[Differential diagnostics of hypereosinophilia].

Hypereosinophilia is characterized by chronic increase of peripheral blood eosinophiles with common damage to vari-ous organs due to eosinophilic infiltration and release of mediators. Hypereosinophilia should be both reactive and clonal, and accompanies group of heterogeneous disorders (infectious, pulmonary, immunologic, malignant). Based on recent advances in molecular and genetic diagnostic techniques and increasing experience with differences in clinical features and prognosis, some subtypes of clonal hypereosinophilic syndromes have been defined, such as myeloproliferative variants, including chronic eosinophilic leukemia, and lymphocytic variants, but other subtypes remain undefined. Differential diagnostics oh hypereosinophilie therefore remains one of very important medical issues.Key words: differential diagnostics - hypereosinophilia.