DECAY-ACCELERATING-FACTOR-DEFICIENT ERYTHROCYTES DURING THE LONG-TERMCLINICAL COURSE OF PATIENTS WITH PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA

We performed long-term follow-up studies of 5 patients with paroxysmal nocturnal hemoglobinuria (PNH). The percentages of decay-accelerating -factor (DAF)-deficient erythrocytes were almost stable or slowly incr eased during the 2-4 years' observation periods when the effects of tr eatment with drugs or blood transfusion and pregnancy were excluded. H owever, a tendency of increase in the percentages of DAF-deficient ery throcytes was observed along with the duration of the disease. Our fin dings suggest that the growth advantage of PNH clones beyond the norma l hematopoiesis may be different from the other clonal stem cell disor ders.