Membrane Abnormalities of Paroxysmal Nocturnal Hemoglobinuria (PNH) Red Cells and PNH-like Red Cells

Abstract

Membrane properties of paroxysmal nocturnal hemoglobinuria (PNH) and PNH-like red cells, i. e. normal red cells treated with either 2-amino-ethylisothiouronium bromide (AET) or reduced glutathione (GSH), were compared and the following results were obtained. Osmotic fragility was normal in PNH and GSH-treated red cells, but was markedly increased in AET-treated red cells. ²²Na⁺ uptake was strikingly increased in AET-treated red cells, slightly increased in GSH-treated red cells and nearly normal in PNH red cells. The effect of p-hydroxymercuribenzoate (PHMB) on ²²Na⁺ uptake was more pronounced in PNH red cells than in AET-treated or GSH-treated red cells. The amount of membrane proteins extracted by sulfhydryl inhibitors, N-ethylmaleimide (NEM) or PHMB, was significantly reduced in PNH red cells but was not decreased in PNH-like red cells. Sulfhydryl content of the membrane was reduced in AET-treated red cells and GSH-treated red cells but nearly normal in PNH red cells. The reduction in sulfhydryl content in these PNH-like red cells were attributed to the decrease of free sulfhydryl groups on the outer surface of the membrane. AET and GSH are considered to alter the membrane structure of normal red cells by acting only on the outer surface of the membrane, producing PNH-like character-istics.