Hematological remission and long term hematological control of acute myeloblastic leukemia induced and maintained by granulocyte-colony stimulating factor (G-CSF) therapy

We describe a case of a patient with CD34+, TdT+, CD13-, CD33-, MPO- undifferentiated acute leukemia who refused chemotherapy and who achieved complete hematological remission 14 months after the diagnosis, during a short course of granulocyte-colony stimulating factor (G-CSF) for neutropenia and life threatening infection. Relapse occurred approximately one year later and G-CSF was reintroduced, being maintained for 4 months, at a dose and frequency adapted to maintain normal blood counts, a complete hematological remission being achieved again. Five months after withdrawing the G-CSF therapy a second relapse was observed; G-CSF was tried again with success, resulting in a very good hematological response that was sustained by G-CSF maintenance therapy. One year latter there was the need of increasing the doses of G-CSF in order to obtain the same hematological effect, at same time blast cells acquired a more mature CD34+, TdT-, CD13+, CD33-, MPO+ myeloid phenotype. Finally, the patient developed progressive neutropenia, anemia, thrombocytopenia and acute leukemia in spite of G-CSF therapy, dying 64 months after initial diagnosis (50 months after starting G-CSF therapy) with overt G-CSF resistant acute myeloblastic leukemia (AML), after failure of conventional induction chemotherapy.