Glycosylphosphatidyl-inositol (GPI)-linked protein deficiency on the platelets of patients with aplastic anaemia and paroxysmal nocturnal haemoglobinuria: two distinct patterns correlating with expression on neutrophils.

Deficiencies in glycosylphosphatidyl-inositol (GPI)-linked proteins on erythrocytes and leucocytes in patients with paroxysmal nocturnal haemoglobinuria (PNH) are well known; however, expression on platelets in these patients is less well documented. We have studied CD55 and CD59 on the platelets of PNH and aplastic anaemia (AA) patients using flow cytometry. In all cases of PNH, CD55 and CD59 negative populations of platelets were detected with single or bimodal distribution and these results showed close correlation with the CD55 and CD59 patterns of neutrophils. Previous published studies have not demonstrated this distribution. We suggest that our findings may be due to the methodology used.