The hypereosinophilic syndrome: analysis of fourteen cases with review of the literature.

Several closely related disease entities make up the idiopathic hypereosinophilic syndrome (HES). The syndrome is manifest by persistent and prolonged eosinophilia with organ damage. A group of 14 patients had hematologic, cardiac, and neurologic abnormalities attributable to this disease. Patient survival and response to chemotherapy was significantly better in this group than in previously reported patients. The etiology of HES remains unknown, as does the mechanism of tissue damage.