Prediction of haemorrhage in the early stage of acute myeloid leukaemia by flow cytometric analysis of platelet function.

Haemorrhage is often responsible for the lethal course of acute myeloid leukaemia (AML). Previously, multiple platelet function defects were identified by flow cytometric analysis of platelet activation markers in AML. The role of flow cytometric analysis of platelet function in characterization of prognostic markers of haemorrhage in AML patients has not been well elucidated. The objective of this prospective study was to analyse platelet function in 50 AML patients at diagnosis and to compare results with clinical bleeding score, graded by common toxicity criteria. Platelet activation markers CD62P, CD42b, CD63 and PAC-1 were analysed following in vitro activation by thrombin receptor activating peptide. The following plasma haemostasis parameters were measured: soluble P-selectin, activated partial thromboplastin time, thrombin time, prothrombin time, D-dimer, fibrinogen, and von Willebrand factor antigen. In a multivariate analysis, P-selectin (CD62P) <36 molecules of equivalent soluble fluorochrome x 10(3) (P < 0.0015) and platelet count <40 x 10(9)/l (P = 0.01) were significant predictors of haemorrhage at diagnosis. Haemorrhage at diagnosis predicted grade 3-4 haemorrhage in the first 28 d following diagnosis (P = 0.018). The presented results indicate that low P-selectin is a prognostic marker of haemorrhage in AML.