[Anti-IgE and future treatments for respiratory allergies]

Immediate hypersensitivity remains the fundamental mechanism of respiratory allergy, emphasizing the importance of the antigen-immunoglobulin (IgE) reaction. Development of innovating treatments has naturally centered on a search for compounds inhibiting the IgE response, in particular anti-IgE antibodies. Humanized anti-IgE antibodies have been recently developed for administration in humans. These antibodies are designed to form complexes with circulating IgE which can be eliminated. The first trials have demonstrated an efficacy in allergic asthma, expressed by a significant decrease in consumption of systemic steroids in severe asthma. Other work has also showed a lower number of hospitalizations for acute asthma. Other therapeutic approaches have focused on limiting the production of IgE by an effect on the auxiliary lymphocyte balance, or more generally, by inhibiting the Th2 response while favoring the Th1 response. Early results obtained with anti-IL-5 were disappointing since the decrease in the eosinophilic response was not associated with any alteration in bronchial hyperreactivity. Administration of IL-12 has given similar results but the first trials with nebulized anti-IL-4 are more promising.