[Neutrophils without CD16b receptors].

Occurrence of the rare CD16b deficiency ("null" phenotype) in neutrophils from two female patients (41 and 15 years old) is reported. The first case was referred with a diagnosis of anemia related to paroxistic nocturnal hemoglobinuria and the second case, with presumptive diagnosis of immune neutropenia. In both cases, absence of CD16b expression was determined by flow cytometry without deficiencies of other neutrophil alloantigens or defects of membrane anchorage through glycosil phosphatydil inositol (GPI) linkage.