Aberrant T cell regulation of IgE production in atopy

Atopy is associated with elevated serum levels of allergen-specific immunoglobulin E (IgE). IgE production is preferentially induced by the T cell-derived lymphokine interleukin-4 (IL-4) and is suppressed by interferon and prostaglandins, of which interferon-gamma (IFN-gamma) is produced by T cells. We review our studies on the question of whether atopy is associated with CD4+ allergen-specific T cells with an unbalanced lymphokine production. We prepared panels of housedust mite (Dermatophagoides pteronyssinus)-specific T lymphocyte clones (TLC) from atopic and non-atopic individuals and found that TLC from housedust mite-allergic patients produced IL-4 but not IFN-gamma, whereas such TLC from a non-atopic individual produced IFN-gamma and only in some cases small amounts of IL-4. Candida albicans- and tetanus toxoid-specific TLC, established from one of the atopic donors, also produced IFN-gamma without IL-4, suggesting that the atopic state is characterized by a defective accumulation of IL-4-producing CD4+ T lymphocytes into the allergen-specific T cell repertoire.