The effects of Malassezia on pro-inflammatory cytokine production by human peripheral blood mononuclear cells in vitro

Abstract

Malassezia spp., the causative agents of pityriasis versicolor, are members of the normal human cutaneous microflora. Utilizing a combination of both enzyme‐linked immunosorbent assay (ELISA) and bioassay, we have investigated the ability of both formalin‐preserved and viable Malassezia (serovars A, B and C) to modulate pro‐inflammatory cytokine (IL‐6, IL‐1β and TNF‐α) release by human peripheral blood mononuclear cells (PBMNC) in vitro, over a 48‐h co‐incubation period. The results demonstrated that formalin‐preserved Malassezia (serovars A, B and C) at midexponential phase were generally able to induce a pro‐inflammatory cytokine response at a yeast cell to PBMNC ratio of 1:1. In addition, the results consistently demonstrated that at a yeast cell to PBMNC ratio of 20:1, formalin‐preserved Malassezia, irrespective of serovar, growth phase or PBMNC donor, were capable of significantly (P<0·05) decreasing the release of both immunochemical IL‐6 and IL‐1β plus bioactive IL‐1β and TNF‐α below that of unstimulated culture medium control values. This was apparent following 24‐ and 48‐h co‐incubation times, where maximal cytokine production was detected after 24 h. Similar results were obtained for the effect of viable Malassezia on pro‐inflammatory cytokine release by PBMNC. Our results suggest that a possible inhibitory component, present perhaps within the cell wall of Malassezia, was responsible for this depressive effect on pro‐inflammatory cytokine production.

Distribution ofMalasseziaspecies in seborrhoeic dermatitis: correlation with patients’ cellular immune status

“…The results of the study of Kesavan et al. show that Malassezia yeast significantly reduces the production of pro‐inflammatory cytokines, 29 which is related to the presence of lipid‐rich microfibrillar layer surrounding yeast cells. High quantity of lipid may prevent the yeast cell from inducing inflammation what is in consistent with their commensal status.…”

Interesting effect of Malassezia spp. infection on dermatoses of other origins

“…Studies have shown that Malassezia furfur modulates proinflammatory and immunomodulatory cytokine synthesis in the keratinocyte cell line by suppressing interleukin‐1α (IL‐1α), IL‐6 and tumor necrosis factor‐α (TNF‐α) and by upregulating IL‐10 and TGF‐β1 4 . When Malassezia yeast cells were co‐cultured with human peripheral blood mononuclear cells (PBMNC), they were found to be capable of significantly decreasing the release of IL‐6, IL‐1β, and TNF‐α by human PBMNC 5 . However, the extraction of lipid from the yeast cells reversed this capacity to reduce proinflammatory cytokine synthesis; this suggests that the lipid microfibrillar layer of Malassezia spp.…”

The Effect of Detergents on the Morphology and Immunomodulatory Activity ofMalassezia furfur

“…Removal of the capsule-like layer reverses the suppression of cytokine production by monocytes 7 . Kesavan et al 6 have examined the effect of the Malassezia species with and without the capsular layer on the cytokine production by monocytes. As a result, the levels of IL-1α, IL-6 and TNF-α production were lower in the Malassezia with the capsular layer, suggesting that the capsule suppresses the release of proinflammatory cytokine and it prevents an inflammatory response 7 .…”

“…It is thought that the lipid-rich layers play a critical role in physiologic and pathologic conditions. According to Kesavan et al 6 , Malassezia furfur (M. furfur)…”