Use of the erythrophagocytosis assay for predicting the clinical consequences of immune blood cell destruction.

The erythrophagocytosis assay is a useful parameter to evaluate the immune erythrocyte destruction occurring in vivo. The aim of this work was to use this assay in: a) the diagnostic and therapeutic assessment of autoimmune haemolytic anaemia (AIHA), b) the selection of blood for immunized patients requiring transfusion and c) the prediction of the severity of haemolytic disease of the newborn (HDN). This assay was also used to study the physiological removal of senescent erythrocytes from the circulation. The erythrophagocytosis assay was carried out incubating different erythrocyte suspensions and peripheral blood monocytes. A total of 200 monocytes were analysed to determine the percentage of active monocytes (% AM). We have demonstrated the usefulness of the erythrophagocytosis assay in the diagnosis of AIHA, mainly in patients with a negative direct antiglobulin test. This assay is also more adequate than classic immunohaematologic tests to obtain a better evaluation of the patients' response to treatment. The erythrophagocytosis assay was performed in immunized patients requiring transfusion and allowed us to select the least incompatible units. This method showed a better correlation with the newborns' clinical outcome than serological tests in cases of HDN. This functional assay also indicated an increased rate of erythrophagocytosis of senescent erythrocytes compared with young erythrocytes.