|Description:||Produced by the National Institute of Allergy and Infectious Diseases (NIAID), under a magnification of 100X, this photomicrograph of a human peripheral blood smear revealed the presence of activated eosinophils from a patient with idiopathic hypereosinophilic syndrome (HES), showing cytoplasmic clearing, nuclear dysplasia, and the presence of immature forms. Please see the Flickr link below for additional NIAID photomicrographs of various microbes.|
Classified as a myeloproliferative neoplasm (MPN), a sign of possible HES is a persistently elevated eosinophil count >1500 eosinophils/mm³, which takes place over a time period of at least six months. Even after a complete differential diagnostic study, the cause for this ailment will remains unknown, hence the term, idiopathic. Unless this disorder is treated with glucocorticoids, usually prednisone, HES will prove fatal. This disease usually involves the heart, nervous system, or the bone marrow.