Demonstration of Species‐Specific Sensitization to Major Allergens of Dermatophagoides Species by Solid‐Phase Absorption of Human IgE Antibodies

Twenty-five mite-allergic patients in the Brussels area were tested with the skin-prick test (1, 5 and 10 histamine equivalents by prick test (HEP] and RAST with standardized extracts of Dermatophagoides pteronyssinus (Dp) and D. microceras (Dm). Highly significant correlations (0.69 less than rS less than 0.96) between the two species coincided with marginal, but highly significant (P less than 0.01), greater reactions to Dp in all comparisons. Species-specific IgE antibodies to antigen Dp-42 (= P1) and Dp-X were readily detected by solid-phase serum absorption with heterologous antigen and subsequent crossed radioimmunoelectrophoresis (CRIE). An absorption single radial immunodiffusion (SRID) technique, involving major allergens Dp-42, Dm-6 and Df-6 of Dp, Dm and D. farinae (Df), demonstrated the presence of IgE antibodies reacting with epitopes common to all species, epitopes common to two species, absent on the third, and epitopes strictly specific for Dp. The majority of patients with a strong IgE binding reacted to both common and strictly species-specific epitopes. The serological findings were in good agreement with the exposure situation in the area: by species-specific ELISA for dust allergen content, Dp occurred as the dominating species, 20 out of 24 homes having dust levels of Dp-42 above 30 ng/g. Five and four homes had detectable levels of Dm-6 and Df-6, respectively, in dust.