Complete remission in a patient with hypoplastic acute lymphoblastic leukemia induced by granulocyte-colony-stimulating factor.

We report here a case of hypoplastic leukemia with T cell markers in whom complete remission was obtained with granulocyte-colony-stimulating factor (G-CSF) alone. A 23-year-old male was diagnosed with hypoplastic leukemia: Hb 2.6 g/dl, platelet count 29.0 x 10(9)/l after transfusion, WBC 2.9 x 10(9)/l, hypocellular bone marrow with 70.7% blasts. He was given G-CSF 300 micrograms/day by intravenous drip infusion without antileukemic agents for severe pneumonia. After the administration of G-CSF for 15 days, hematological examination and bone marrow findings had improved to normal, and complete remission was obtained. However, the patient relapsed 45 days after discontinuation of G-CSF. The characteristics of the relapsed leukemia cells were similar to those on admission: negative for myeloperoxidase and positive for T cell markers (CD2 and CD7). The possibilities for the differentiation of leukemic cells and the recovery of normal hematopoiesis with G-CSF are discussed.