neutrophils play a vital role in the protection of the organism against bacterial and mycotic infections. chronic severe neutropenia is defined as an absolute number of neutrophils under 500xmm3 that persist months or years. the causes of this condition are multiple. they may be congenital and exist since birth, or acquired and appear at any moment of life. the severe congenital neutropenias may appear isolatedly or they may be associated with complex genetic syndromes. among the first, clinical neutropenia and kostmann’s syndrome are of great interest due to the recent discovery of a mutation common to both affecting the neutrophil elastase gene (ela2). the use of the granulocytic colony stimulating factor has improved the prognosis of these entities
