Thrombotic events revisited in children with acute lymphoblastic leukemia: impact of concomitant Escherichia coli asparaginase/prednisone administration.

Recently published data suggest that the prothrombin G20210A variant, the TT677 methylenetetrahydrofolate reductase genotype, the factor V G1691A mutation, deficiencies of protein C, protein S, antithrombin, and elevated lipoprotein (a) concentrations were associated with venous thromboembolism in childhood patients treated according to the BFM protocol. To unravel the role of these prothrombotic risk factors and different treatment modalities, the present comparative study was performed in childhood leukemia patients of the same living population. Four hundred and twenty consecutively recruited leukemic children (BFM n=300; COALL n=120) were enrolled in this study with respect to the presence of prothrombotic risk factors and the occurrence of symptomatic venous thrombosis. No significant difference was found in the prevalence rates of thrombotic risk factors in the Caucasian populations studied. Symptomatic venous thromboembolism occurred in 11.6% of BFM patients compared with 2.5% in the COALL treatment group [odds ratio (OR)/95% confidence intervals (CI): 7.7/1.8-32.6; P=.005]. Including age, prothrombotic risk factors, central venous lines, treatment protocols, and anti-leukemic drugs in a logistic regression model, only the concomitant Escherichia coli asparaginase/prednisone administration in leukemic children suffering from a prothrombotic risk factor was found to increase the rate of thrombotic manifestations during leukemia treatment in patients of the same Caucasian origin (OR/95% CI: 34.5/4.39-271.42; P=.0008). Based on the data presented here, we suggest the use of prednisone and E. coli asparaginase concomitantly administered in a leukemic patient suffering from a prothrombotic risk factor to be responsible for the onset of venous thrombosis in the majority of cases.