Reactivity of anti-Blomia tropicalis IgG and IgE in patients with atopic dermatitis

Patients with atopic dermatitis (AD) commonly develop antibodies of subclasses IgG and IgE to house dust mites, such as Dermatophagoides pteronyssinus and D. farinae. The domestic mite Blomia tropicalis is prevalent in Brazil and can cause the exacerbation of AD. The objectives of this study were to assess skin reactivity to B. tropicalis extracts of AD patients and a control group of nonallergic subjects, and to determine the in vitro reactivity of anti-B. tropicalis IgG and IgE in the serum of AD patients and a control group of nonallergic individuals. Subjects were 36 patients with confirmed AD and the controls were 25 nonallergic individuals. Skin sensitivity to B. tropicalis extracts was tested by the prick-test, and anti-B. tropicalis IgG reactivity in the serum was detected by the Western blot. Anti-B. tropicalis IgE reactivity in the serum was measured by RAST. Patients with AD reacted 7.12 times more often to extracts from B. tropicalis than the control group. A positive association was observed between the presence of anti-B. tropicalis IgG and IgE and AD. AD patients showed a high degree of sensitization to B. tropicalis; it can thus be considered a risk factor for the development of AD exacerbations in patients exposed to this mite species.