The influence of echinocytosis induced by ATP depletion on erythrophagocytosis was analysed. Monocytes were isolated from peripheral blood of healthy, rhesus-positive volunteers and cultured for a total time of 6 h at 37 degrees C with 5% CO2. Erythrocytes from the same donor, either fresh (discocytes) or incubated at 37 degrees C for 48 h (spheroechinocytes) were added. Phagocytosis was quantified by measuring the chemiluminescence of the ingested heme. The rate of phagocytosis was 0.03 +/- 0.15 discocytes per phagocytic cell and 0.01 +/- 0.08 spheroechinocytes per phagocytic cell. Autologous serum did not affect this rate. The addition of anti-RhD immunoglobulins, however, increased phagocytosis drastically for discocytes and spheroechinocytes (4.22 +/- 2.09 and 5.24 +/- 2.58 erythrocytes per phagocytic cell, respectively). It is concluded that spheroechinocytosis induced by metabolic depletion, certainly one of the most severe forms of erythrocyte shape abnormalities, does not stimulate monocytes to remove these cells.