Cytosolic Free Calcium Concentration and Intracellular Calcium Distribution in Lymphocytes from Cystic Fibrosis Patients

Lymphocytes prepared from normal individuals and patients with cystic fibrosis (CF) were compared with regard to intracellular Ca2+ concentration, distribution, and handling. No difference between control and CF was found in the concentration of cytosolic free Ca2+ (98 +/- 5 vs 102 +/- 7 nM), and no difference was observed in the kinetics with which control and CF cells restored cytoplasmic Ca2+ toward normal following a perturbation induced by cold-exposure. However, total intracellular Ca2+ is about 25% higher in CF lymphocytes than in control. Of this excess Ca2+, about 50% appears to be sequestered in mitochondria. This suggests that some difference in Ca2+ handling does exist, but the significance of this in cystic fibrosis remains to be determined.