An acquired form of Bernard Soulier syndrome associated with acute myeloid leukemia.

Objective: To investigate glycoprotein-1b (GP-1b) expression on platelets from patients with acute myeloid leukemia (AML).

Methods: Purified platelets, obtained from AML-patients and normal control subjects, were examined for surface membrane GP1b-expression by flow cytometry and GP1b-mediated aggregation responses by aggregometry. The level of elastase in plasma from patients and controls was measured by enzymed-linked immunosorbent assay. The whole of this work was carried out at the University of Liverpool, Liverpool, United Kingdom during the period of 1994-2001.

Results: Platelets from the majority of AML-patients showed reduced GP1b-expression and reduced GP1b-mediated aggregation responses. Reduction in platelet GP1b-expression was associated with increased plasma elastase levels.

Conclusion: The present study suggests that elastase, released from leukemic blasts, degrades platelet GP1b, resulting in dysfunctional circulating platelets in AML-patients. These results could explain the bleeding disorders observed in these patients.