Paroxysmal nocturnal hemoglobinuria with myelofibrosis: progression to acute myeloblastic leukemia.

A 58-year-old male was diagnosed as having paroxysmal nocturnal hemoglobinuria (PNH) with myelofibrosis in 1984. The administration of hydroxyurea and low dose splenic irradiation were initiated for abdominal distention due to splenomegaly in 1987. In May 1990 the patient developed smouldering acute myeloblastic leukemia (AML); and the blasts proliferated in response to G-CSF administered for refractory pneumonia. The patient died of pneumonia and pleural involvement of leukemia in September 1990. FACS analysis of the blasts using anti-decay accelerating factor (DAF) (CD55) and CD59 (membrane attack complex inhibition factor: MACIF) monoclonal antibodies demonstrated that 25.5% and/or 87.3% of the blasts were negative for DAF or CD59 respectively. There is the earlier evidence that about 90% leukemic myeloblasts from non-PNH AML patients are positive for DAF, and nearly 100% of non-PNH neutrophils have been shown to be positive for both DAF and CD59. Our data suggest that the leukemic blasts from this patient may have derived from the PNH clone.