, in sera from AD patients by using an enzyme-linked immunosorbent assay (ELISA). The specific IgE value against M. restricta was greater than those against other Malassezia species. Competitive ELISA inhibition tests revealed that M. restricta contained species specific as well as shared antigens. Therefore, M. restricta could be considered as a candidate diagnostic antigen for detecting anti-Malassezia IgE in sera from AD patients.

Recent developments in the immunology and biology ofMalasseziaspecies

Malassezia spp. are members of the normal cutaneous flora, but are also associated with several cutaneous diseases. Recent studies of the interaction of Malassezia spp. with melanocytes, fibroblasts, keratinocytes and dendritic cells have highlighted their potential to modulate the immune response directed against them. In normal skin they may downregulate the inflammatory response, allowing them to live as commensals. In contrast, in atopic/eczema dermatitis syndrome and psoriasis, they may elicit an inflammatory response that contributes to the maintenance of lesions. Future research may define ways to influence this inflammatory cycle and hence to control or prevent exacerbations of these diseases.

Malassezia yeasts in the pathogenesis of atopic dermatitis

Atopic dermatitis is a common skin condition, the aetiology of which is multifactorial, involving genetic, immunological and environmental factors. In recent years, it has been suggested that various microbial organisms may also be involved in the pathogenesis of the disease. Yeasts belonging to the Malassezia genus have received particular attention. These yeasts, known to be a part of the normal skin flora, have been shown to be capable of inducing immunoglobulin (Ig)E-mediated and T-cell mediated immune responses postulated to contribute to chronic inflammation in the skin, particularly in the head and neck region, where colonization with Malassezia is the greatest. Considerable evidence now exists to support this idea, raising the possibility that specific antifungal therapy may be a useful treatment measure in some atopic patients who have a head and neck pattern of dermatitis.

Skin diseases associated with Malassezia species

The yeasts of the genus Malassezia have been associated with a number of diseases affecting the human skin, such as pityriasis versicolor, Malassezia (Pityrosporum) folliculitis, seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and--less commonly--with other dermatologic disorders such as confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection. The study of the clinical role of Malassezia species has been surrounded by controversy because of their fastidious nature in vitro, and relative difficulty in isolation, cultivation, and identification. Many studies have been published in the past few years after the taxonomic revision carried out in 1996 in which 7 species were recognized. Two new species have been recently described, one of which has been isolated from patients with atopic dermatitis. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia. It also highlights the importance of individual Malassezia species in the different dermatologic disorders related to these yeasts.

Detection of Mala f and Mala s allergen sequences within the genus Malassezia

Malassezia species are opportunistic yeasts that are involved in the pathogenesis of a number of skin diseases including atopic eczema/dermatitis syndrome. Previously, we cloned six allergens from Malassezia sympodialis isolate ATCC 42132; these allergens are designated Mala s 1, and Mala s 5-Mala s 9. Three additional allergens, Mala f 2-Mala f 4, have been isolated from M. furfur by other investigators. The objective of the present study was to investigate the presence of these Mala sequences in seven Malassezia species. Genomic DNA amplification by PCR and sequencing showed that M. globosa, M. obtusa and M. sympodialis contain DNA sequences corresponding to all the allergens except Mala f 2 and Mala f 3. M. pachydermatis contains Mala s 1, Mala f 4, and Mala s 5-Mala s 8. M. restricta and M. slooffiae possessed Mala f 4 and Mala s 6. M. furfur was seen to possess Mala f 2-Mala f 4 as well as Mala s 5-Mala s 7. Our data from reverse-transcriptase PCR showed a more species-specific pattern of amplification. M. furfur evidenced expression of Mala f 2-Mala f 4. M. globosa and M. obtusa appeared to express only Mala s 6. M. pachydermatis expressed Mala f 4, Mala s 6, and Mala s 8, while M. restricta and M. slooffiae expressed Mala f 4 and Mala s 6. M. sympodialis expressed all the allergens except Mala f 2 and Mala f 3. Different Malassezia species appear to contain both common and species-specific allergen sequences.

Sequence diversity of the intergenic spacer region of the rRNA gene of Malassezia globosa colonizing the skin of patients with atopic dermatitis and healthy individuals

The lipophilic yeast Malassezia globosa is one of the major constituents of the mycoflora of the skin of patients with atopic dermatitis (AD). We compared the genotypes of M. globosa colonizing the skin surface of 32 AD patients and 20 healthy individuals for polymorphism of the intergenic spacer (IGS) 1 region of the rRNA gene. Sequence analysis demonstrated that M. globosa was divided into four major groups, which corresponded to the sources of the samples, on the phylogenetic tree. Of the four groups, two were from AD patients and one was from healthy subjects. The remaining group included samples from both AD patients and healthy subjects. In addition, the IGS 1 region of M. globosa contained short sequence repeats: (CT)(n), and (GT)(n). The number of sequence repeats also differed between the IGS 1 of M. globosa from AD patients and that from healthy subjects. These findings suggest that a specific genotype of M. globosa may play a significant role in AD, although M. globosa commonly colonizes both AD patients and healthy subjects.

IgE-reactivity to seven Malassezia species

BACKGROUND

Malassezia yeasts play a role in the pathogenesis of atopic eczema/dermatitis syndrome (AEDS). The revised genus Malassezia includes several species which all are natural habitants of the human skin. In this study, we evaluated the presence of immunoglobulin E (IgE) antibodies to different Malassezia spp. in AEDS patients to allow optimization of the characterization of the IgE antibody profile of IgE-associated AEDS.

METHODS

Ninety-six adult patients, with a clinical diagnosis of AEDS, were included in the study. Seventeen of the patients had IgE antibodies to M. sympodialis, ATCC 42132 (m70 ImmunoCAP, Pharmacia, Diagnostic AB, Uppsala, Sweden). The IgE antibodies to seven Malassezia spp. were measured and inhibition immunoblotting was performed to investigate whether M. sympodialis contains all the allergen components present in the other Malassezia spp.

RESULTS

Twenty per cent of 79 AEDS patients with a negative m70 ImmunoCAP test had IgE antibodies to at least one of the other six Malassezia spp. tested. Our inhibition studies indicated that Malassezia spp. to a great extent, share allergenic determinants. However, Malassezia species also contained species-specific allergens.

CONCLUSION

The use of only one species of Malassezia is not sufficient to detect all patients IgE sensitized to Malassezia. To obtain an optimal allergen preparation both common allergenic components as well as species-specific allergens have to be considered.

Effects of topical vehicles on growth of the lipophilic Malassezia species

In the present study, the abilities of major Malassezia species, M. sympodialis, M. globosa and M. furfur, to assimilate topical agents, which have been widely used as a material of ointment for skin diseases, were tested. Obvious growth of M. furfur on GYEP agar plate was noted in the presence of white petrolatum, purified white petrolatum, hydrophilic ointment and heparinoid in hydrophilic ointment, and also M. sympodialis showed similar growth when they were cultured with hydrophilic or heparinoid in hydrophilic ointment. In contrast, M. globosa did not grow on GYEP in the presence of the any topical agents tested. These results suggest that Malassezia species, especially M. furfur and M. sympodialis, assimilate several topical agents and showed the drug-depended cell growth.