Increased calcium uptake in the red cells of unsplenectomized patients with hereditary spherocytosis: significant contribution of reticulocytosis.

The presence of abnormal calcium (Ca) metabolism in the red cells of hereditary spherocytosis (HS) patients has long been in dispute. Thus, to clarify the discrepancies of experimental results published previously, Ca metabolism in the red cells was investigated in 12 unsplenectomized and 6 splenectomized HS patients. A marked increase of Ca uptake was observed in the ATP-depleted red cells of the unsplenectomized HS patients. The increased red cell Ca uptake was normalized after splenectomy in the same HS patients. The extent of increased Ca uptake was well correlated to the degree of reticulocytosis (p less than 0.001). The observation was confirmed by the fractionation studies of the HS red cells. Ca uptake was not increased in the spherocyte-rich bottom fraction, if reticulocytosis was not present. No significant difference was observed in red cell calcium content between normal and HS patients, neither unsplenectomized nor splenectomized.