Studies on calcium transport and calcium-dependent adenosine triphosphatase activity of erythrocyte membranes in hereditary spherocytosis.

Evidence has been recently presented of a relative deficiency of Ca2+ - dependent adenosine triphosphatase activity of erythrocyte membranes obtained from patients with hereditary spherocytosis. We have sought to confirm these findings by measuring calcium efflux from intact erythrocytes of patients with hereditary spherocytosis, as well as erythrocyte calcium concentrations, but find both these parameters to be normal. Ca2+-dependent adenosine triphosphatase activity, as well as Ca2+ -dependent membrane phosphorylation was also not found to be deficient in erythrocyte membranes from subjects with hereditary spherocytosis. These studies do not support the postulate that an accumulation of calcium affects the deformability of erythrocytes and their subsequent destruction in the spleen.