Virulence gene expression in Malassezia spp from individuals with seborrheic dermatitis.

TO THE EDITOR Seborrheic dermatitis (SD) is a chronic inflammatory disease that compromises skin areas rich in sebaceous glands, such as the face, scalp, and upper trunk. The condition is frequently observed in acquired immune deficiency syndrome patients (30–85% compared with 3–5% of immunocompetent adults). Its appearance is considered to be an early marker of the evolutionary trend of HIV infection (Gupta et al., 2001; Gupta and Bluhm, 2004; Ashbee, 2007; Naldi and Rebora, 2009). The cause or causes of SD and the pathogenic role of Malassezia spp are, at present, not completely understood (Gupta et al., 2000; DeAngelis et al., 2005; Tajima et al., 2008). At this time, we can only rely on hypotheses of the pathogenicity mechanisms and the pathogenic determinants (Ran et al., 1993; Brunke and Hube, 2006; Xu et al., 2007). Analyses of the complete genome of Malassezia globosa and the partial genome of M. restricta (Xu et al., 2007) have presented gene-encoding enzymes of the lipase and phospholipase families that could explain the lipid dependency of the genus. The secretion of enzymes by human pathogenic fungi has been considered an important factor in the invasion and dissemination in the host (Staib et al., 1999; Descamps et al., 2002) and, thus, it is suggested that lipases and phospholipases are involved in the mechanisms of pathogenicity of Malassezia spp. However, except for an early approximation of M. globosa lipase gene expression on human scalp, the expression of these genes has never been tested during disease development (Xu et al., 2007). In order to assess the induction of lipases and phospholipases in SD, we analyzed the expression profiles of candidate virulence genes of Malassezia spp during host infection. A total of 40 Malassezia isolates were obtained from four groups of individuals (non-Malassezia lesion (NML), SD, NMLþHIV, and SDþHIV) (Table 1). The selection of SD and SDþHIV patients was based on dermatologist evaluation of the presence of erythema and peeling in areas such as the face and scalp. We assessed isolates for morphological and physiological features, and we confirmed their identification by amplification and sequencing of 5.8S rDNA-ITS2 regions (Supplementary Materials and Methods online). Six Malassezia spp strains were used as a reference (M. furfur CBS 1878, M. sympodialis CBS 7222, M. globosa CBS 7966, M. restricta CBS 7877, M. slooffiae CBS 7956, and M. pachydematis CBS 1879). All of the Malassezia species isolated from NML, SD, NMLþHIV, and SDþHIV individuals exhibited typical morphological, physiological, and molecular features (Supplementary Table S1 online), with the exception of one: M. Furfur, which presented atypical Tween assimilation pattern (Gonzalez et al., 2009). We found M. restricta to be the predominant species in all groups of individuals, and M. furfur was found in all groups except the SD group. M. furfur with an atypical Tween assimilation pattern was present only in SDþHIV individuals, and M. globosa was present in SD and SDþHIV individuals. These results coincide with previous reports (Tajima et al., 2008; Oh et al., 2010). For the expression assays, four genes, Mgl0797/M. globosa LIP1, Mgl0798/M. globosa hypothetical secretory lipase, Mgl3326/M. globosa hypothetical phospholipase, and Mflip 1/M. furfur MfLIP1 were used for a quantitative analysis using real-time PCR (Supplementary Table S2 online). All the genes were detected in all samples.