Human Fc?RIIA induces anaphylactic and allergic reactions.

ABSTRACT: IgE and IgE receptors (Fc?RI) are well-known inducers of allergy. We recently found in mice that active systemic anaphylaxis depends on IgG and IgG receptors (Fc?RIIIA and Fc?RIV) expressed by neutrophils, rather than on IgE and Fc?RI expressed by mast cells and basophils. In humans, neutrophils, mast cells, basophils, and eosinophils do not express Fc?RIIIA or Fc?RIV, but Fc?RIIA. We therefore investigated the possible role of Fc?RIIA in allergy by generating novel Fc?RIIA-transgenic mice, in which various models of allergic reactions induced by IgG could be studied. In mice, Fc?RIIA was sufficient to trigger active and passive anaphylaxis, and airway inflammation in vivo. Blocking Fc?RIIA in vivo abolished these reactions. We identified mast cells to be responsible for Fc?RIIA-dependent passive cutaneous anaphylaxis, and monocytes/macrophages and neutrophils to be responsible for Fc?RIIA-dependent passive systemic anaphylaxis. Supporting these findings, human mast cells, monocytes and neutrophils produced anaphylactogenic mediators after Fc?RIIA engagement. IgG and Fc?RIIA may therefore contribute to allergic and anaphylactic reactions in humans.

SUBMITTER: Jonsson F 

PROVIDER: S-EPMC3311274 | biostudies-other | 2012 Mar

REPOSITORIES: biostudies-other