Allergenic crossreactivity between Lepidoglyphus destructor and Blomia tropicalis

In general, the non-pyroglyphid mites Lepidoglyphus destructor and Blomia tropicalis show a different geographical distribution. Allergic sensitization to both species have been demonstrated in several investigations. However, whether this reflects cross-reactivity or dual sensitization is so far not known.

The aim of the study was to investigate the allergenicity and allergenic crossreactivity of L. destructor and B. tropicalis using sera from Sweden and Brazil.

Allergens in extracts of L. destructor and B. tropicalis were identified with SDS-PAGE and immunoblotting and the crossreactivity was studied by an immunoblot inhibition method. In addition to mite extracts, a recombinant major allergen of L. destructor, Lep d 2, was used.

The extract prepared from L. destructor contained 21 IgE-binding components when using the Swedish or the Brazilian sera. A 15 kDa allergen was recognized by 85% of the Swedish sera and 78% of the Brazilian. The B. tropicalis extract exposed 23 IgE-binding components when the Brazilian sera were used and 19 when the Swedish sera were used. A total of 83% of the Brazilian sera and 80% of the Swedish sera identified a 14.5 kDa allergen. The IgE response of the Swedish serum pool to 10 B. tropicalis allergens was inhibited by L. destructor extract. Likewise, the response of the Brazilian serum pool to four different L. destructor allergens was inhibited by B. tropicalis extract. The recombinant Lep d 2 allergen inhibited 33% of the IgE binding of the Swedish serum pool to the 14.5 kDa allergen in the B. tropicalis extract.

Crossreactivity with several proteins from L. destructor and B. tropicalis was demonstrated. The results suggest that a B. tropicalis 14.5 kDa allergen is antigenically crossreactive with recombinant L. destructor allergen Lep d 2.