Primary and Secondary Myelofibrosis: Its Relationship to "PNH-like Defect"

Twenty-two patients with primary myelofibrosis and myeloid metaplasia (MMM) and ten patients with MMM secondary to carcinoma were studied for the relationship of MMM to "PNH-like defect." Laboratory measurements included Ham’s test, sucrose hemolysis test, sugar-water test, leukocyte alkaline phosphatase, haptoglobin, and urinary hemosiderin. The defects of the red cell membrane, as evidenced by acid and sucrose lysis tests, were limited to those with primary MMM and occurred in 54% of the cases. Another 10% showed decreased haptoglobin level, positive sugar-water test, and/or hemosiderinuria suggestive of the syndrome.