Cystic fibrosis: normal volumes of red cells. Model experiments on the pathomechanism of the disease.

Normal values of mean cell volume (M.C.V.) and of distribution of single cell volumes (S.C.V.) have been observed in erythrocytes of patients with cystic fibrosis using an electronical particle-volume analyzer (sheath flow detector). From these results a strong defect in red cell salt transport seems improbable. Valinomucin induces shrinking (by increase of K+ permeability) and gramicidin D induces swelling (by increase of Na+ permeability) of normal erythrocytes. Addition of C.F. sweat to normal erythrocytes induces no volume change. From this result no influence of the "C.F. factor" on passive ion permeability is concluded.