IGE-BINDING COMPONENTS OF WHEAT, RYE, BARLEY AND OATS RECOGNIZED BY IMMUNOBLOTTING ANALYSIS WITH SERA FROM ADULT ATOPIC-DERMATITIS PATIENTS

The allergen extracts of wheat, rye, barley and oats flours were characterized by IgE-immunoblotting with serum samples from 40 adult patients; 35 patients with atopic dermatitis, one with rhinitis and four with urticaria. All these patients had been positive when skin-prick testing was carried out with one or more of the four flour extracts or displayed one or more positive cereal RAST results. Four non-atopic sera were used as negative controls. Acidic and neutral protein extracts of wheat, rye, barley and oats flours were processed for the immunoblotting experiments and 35 patients appeared positive in IgE immunoblotting with wheat and rye, 32 with barley and 33 with oats. The IgE immunoblots showed polyspecific binding patterns; wheat exhibited 36 IgE stained bands, rye 35, barley 33 and oats 10. Eighteen of the IgE stained bands could be classified as intermediate allergens for wheat, 23 for rye and 15 for barley. The 66 kDa protein in oats was visualized by 28 out of 33 sera (84%), however, there was evident non-specific binding to this region and thus it may also represent lectin-like binding. The most frequent staining with wheat extract was seen in the 26 kDa protein region (15/35, 43%), with rye in the 40 kDa (16/35, 46%) and with barley in the 26 and 46 kDa protein bands (14/32, 44%). Simultaneous staining with wheat, rye and barley extracts were observed with 16 bands suggesting crossreactivity between these cereals.