The percentage of
complement-sensitive erythrocytes varies among patients with
paroxysmal nocturnal hemoglobinuria (PNH) and is related to disease severity. We examined the changes of
complement-sensitive erythrocytes following administration of
androgens,
prednisolone,
dextran, and
iron to 12 PNH patients using the
complement lysis sensitivity test or flow cytometric analysis of
decay accelerating factor and CD59/
membrane attack complex-inhibitory factor expression for 11 years. Five untreated PNH patients were also studied as a control group. The
complement-sensitive erythrocyte count remained almost constant in the control group, while it increased in four out of five patients receiving
androgens. In addition, it decreased in two out of three patients receiving
prednisolone, increased in both patients treated with
dextran, and increased slightly in two of the three patients receiving
iron therapy. Episodes of
hemoglobinuria increased in three of the nine patients showing an increase of
complement-sensitive erythrocytes, and decreased in four patients receiving
prednisolone or
dextran. A good response to treatment was clinically observed in four patients receiving
androgens, in one patient treated with
prednisolone, and in one patient receiving
dextran according to the scoring system. These findings suggest that PNH remains stable when the number of
complement-sensitive erythrocytes remains fairly constant, and that the PNH III erythrocyte count is especially related to the frequency of
hemoglobinuria. Thus, it seems to be important to determine the long-term effect of
drug therapy on
complement-sensitive erythrocytes to select the most appropriate treatment.