IgE et IgG, basophiles et neutrophiles : l’arbre et la forêt

Abstract

Classically, allergy depends principally on IgE antibodies and on high-affinity IgE receptors expressed on mast cells and basophils. IgG anti-allergen antibodies are however produced in much greater amounts than IgE antibodies. Using a mouse model of active anaphylaxis, we have demonstrated that systemic shock depends primarily on IgG antibodies, on activation of IgG receptors and on neutrophils. On the contrary, IgG receptors expressed on mouse and human basophils (from non-sensitized donors) have a predominantly negative effect over positive signals triggered by IgG or IgE antibodies. IgG antibodies may therefore exert antagonistic effects in allergy, depending on the cell type(s) involved. Antibodies that are 105-106-fold more abundant than IgE and blood cells that are 100-fold more numerous than basophils must therefore be considered to be major players in allergy.