Seborrhoeic dermatitis is not caused by an altered immune response toMalasseziayeast

Abstract

The immune response of patients with seborrhoeic dermatitis and healthy age- and sex-matched controls was examined to test the hypothesis that an inadequate or inappropriate immune response to Malassezia yeast leads to seborrhoeic dermatitis. Antibody responses were examined using enzyme-linked immunosorbent assays (ELISAs) and Western blots and lymphocyte responses using lymphocyte proliferation assays. The level of IgG and IgM specific for whole yeast cells or extracted proteins of two isolates of M. furfur was tested in ELISA. A wide range of antibody levels was found but the patient and control groups were indistinguishable (n = 19), and the groups could not be distinguished by the pattern of Malassezia proteins recognized by their sera in Western blots. The average affinity of the subjects' antibodies specific for Malassezia cells or proteins was measured using ammonium thiocyanate dissociation. Most of the sera had moderate affinities corresponding to 50% dissociation at thiocyanate concentrations of 0.5-1.0 mol/L. There was no difference between patients and matched controls. The proliferation of the patients' lymphocytes in response to a number of M. furfur cell preparations was measured: whole cells, cytoplasmic proteins, cell walls, soluble molecules extracted from the cell walls using sonication, and a commercial preparation. There was a wide range of responses between individuals, but there was no difference between the three groups: patients with seborrhoeic dermatitis (n = 16), healthy controls (n = 16) and a group suffering from other inflammatory skin conditions (n = 15). The results do not support the hypothesis that an inadequate immune response to Malassezia yeast could lead to seborrhoeic dermatitis. Other possible pathological mechanisms include toxin production or lipase activity.

Dermatite seborreica

“…but rather an alteration in cellular immune response. 81,82 Neuber et al also reported an alteration in cellular immunity in SD. 83 Watanabe et al showed that M. furfur does not lead to cytokine production by the keratinocytes, whereas this occurs with the other species of Malassezia.…”

Immunology of Diseases Associated withMalasseziaSpecies

“…The most recent study, in 1998, found no significant differences in titers of IgG or IgM antibody between patients and controls (328). Western blots using the cytoplasmic antigen demonstrated recognition of bands ranging from around 30 kDa to over 116 kDa.…”

Oral Terbinafine in the Treatment of Multi-Site Seborrheic Dermatitis: A Multicenter, Double-Blind Placebo-Controlled Study

“…However, there is no definitive evidence supporting the association of SD with this pathogen. Several studies focusing on quantitative or qualitative determinations of yeasts and on the immune response to P. ovale in patients with SD produced conflicting results (18)(19)(20)(21). The association ofthis pathogen with SD rests mainly on the results of therapeutic studies demonstrating the efficacy of antifungal agents, especially ketoconazole (22)(23), which, otherwise, has an additional antiinflammatory activity (24)(25).…”