CROSS-REACTING ALLERGENS IN TREE POLLEN AND POLLEN-RELATED FOOD ALLERGY - IMPLICATIONS FOR DIAGNOSIS OF SPECIFIC IGE

Background: A number of recombinant allergens are by now constituents of devices that can be routinely used for the detection of specific Ig E. Therefore, the results of diagnostic procedures using conventional allergen extracts can be compared with those employing selected recomb inant allergens. Methods: Thirty-four sera from patients allergic to b irch pollen were tested with the standard t3-CAP(TM) and rBet v 1a- an d rBet v 2-CAP(TM). cDNA was prepared by RT-PCR using primers accordin g to the N terminus of purified allergens. Expression cDNA libraries w ere screened with IgE from selected patients. Results: Twenty-four pat ients allergic to birch pollen showed the same RAST class with t3 as w ith rBet v la; 8 patients differed within 1 RAST class. In addition, 3 patients showed RAST class 3 with rBet v 2. Besides Bet vl and Bet v 2, 3 allergens from celery and avocado belonging to highly conserved p rotein families were cloned and sequenced. Conclusions: rBet via can b e expected to represent an excellent tool for the diagnosis of patient s allergic to birch pollen in Central, Northern, and Eastern Europe. S till, a much higher number of patients has to be tested. For their hig h degree of conservation, further protein families have to be identifi ed to explain cross-reactivities of birch pollen allergens other than Bet v 1 and Bet v 2 with, e.g., allergens from vegetable food.