Allergens eliciting cell-mediated reaction

IV. Requirements for Allergens Eliciting Cell-Mediated (Delayed-Type) Allergic Reactions... 

This chapter will review our current knowledge about the pathogenesis of allergic skin disorders, in particular atopic dermatitis (AD) and urticaria. Anti-lgE therapy has not been systematically studied in these skin diseases. Therefore we will discuss the role of IgE in their pathogenesis and provide a scientific rationale for use of anti-IgE treatment in these diseases. Recent studies indicate that the IgE molecule has a multifunctional role in these diseases, acting as both a target and a key player in the elicitation of allergen-induced immediate hypersensitivity reactions and cell-mediated responses. 

Patients sensitized to pollen allergens often develop an IgE response to cross-reactive food allergens. Birch pollen-related food may lead to an exacerbation of eczema in a subpopulation of patients with atopic dermatitis and sensitization to birch pollen allergens. A birch pollen-specific T-cell response could be detected in lesional skin of these responding patients. T-cell cross-reactivity between Bet v 1 and related food allergens can occur independently of IgE cross-reactivity in vitro and in vivo. This has been shown in atopic dermatitis patients who developed late eczematous skin reactions to cooked food which was shown to elicit T-cell but not IgE-mediated responses [11]. 

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