Erythrocyte membrane defects in hemolytic anemias found through derivative thermal analysis of electric impedance

Hereditary hemolytic anemias originate mainly from defects in hemoglobin and plasma membrane proteins. Here, we propose a new method, thermal analysis of impedance, sensitive to membrane defects. It detects three processes in erythrocyte membrane; fall in membrane capacity at 49.5 °C and activation of passive PO42+ permeability at 37 °C and inorganic ions at 61.5 °C. The denaturation of spectrin is involved in the first process whilst the anion channel is involved in latter processes. Using this method three persons with xerocytosis were found whereby the fall in membrane capacity and spherization of erythrocytes were both postponed (53 °C) compared to control (49.5 °C). In contrast to control cells, strong activation of passive permeability for Cl− at 37 °C and sucrose at 61 °C were detected that were both eliminated by pre-inhibition of the anion channel with 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid (DIDS). In addition, erythrocytes from 15 patients with various forms of anemia were studied in intact state and after refreshment. The results were compared with the data of clinical laboratory and osmotic fragility test. The final conclusion is that this method detects membrane defects with altered spectrin and anion channel syndrome (hereditary xerocytosis, spherocytosis, poikilocytosis and pyropoikilocytosis, elliptocytosis and stomatocytosis) and, after refreshment, helps differentiate them from the anemia with hemoglobinopathy.