Cross-reactivity of foods--mechanisms and clinical significance.

We have been most fortunate to witness advances in techniques related to the field of allergy. The development and implementation of RAST, RAST inhibition, crossed immunoelectrophoresis, and CRIE have allowed us to determine what food moieties have the potential to be allergenic. Furthermore, using the above techniques, it has become possible to delineate whether allergenic moieties in particular food stuffs share their allergenic determinants with other food materials. Despite these advances, it is difficult to make definite statements concerning clinically significant cross-reactivity among nuts, legumes, and crustacea. There is still, obviously, a role for the use of open and double-blind food challenges, as demonstrated by the peanut oil, soybean oil, and sunflower oil studies. Although food challenges, in situations where anaphylaxis is a possibility, should only be done under controlled circumstances and under the guidance of a well-defined protocol, this technique should remain available to further study cross-reactivity among foods. At the present time, the following conclusions concerning cross-reactivity among foods may be entertained. (1) Cross-reactivity among foods from different food groups is extremely rare. (2) Individuals having IgE-mediated reactions to legume proteins, for example peanut and soybean, do not respond to the corresponding oil derived from those substances. (3) Cross-reactivity among legumes may occur, but in vitro studies defining common allergenic determinants among these food substances cannot be automatically interpreted as reflecting in vivo cross-reactivity. Furthermore, very limited attempts at open and double-blind challenges in specific patients have not confirmed cross-reactivity in peanut-sensitive individuals to other legumes.(ABSTRACT TRUNCATED AT 250 WORDS)