Susceptibility to autoxidation of lipids of paroxysmal nocturnal hemoglobinuria (PNH)-like red cells.

The susceptibility to autoxidation of red cell lipids was studied before and after transformation of normal red cells to PNH-like erythrocytes. The transformation was effected by treatment of the red cells with the sulfydryl compounds D-penicillamine (DP) and N-acetyl-L-cysteine (NAC). The autoxidation was induced by incubating the cells with H2O2 and was estimated by measuring the generated malonyl dialdehyde. The susceptibility to autoxidation was significantly higher in DP-treated cells, while the opposite was true for NAC-treated cells. However, both DP- and NAC-treated cells showed a similar sensitivity to lysis by acid serum and about the same degree of acetylcholinesterase (AChE) activity decrease, thus indicating that the susceptibility to autoxidation of lipids is not involved in the determination of complement sensitivity or in the AChE activity decrease of the sulfydryl-treated cells. Finally, since, as evidenced from most of the reported cases in the literature, increased susceptibility to autoxidation is a feature of PNH cells, it seems reasonable to suggest that DP-treated cells should be used in preference to NAC-treated cells as a laboratory substitute for PNH cells.