The in Vitro Lysis of the Red Cells of Paroxysmal Nocturnal Haemoglobinuria by the Serum of Patients with Cirrhosis of the Liver

Summary: The complement (c′) titre, the concentration of the third component of C’ (c′3) and the capacity of sera to lyse PNH cells in the acidified‐serum test and the sugar‐haemolysis test have been determined on the sera obtained from 100 healthy subjects and 103 patients with cirrhosis of the liver. The lytic capacity of normal sera for PNH cells is not correlated with the serum's C'titre or c′3 concentration. With cirrhotic sera, however, a significant correlation was found between c′3 concentration and PNH haemolytic capacity, especially in the sugar‐haemolysis test. It is concluded that, under certain conditions, c′3 can be rate‐limiting in PNH cell lysis in vitro.