1. ¹Department of Cellular Biotechnology and Hematology, University La Sapienza, Rome, Italy
2. ²Medical Oncology and Haematology, Campus Bio-Medico University, Rome, Italy
3. ³Department of Hematology, Regina Elena Institute, Rome, Italy
4. ⁴Department of Biopathology, University of Tor Vergata, Rome, Italy

Correspondence: Dr M Breccia, Department of Cellular Biotechnology and Hematology, University La Sapienza, Via Benevento 6, Roma, Rome 00161, Italy. E-mail: breccia@bce.uniroma1.it

Received 24 May 2006; Revised 26 July 2006; Accepted 28 July 2006; Published online 24 August 2006.

Abstract

Although the occurrence of thrombosis in acute promyelocytic leukemia (APL) has been reported during retinoic acid treatment, no studies carried out in large clinical cohorts have specifically addressed this issue. We analyzed 124 APL patients treated with the all-trans retinoic acid and idarubicin protocol and compared clinico-biologic characteristics of 11 patients who developed thrombosis with those of 113 patients who had no thrombosis. In seven patients, the events were recorded during induction, whereas in four patients deep vein thrombosis occurred in the post-induction phase. Comparison of clinico-biological characteristics of patients with and without thrombosis revealed in the former group higher median white blood cell (WBC) count (17 10⁹/l, range 1.2–56, P=0.002), prevalence of the bcr3 transcript type (72 vs 48%, P=0.01), of FLT3-ITD (64 vs 28%, P=0.02), CD2 (P=0.0001) and CD15 (P=0.01) expression. No correlation was found with sex, age, French-American-British subtype, all-trans-retinoic acid syndrome or with thrombophilic state that was investigated in 5/11 patients. Our findings suggest that, in APL patients consistent biologic features of leukemia cells may predict increased risk of developing thrombosis.