In vitro cross-reactivity between tomato and other plant allergens.

BACKGROUND

Cross-reactivity among fruits and different pollen and fruit species has been extensively reported.

OBJECTIVES

To investigate the in vitro cross-reactivity between tomato and pollen, fruit, and latex extracts and to identify the proteins involved.

METHODS

A serum pool was prepared from 18 individuals residing on the Spanish Mediterranean coast (9 men and 9 women; mean [SD] age, 27.4 [10.1] years) who had positive skin prick test reactions to tomato peel. Extracts from 10 pollens, 12 fruits, and latex were tested. Levels of specific IgE to each extract were measured. The allergenic profile was evaluated by means of immunoblot. The percentage of inhibition between extracts and tomato peel extract was analyzed by means of CAP inhibition, and the allergens implicated were elucidated by immunoblot inhibition.

RESULTS

For pollens, the highest specific IgE values were obtained for grasses. Most pollen extracts showed a capacity of inhibition similar to that of tomato peel extract; high percentages were obtained with Artemisia vulgaris and Poa pratensis. The most strongly inhibited allergens in tomato corresponded to bands of 32 and 45 kDa. For fruits, the highest value of specific IgE was detected for peach. High percentages of inhibition were obtained with peach and hazelnut. No inhibition was detected with latex. Peach, chestnut, and melon inhibited high molecular weight bands (32 and 45 kDa) and a band of approximately 10 kDa.

CONCLUSIONS

Cross-reactivity between tomato and pollen and fruit extracts has been demonstrated. Allergens with a high molecular weight range seem to be responsible in pollen extracts. A 10-kDa band seems to be responsible in Platanus acerifolia, Salsola kali, peach, chestnut, and melon.