Gleich's syndrome

Gleich's syndrome is a rare disorder characterized by episodic angioedema (swelling), elevated IgM antibodies, and eosinophilia (increased eosinophil granulocytes). First described in 1984, its cause is unknown. It is not a form of idiopathic hypereosinophilic syndrome, as it rarely causes organ damage. Recent studies suggest most cases are a subtype of lymphocyte-variant eosinophilia, involving aberrant T cells with a CD3-, CD4+ immunophenotype that overproduce cytokines like interleukin 5.