Observation of echinocytosis in eight patients: a phase contrast and SEM study.

We report eight cases of echinocytosis discovered after screening of stained smears. The presence of echinocytes was exceptional in adults and children but was more frequent in neonates. In all cases we confirmed the presence of abnormal red cells by careful examination of the blood in wet preparations observed in phase contrast and after glutaraldehyde fixation and processing for SEM. No discernible common denominator was found to explain the presence of echinocytes in the blood of our patients. No echinocytogenic factor could be demonstrated in the fresh plasma. Echinocytes appeared quickly in patients who received exchange transfusion or transfusion of normal red cells. By contrast, in vitro incubation in the presence of substrates allowing constant ATP level never resulted in the formation of echinocytes when normal red cells were suspended in patient's plasma.