Abstract 39

It has been reported that drugs as penicilline become allergenic after metabolism by biotransformation enzymes into reactive electrophils which can bind covalently to cellular macromolecules to form haptens. Biotransformation enzymes, including cytochrome P450's, are highly polymorphic and the activities may vary widely between individuals, determining not only the rate of elimination of toxic xenobiotic compounds, but also the formation of reactive metabolites. Although allergies are considered to be caused by allergenic proteins or protein fractions, the presence of low-molecular-weight secondary plant compounds in pollen and plant foods may also play an important etiologic role in the allergic response. These secondary plant compounds are metabolized by biotransformation enzymes to facilitate elimination from the body.

We hypothesized that biotransformation enzyme polymorphism is one of the factors that attributes to the susceptibility to develop an allergic response to foods. Biotransformation enzyme phenotypes (cytochrome P4501A2 (CYP1A2), xanthine oxidase (XO) and N-acetyltransferase (NAT) were compared by measurement of urinary caffeine metabolites in 30 children with food hypersensitivity reactions and 31 non-allergic, healthy children matched for sex and age. Fourteen children in the patient group had a positive IgE-RAST. We found that children in the patient group were more likely to have an extensive metabolizer phenotype for CYP1A2 as compared to the the control group (P<0.05, Chi-square 1). For the other biotransformation enzyme activities no significant differences were observed. The group with a positive IgE-RAST was analyzed separately. There was no specific relation between biotransformation phenotype and IgE-RAST confirmed allergy.

The results of our study suggest that an extensive metabolizer phenotype for CYP1A2 may predispose individuals to develop allergies or hypersensitivity reactions.