Transmembrane cation fluxes and fatty acid composition of erythrocytes in psoriatic patients

Cation transport systems and lipid composition of erythrocyte membrane were studied in 27 psoriatic patients and in 34 healthy individuals. Whereas intracellular Na and K content, Na- and K-passive permeability and Li-Na countertransport of psoriatics did not show any statistical difference from normals, the Na/K ATPase pump activity was significantly higher and Na-K cotransport was significantly lower. Membrane lipid composition of psoriatics was different from normals: an increase in arachidonic acid and in unsaturated (poly- and total unsaturated) fatty acid content was found. A positive correlation was demonstrated between unsaturated/saturated fatty acid ratio and Na/K ATPase pump activity. These results demonstrate an alteration of erythrocyte Na/K ATPase pump and Na-K cotransport in psoriasis. These alterations of cation transport are associated with a perturbation of membrane fatty acid composition which appears a widespread phenomenon in cells of psoriatic patients.