f Acute Promyelocytic Leukemia with High White Cell Blood Counts.

Acute promyelocytic leukemia (APL) with WBC above 10 G/L has long been con even in the all-trans retinoic acid (ATRA) era, to carry a relatively poor prognosis (compared to APL with WBC below 10 G/L), due to increased early mortality and relapse. However, early deaths can to a large extent be avoided if specific measure referral to a specialized center, immediate onset of ATRA and chemotherapy, treatment of coagulopathy with adequate platelet transfusional support, and prevention and management of differentiation syndrome. Strategies to reduce relapse rate include chemotherapy reinforcement with cytarabine and/or arsenic trioxide during consolidation, prolonged maintenance treatment, especially with ATRA and low dose chemotherapy, and possibly, although this is debated, intrathecal prophylaxis to prevent central nervous system relapse. By applying those measures, outcomes of patients with high risk APL have considerably improved, and have become in many studies almost similar to those of standard risk APL patients. Introduction: Acute promyelocytic leukemia (APL) is a distinct type of acute myeloid leukemia (AML) characterized by specific morphology (M3 in the FAB classification), frequent association of a the t(15:17) translocation resulting in the fusion protein PML-RARα. The APL has a specific sensitivity to the differentiating properties of all-trans retinoic acid (ATRA) and the proapoptotic effect of arsenic trioxide (ATO), which have, in combination with anthracyline based chemotherapy, considerably improved its prognosis in the last 20 years. 1-6 WBC counts are generally low in APL, with only