IN-VIVO EFFECTS OF VARIOUS THERAPIES ON COMPLEMENT-SENSITIVE ERYTHROCYTES IN PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA

The percentage of complement-sensitive erythrocytes varies among patie nts with paroxysmal nocturnal hemoglobinuria (PNH) and is related to d isease severity. We examined the changes of complement-sensitive eryth rocytes following administration of androgens, prednisolone, dextran, and iron to 12 PNH patients using the complement lysis sensitivity tes t or flow cytometric analysis of decay accelerating factor and CD59/me mbrane attack complex-inhibitory factor expression for 11 years. Five untreated PNH patients were also studied as a control group. The compl ement-sensitive erythrocyte count remained almost constant in the cont rol group, while it increased in four out of five patients receiving a ndrogens. In addition, it decreased in two out of three patients recei ving prednisolone, increased in both patients treated with dextran, an d increased slightly in two of the three patients receiving iron thera py. Episodes of hemoglobinuria increased in three of the nine patients showing an increase of complement-sensitive erythrocytes, and decreas ed in four patients receiving prednisolone or dextran. A good response to treatment was clinically observed in four patients receiving andro gens, in one patient treated with prednisolone, and in one patient rec eiving dextran according to the scoring system. These findings suggest that PNH remains stable when the number of complement-sensitive eryth rocytes remains fairly constant, and that the PNH III erythrocyte coun t is especially related to the frequency of hemoglobinuria. Thus, it s eems to be important to determine the long-term effect of drug therapy on complement-sensitive erythrocytes to select the most appropriate t reatment.