Acute Promyelocytic Leukemia with Fibrinogen and Factor V Deficiencies

1. Two patients with acute promyelocytic leukemia (APL) are reported.Many of the promyelocytes were atypical. Of the 57 patients with thisdisorder in the literature, only three survived more than 4 months. Ourpatients underwent complete remission on 6-mercaptopurine, and survived8 and 14 months, respectively.

2. Coagulation abnormalities in these two patients were thrombocytopenia;fibrinogen and factor V deficiencies; and, in one, prothrombin deficiency.These defects disappeared with remission, then reappeared terminally. Incontrast to most previous reports, no increased fibrinolytic activity was foundin their blood. Infused fibrinogen disappeared abnormally rapidly from theblood of one patient; this was not affected by simultaneous heparin administration, and no thrombi were seen at autopsy.

3. Fibrinogen, factor V, and prothrombin were assayed in 86 patients withother forms of leukemia before treatment or in relapse. Fibrinogen deficiencywas found in none; prothrombin and/or factor V deficiency in eight. Threeof these had acute myeloblastic, three acute myelomonoblastic, and twochronic myelocytic leukemia.

4. The characteristic cellular morphology, combined with the usual findingof fibrinogen and factor V deficiencies, makes for a distinct differentiation ofAPL from other forms of leukemia.

Submitted on July 16, 1963 Accepted on December 23, 1963