Hemostatic Disorder

Therapeutic plasmapheresis causes changes in haemostasis by purifying many of the circulating factors involved. Few reliable data are available on these changes and most studies are limited to coagulation factor assays before and after the session, with little data documenting the kinetics of regeneration of these factors. It is recognized that haemostasis disorders caused by therapeutic apheresis must be corrected in cases of active bleeding. However the methods of correcting these disorders are debatable. Finally, it is unclear when changes in haemostasis associated with coagulation factor deficiency should be corrected. Haemostasis is probably not based solely on the level of blood fibrinogen, but it is most often its threshold that is used to trigger replacement therapy to prevent a supposed risk of haemorrhage. No studies are available on the kinetics of haemostasis disorders and the risk of haemorrhage following a therapeutic plasmapheresis session, according to session type and fibrinogen level at the end of the session. The hypothesis of this research is that the link between fibrinogen level and thrombin generation capacity, post therapeutic plasmapheresis, will enable us to better assess the risk of haemorrhage and propose preventive measures.

The goal of this study is to investigate the hemostatic balance in children with acute lymphoblastic leukaemia (ALL) treated according to the ALLTogether1 protocol with focus on the early treatment period including concomitant use of steroids and asparaginase. The investigators aim to determine if complement proteins or microparticles can be used as clinically relevant predictive or diagnostic biomarkers for thrombosis and if global hemostatic assays can predict bleeding or thrombosis. Characterization of proteins connected to hemostasis before and during ALL treatment may provide pathophysiological insights regarding ALL- and treatment related coagulopathy. The ultimate goal of the study is to minimize the morbidity and mortality related to thrombosis and bleeding complications in children with ALL. Several pediatric oncology centers in Sweden will be participating in this study, which will enroll approximately 100 pediatric patients.