Summary
Platelet function abnormalities have been described in some patients with hemophilia. This study reports measurements of plasma β-thromboglobulin (BTG) and platelet factor 4 (PF4), sensitive and specific markers of platelet α-granule release in 72 hemophiliacs. Patients were studied on multiple occasions depending on their clinical condition and the treatment given. Stable patients without recent bleeding showed significantly elevated BTG levels: 29.72 ± 12.77 ng/ml, control 23.22 ± 8.22, p = 0.006. This appears to be independent of the presence of liver disease, human immune deficiency virus infection (HIV) and the acquired immune deficiency syndrome (AIDS). The increased BTG level seems to correlate with the severity of the disease as reflected by the frequency of bleeding and the quantity of factor concentrate used but not with plasma factor VIII or IX procoagulant activity. Patients who have experienced recent bleeding showed a marked rise in BTG level (77.26 ± 51.37 ng/ml, p = 0.0002), indicating enhanced in vivo platelet activation. These observations suggest that enhanced platelet release in hemophilia most likely reflects sustained activation of hemostasis secondary to frequent bleeding characteristic of the severe form of the disease.
Keywords
Platelet release - Hemophilia
