Eosinophil lysis and free granules: an in vivo paradigm for cell activation and drug development

Release of cytotoxic granule proteins from activated eosinophil granules is considered to be a key pathogenic mechanism in eosinophilic diseases. Degenerated eosinophils and extracellular eosinophil granules have been repeatedly depicted. The present overview describes evidence that eosinophil lysis and distribution of free eosinophil granules (as opposed to 'classical degranulation') is an important mechanism by which eosinophils affect their surroundings. Here, Carl Persson and Jonas Erjefält summarize how recent reports on the induction of eosinophil lysis in vivo provide a new paradigm for eosinophil activation and thus constitute a novel basis for pharmacological manipulations in eosinophilic diseases.