Increased neutrophil adhesive capability in Cohen syndrome, an autosomal recessive disorder associated with granulocytopenia.

[cohen syndrome]

Cohen syndrome is a multiple congenital anomalies-mental retardation syndrome associated with granulocytopenia . To date , the mechanisms involved in causing the neutropenia are unknown . In order to get insight into the mechanisms of neutropenia , we studied both the bone marrow and the functional properties of neutrophils obtained from peripheral blood (PB ) or skin window (SW ) exudate of a patient affected by Cohen syndrome .Assays of superoxide anion release (as reduction of cytochrome C ) and cell adhesion (quantified by measuring membrane acid phosphatase ) were carried out according to a microplate method whereby both parameters can be evaluated (Bellavite et al ., 1992 ). Neutrophil surface integrins and CD 6 2 L (selectin ) were evaluated by flow cytometry .Bone marrow did not show relevant morphological abnormalities in either erythroid or myeloid precursors . Cohen neutrophils exhibited a greater adhesive capability than control leukocytes in all the conditions studied (PB or SW , unstimulated or agonist-stimulated leukocytes ). Cytofluorometric evaluation of neutrophil beta 2 integrin (CD 11 b ) and selectin (CD 6 2 L ) showed a lower mean fluorescence intensity and a lower percentage of fluorescence conjugate monoclonal Ab -positive cells in the patient than in control subjects . Moreover , a double population of neutrophils , with different affinities to the specific monoclonal antibody anti-CD 11 b , was observed in the patient . Superoxide anion release , expression and distribution of fluorescence conjugate MoAb anti-human CD 11 a were normal .Neutrophil adhesive capability was greatly increased in a case of Cohen syndrome . Cytofluorimetric expression of CD 11 b and CD 6 2 L molecules was consistent with a generalized neutrophil activation in vivo .