Background. Platelets are an underappreciated factor in the classification of bleeding tendency of hemophilia patients. In this cross-sectional study, we have investigated platelet activation status and responsiveness in relation to residual FVIII activity and, within the severe (<1% residual FVIII activity) hemophilia patients, to annual FVIII consumption.
Design and Methods. Twenty-one mild-moderate hemophilia A patients, 13 severe hemophilia A patients and 21 healthy controls were included. Basal level of platelet activation and platelet responsiveness to activation and inhibition were determined by the measurement of platelet P-selectin expression and soluble platelet activation markers.
Results. Severe hemophilia A patients showed a higher percentage of activated platelets at baseline (15.9%) when compared to mild-moderate patients (8.2%, p 0.014) and controls (6.4%, p <0.001). Both mild-moderate and severe hemophilia A patients had higher levels of soluble platelet activation markers Platelet Factor 4 (PF4) (1.4 and 1.8 pg/106 platelets), CXCL7 (65.8 and 48.2 pg/106 platelets) and RANTES (12.8 and 9.5 pg/106 platelets), when compared to controls (PF4: 0.3 pg/106 platelets, p<0.001 and <0.001; CXCL7 20.0 pg/106 platelets, p<0.001 and <0.001; RANTES 4.5 pg/106 platelets, p<0.001 and =0.003, respectively). In support of these observations, we found clinical evidence that higher platelet P-selectin expression correlates with a lower FVIII consumption in patients with severe hemophilia (Spearman's r -0.65, p=0.043).
Conclusions. This study indicates that platelets of severe hemophilia A patients are in a pre-activated state and that this pre-activated state is associated with FVIII consumption.
- Received February 18, 2011.
- Accepted March 11, 2011.
- Copyright © 2011, Ferrata Storti Foundation