T cell responses in allergic rhinitis, asthma and atopic dermatitis

Although clinical responses to allergens have been shown to primarily involve IgE antibodies, there is often no clear correlation between the amount of allergen-specific IgE present in the serum and the nature and severity of allergic symptoms. This observation raises the question of the possible role of non-IgE mediated types of immune responses in this reaction. It is not known to what extent components of T cell-mediated immunity are involved in IgE-mediated reactions but several observations suggest an association between atopic disease and alterations in cellular immune function. These include the frequent association of high serum IgE levels with: (i) several of the primary and acquired immunodeficiencies characterized by partial T cell deficiency; (ii) the defective cell-mediated immunity and resultant recurrent infections seen in the hyper-IgE syndrome; and (iii) the sudden rise in serum IgE levels associated with reduced numbers of suppressor T cells in bone marrow transplant recipients during the acute graft vs host disease. In this review, we will examine the recent evidence suggesting that the T lymphocyte may play a primary role in the pathogenesis of atopic disorders.