Alveolar macrophage and its participation in the inflammatory processes of allergic asthma

Purified alveolar macrophages (AM) obtained by bronchoalveolar lavage of allergic asthmatic patients are stimulated by incubation with anti IgE or the exposure to the related allergen. Confirming the demonstration of a receptor for the Fc fragment of IgE on the surface of macrophages, IgE was characterised on AMs by a rosette-assay, showing an increased percentage of cells forming rosettes with red blood cells coated with anti-IgE or the specific allergen. The IgE-dependent secretion of arachidonic acid metabolites, PAF-acether and chemotactic factors for neutrophils and eosinophils demonstrated in vitro, together with the in vivo demonstration of the activation of AMs by a local provocation test, suggest that besides mast cell, AM do participate in the inflammatory processes of allergic asthma.