Specific immunoglobulin E antibodies to saprophytic yeasts in sera of atopic patients allergic to house dust mites.

BACKGROUND Atopic dermatitis (AD) is a complex disease caused by genetic and environmental interactions. AD impairs skin barrier function, enabling microorganisms to penetrate and interact with the immune system. OBJECTIVES This study aimed to investigate the presence of specific immunoglobulin (Ig) E antibodies to the yeast species Candida pelliculosa, Candida guilliermondii, Candida famata, and Rhodotorula rubra in the sera of AD patients and to evaluate possible cross-reactivity between yeasts and allergens of Dermatophagoides pteronyssinus (D1) and Dermatophagoides farinae (D2). METHODS We analyzed serum samples from 14 healthy individuals and 34 AD patients: 19 were positive to D1 and D2 (Immulite) and 15 were negative. Determinations were made using enzyme-linked immunosorbent assay (ELISA), competitive ELISA, and the Immulite inhibition assay. RESULTS The results of ELISA showed that all house dust mite-positive sera had specific IgE antibodies to the yeast species tested: 42% of these sera reacted with all 4 yeast species. The inhibition study demonstrated partial cross-reactivity between IgE class antibodies with the yeast species. This finding indicates that different Candida species and R rubra have species-specific and cross-reactive antigens with partially overlapping epitopes, thus suggesting cross-reactivity with mite allergens. C pelliculosa protein extract inhibited IgE binding to D1 (63.4%) and D2 (71%) allergens. The inhibition value for D1 showed a significant correlation with the inhibition value for D2 (r = 0.669, P = .03; Spearman rank correlation). CONCLUSION The results of the present study suggest that C pelliculosa and house dust mites share common antigens.