Hemostatic abnormalities in acute promyelocytic leukemia: clinical implications and mechanisms.

Purpose of review: Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia. The long-term prognosis for APL is generally more favorable than for other types of acute leukemia due to the use of differentiation therapies. However, early hemorrhagic death remains a significant clinical challenge in APL patients.

Recent findings: Real-world studies reveal that the rate of early hemorrhagic death remains high (10-30%) in APL patients in the era of differentiation therapy. APL patients have systemic hemostatic changes including activation of coagulation followed by consumption of coagulation factors, hyperfibrinolysis, and severe thrombocytopenia. Our study found that tissue factor contributes to a bleeding phenotype in mouse models of APL. In-vitro studies suggest that there may be direct or indirect interaction between APL cells and brain endothelial cells.

Summary: Predictors of hemorrhagic death in APL are only partially understood. The associations between bleeding and hyperfibrinolysis or thrombocytopenia in APL need to be determined. The interaction between APL cells and brain endothelial cells need to be determined in vivo.