Production of paroxysmal nocturnal haemoglobinuria-like red cells by reducing and oxidizing agents.

Abstract

Summary. Normal red cells incubated with high concentrations of compounds containing sulphydryl groups are known to develop several characteristics of red cells obtained from patients with paroxysmal nocturnal haemoglobinuria (PNH). These include positive acid and sucrose haemolysis tests and a decline in acetylcholinesterase (AChE) activity. The present studies demonstrate that incubation of normal red cells with the non‐sulphydryl reducing agent sodium borohydride also results in the production of PNH‐like characteristics. Evaluation of this phenomenon utilizing the sulphydryl agents glutathione (GSH) and dithiothreitol (DTT) reveals that the transformation is not dependent upon the presence of oxygen, is not associated with a significant decline in red cell vitamin E levels, and is not observed when GSH is rapidly oxidized by azoester. It appears that the most likely mechanism for the formation of PNH‐like red cells under these conditions is through the reduction of cell membrane disulphide groups.Production of a positive sucrose and acid haemolysis test as well as a decline in AChE activity was also observed in two experimental systems which produce oxidative free radical damage to the red cell membrane: gassing of normal red cells with ozone, and irradiation of red cells from patients with erythropoietic protoporphyria with 400 nm light.