Erythrocyte characteristics in childhood acute leukemia.

Children with acute leukemia often have erythrocytes with "fetal-like" features. To examine the relationship of the type and phase of the leukemia to this observation, we studied 39 children with newly diagnosed acute lymphocytic leukemia (ALL) and 5 with acute nonlymphocytic leukemia (ANLL). In addition, 22 patients were evaluated during chemotherapy, 3 off therapy, and 12 at the time of relapse. Macrocytosis and/or anisocytosis was noted in 70% of patients with ALL at the time of first diagnosis, 80% of patients with new ANLL, and greater than 90% of patients with ALL while on treatment. F cells were increased in 25% of ALL and 80% of ANLL at diagnosis and in 60% of ALL during chemotherapy. Hb F levels were elevated in 8, 40, and 30% of these groups, respectively. Nonleukemic controls for chemotherapy (six patients with osteogenic sarcoma) all had macrocytosis and/or anisocytosis, and 80% had increased F cell proportions. Features at relapse on chemotherapy were similar to those during treated remissions. Abnormal RBCs are more frequent at the time of diagnosis in ANLL, in which they may belong to the malignant clone, than in ALL, in which stress erythropoiesis and/or leukemic factors may be contributory. During chemotherapy, drug-related erythrocyte changes are added to those of leukemia itself. Thus, leukemia, chemotherapy, and the combination lead to erythrocytes with fetal-like features.