Allergen components of Dermatophagoides farinae recognised by serum immunoglobulin (Ig)E in Thai dogs with atopic dermatitis.

BACKGROUND: Dermatophagoides farinae (Der f) is a common allergen in dogs with atopic dermatitis (AD). However, the relevant components of Der f require further investigation. OBJECTIVES: We aimed to provide data on the immunoglobulin (Ig)E-binding specific components of Der f for further diagnostic and therapeutic applications. ANIMALS: Serum samples were collected from five healthy, nine Der f-allergic atopic and seven non-Der f-allergic atopic dogs identified based on an intradermal skin test. METHODS AND MATERIALS: We explored the component profiles of Der f extracts through 2D gel electrophoresis and IgE immunoblotting. The IgE-binding components in both groups of atopic dogs were analysed by mass spectrometry. RESULTS: The majority of Der f-allergic atopic dogs recognised Der f Alternaria alternata allergen 10 (Der f Alt a 10), elongation factor 1-alpha (EF1-α), gelsolin-like allergen Der f 16, Der f 28 and Der f 2. Der f 3, Der f 10, Der f 20 and Der f 32 were recognised as minor allergens. Alpha-enolase, serine protease, arginine kinase and a few hypothetical proteins were recognised components in both groups of atopic dogs. Unexpectedly, Der f 15 (chitinase) was found to be a minor component. CONCLUSIONS AND CLINICAL IMPORTANCE: Multiple IgE-binding allergens of Der f were identified in Thai atopic dogs. We propose that the specific antigen set that is bound by IgE, comprising Der f Alt a 10, EF1-α, gelsolin-like Der f 16, Der f 28 and Der f 2, could be used for future diagnostics and immunotherapy platforms.

Antibody levels to Malassezia pachydermatis and Staphylococcus pseudintermedius in atopic dogs and their relationship with lesion scores.

BACKGROUND: Elevated immunoglobulin E (IgE) levels to Malassezia or Staphylococcus species in human atopic dermatitis are related to the skin severity index; a similar association has not been reported in atopic dogs. OBJECTIVES: To investigate serum levels of allergen-specific IgE, total specific IgG and IgG subclasses (IgG1 and IgG2) for M. pachydermatis and S. pseudintermedius, and to correlate them with the severity of dermatitis in dogs. ANIMALS: Serum samples were collected from dogs categorized by age and disease status. Groups 1 and 2: <3-year-old healthy (n = 9) and atopic dogs (n = 9), respectively; and groups 3 and 4: ≥3-year-old healthy (n = 11) and atopic dogs (n = 14), respectively. METHODS AND MATERIALS: Antibody levels were measured by ELISA. The Canine Atopic Dermatitis Lesion Index (CADLI) was analyzed in relation to antibody levels. RESULTS: Specific IgE and total IgG against M. pachydermatis and S. pseudintermedius were significantly increased in atopic dogs of all ages. Although differences between atopic and healthy dogs, with regard to specific IgG1 and IgG2 levels to each microbe, varied in significance within age groups. No significant relationships were found between the CADLI and any specific immunoglobulin levels for both microbe types. CONCLUSIONS AND CLINICAL IMPORTANCE: In dog skin, microbes may act as allergens triggering inflammatory responses via IgE- and IgG-dependent pathway(s). The affinity of the IgG subclass produced may vary according to antigen type. Specific IgE levels may be related to clinical disease in dogs and not to skin lesion severity.