PO-26 Coagulation activation in myeloid leukemia: the role of integrin CD11b, leukocytosis, blast cells and promyelocytes

Background: Coagulation activation is a prethrombotic state of venous thromboembolism, the second leading cause of death in cancer patients. At present, there are few reports in the literatures on coagulation activation in myeloid leukemia patients. Integrin CD11b/CD18 is an adhesion molecules expressed on leukocytes which mediate the interaction of leukocytes with platelets and endothelial cells and has important role in endothelial activation by myeloblasts. On the other hand, the high leukocyte count which is specific for myeloid leukemia, can modulate endothelial cells. The study was intended to determine the expression of CD11b in myeloid leukemia with high leukocyte count as well as myeloblasts (and promyelocytes) as risk factors for coagulation activation. Objectives: This study was implemented to determine the role of CD11bin coagulation activation (increased levels of F1+2) in myeloid leukemia, compared to leukocyte counts and myeloblast + promyelocytes. Materials and Methods: This was a cross sectional comparative study at the Division of Hematology and Medical Oncology, Dept. of Internal Medicine, Univ. of Indonesia/Cipto Mangunkusumo Hospital from January2008 until February 2009. The subjects were myeloid leukemic patients(AML and CML). The expression of CD11b was measured by flowcytometry method using monoclonal antibodies from Becton-Dickinson and Facscalibur machine, the level of F1+2 was measured using ELISA kit of Enzygost F1+2 (Siemens) and Siemens ELISA Processor-III. Results: There were 80 subjects (25 AML patients, 14 CML patients and41 controls) aged 17–71 years. The OR of CD11b >91.5% to the increased levels of F1+2 was 7.1 (81% risk for coagulation activation). The adjusted-OR of leukocyte 50,000–100,000/mL and leukocyte >100,000/mL were 13.4 and11.2. The adjusted-OR of myeloblasts + promyelocyte >5% was 9.6 (91% risk for coagulation activation). Conclusions: Myeloid leukemic patients have higher risk for thrombotic complications if they have leukocyte counts >50,000/uL, myeloblasts +promyelocytes >5% and/or expression of CD11b >91.5%.