DOI: 10.2340/0001555575357360

Evidence for a possible role of the lipophilic yeast Pityrosporum ovale in the pathophysiology of atopic eczema has been found both in laboratory and therapeutical studies. Positive type I prick test reactions to P. ovale correlate with the intensity of eczematous skin lesions in the head and neck regions of patients with atopic eczema. Furthermore, antifungal treatment has been shown to be helpful in atopic eczema. In the present study the effect of P. ovale on IgE synthesis and cytokine production (IL-2, IFN gamma, IL-4, IL-10) was investigated in patients with atopic eczema, in vitro. Eight patients with atopic eczema were studied; of these, 5 patients had specific IgE antibodies against P. ovale, as determined by fluoroimmunoassay (RAST). The control group consisted of 5 healthy non-atopic, P. ovale IgE-antibody-negative volunteers. Freshly isolated peripheral blood mononuclear cells (PBMC) were incubated in the presence of different antigen concentrations (0.01, 0.1, 1.0, 10 micrograms/l x 10(6) cells) of P. ovale. IgE contents in the cell culture supematants were significantly elevated in RAST(+) patients with atopic eczema (p < 0.05), compared with RAST(-) atopic eczema patients and healthy volunteers. Coincubation of P. ovale-stimulated PBMC with IL-4 (50 U/l/ 1 x 10(6) cells) resulted in a significantly higher IgE synthesis only in the RAST(+) atopic eczema patients. Additionally, incubation of PBMC from RAST(+) patients with atopic eczema led to an elevated synthesis of the TH2 related cytokines IL-4 and IL-10. Within the atopic eczema group, two subgroups differed markedly in their response to P. ovale antigen stimulation with a good correlation to the presence of specific IgE in serum and in vitro IL-4 and IL-10 production. The data support the assumption that P. ovale antigens might play a role in skin inflammation in at least a subgroup of patients with atopic eczema characterized by the presence of specific IgE antibodies to P. ovale.