Abnormal fatty acid turnover in the phospholipids of the red blood cell membranes of cystic fibrosis patients (in vitro study).

A study was carried out in order to investigate whether the abnormal in vitro turnover of fatty acids in the phospholipids of the red blood cell membranes of cystic fibrosis patients is intrinsic to the membrane, or whether it is induced by extrinsic serum factors. Red blood cells of cystic fibrosis patients and healthy subjects were labeled in vitro with [14C]linoleic acid, bound to albumin. The labeled cells were reincubated in autologous and homologous serum. The radioactivity present in the serum lipids and in the major phospholipid fractions of the red cell membranes was measured. Conclusions of this study are: 1) not all of the cystic fibrosis patients examined individually show an abnormal in vitro turnover of the red cell fatty acids, although they all presented abnormal fatty acid patterns for the red blood cell phospholipids, the platelet phospholipids, and the plasma lipids. 2) The in vitro abnormal fatty acid turnover occurs only in the incubations where red cells of cystic fibrosis patients are involved (in homologous and autologous serum) and not where red cells of healthy subjects are incubated in serum of cystic fibrosis patients. Consequently, the abnormal turnover is intrinsic to the red cells and is not induced by extrinsic serum factors.