Pityrosporum and Candida specific and non-specific humoral, cellular and cytokine responses in atopic dermatitis patients

Background Recent cytokine (RT-PCR, ELISA) analyses of inflammation in atop ic dermatitis (AD) have suggested a role for IL-4, IL-5 and IFN gamma. Pity rosporum ovale and Candida albicans are important allergens in some patient s with AD of the seborrhoic head, neck and shoulder region. In AD patients, the saprophytic yeasts induce IgE responses while they usually induce TH1 type responses. The cytokine responses induced by yeasts in AD are sparsely investigated. Objective To characterize the P. ovale- and C. albicans-specific and non-sp ecific humoral, lymphoproliferative and cytokine (IL-2, 4, 5 and IFN gamma) responses in AD. Methods Fifteen AD patients and seven healthy controls (HC) were included. Ficoll-isolated PBMC were stimulated by PHA and laboratory-generated extrac ts of P. ovale and C. albicans. Lymphocyte proliferation was measured by H- 3-thymidine incorporation and cytokine production by sandwich-ELISAs. The a ntigen-specific IgG and IgE antibodies were analysed by ELISA and nitrocell ulose RAST. Results Pityrosporum ovale- and C. albicans-specific IEE (both P < 0.001) a nd P. ovale-induced PBMC proliferation (P < 0.02) were elevated in AD. In g eneral, the IL-4/IFN gamma ratio induced by P. ovale was higher than that i nduced by C. albicans (P < 0.01). The PHA-induced IL-2 (P < 0.05) and IL-4 responses (P < 0.005), and the C. albicans-induced IL-5 response (P < 0.02) and IFN gamma response (P < 0.01), were elevated in AD. A network of corre lations was seen between serum total and the yeast-specific IgE, P. ovale-s pecific lymphoproliferation, PHA-induced IL-2, IL-4 and IL-5, and C. albica ns-induced IL-5. Conclusion The cytokine profiles found in this study support the role of TH 0 or TH1 cells by the side of TH2 cells in the pathogenesis of atopic derma titis. Pityrosporum ovale appears to be associated more with IL-4 responses and C. albicans with IFN<gamma> responses.