Sensitization rate of Trichophyton spp. allergen in various allergic diseases and identification of its allergens with immunoblotting

Abstract

Background: Trichophyton is one of the most common genera of dermtophytes. It has been reported that Trichophyton spp. might be one of the causative allergens in patients with asthma, rhinitis, urticaria and angioedema. Objectives: To analyze the sensitization rate of Trichophyton, to determine serum specific IgE antibody, and to confirm Trichophyton as a causative antigen in patients with allergic diseases. Methods: A total of 1,806 patients were enrolled in this study. Skin prick test was performed with 50 common inhalant allergens and 20 food allergens. Serum specific IgE antibodies were determined by ELISA using Trichophyton mentagrophytes antigen in 60 patients among positive skin responders to Trichophyton antigens and in 20 controls. For evaluation of cross-reactivity between Trichophyton and other fungal species, competitive ELISA inhibition test was performed. SDS-PAGE and IgE-immunoblot analysis using T. mentagrophytes antigen were applied in 7 patients with high specific IgE titers. Results: 102 patients (5.7%) showed positive response to T. mentagrophytes on skin prick test, and six patients showed isolated positive responses. Serum specific IgE increased according to skin reactivity (p<0.05). SDS-PAGE and IgE-immunoblot showed 10 IgE-binding components (11, 17, 27, 32, 35, 38, 42, 48, 49, 51 kDa) within Trichophyton extracts. Trichophyton-ELISA inhibition test showed dose-dependent inhibitions with additions of Trichophyton antigens, while minimal inhibitions were noted with additions of Fusarium, Alternaria, Aspergillus and Cladosporium. Conclusions: Trichophyton could induce IgE sensitization in allergy patients. The sensitization rate on skin prick test was 5.7%. Trichophyton antigen should be included in skin prick test battery to screen causative agents for allergy patients.