Erythrocyte membrane properties in cystic fibrosis.

The biochemical properties of the erythrocyte membrane have been studied in cystic 
fibrosis patients and in age-matched controls. No significant differences could be 
observed in either the concentration or composition of the principal membrane 
constituents. Contrary to previous reports, we found normal levels of the 
Mg2+-dependent and Ca2+ + Mg2+-dependent ATPase activities in CF preparations. However, 
a qualitative difference was observed in the Ca2+-dependent ATPase, since the 
enzyme had relatively greater activity at lower calcium concentrations in the 
cystic preparations. This effect on the membrane-bound Ca2+-ATPase is unlikely to 
represent a genetic defect in the enzyme itself but it may 
be connected with the mechanism of pathogenesis in cystic fibrosis. 