Granulocyte-macrophage colony-stimulating factor (GM-CSF) treatment of clozapine-induced agranulocytosis: a case report.

Background: Granulocytopenia and agranulocytosis are severe side effects of clozapine therapy. Even if these side effects are detected early and if clozapine is discontinued, patients suffering from agranulocytosis are extremely endangered by infectious diseases for up to 3 to 4 weeks until hematologic recovery. Therefore, any treatment that reduces this critical time span would decrease the risks of clozapine treatment.
Method: The case of a patient in whom severe agranulocytosis developed after 7 weeks of clozapine treatment is presented.
Results: After clozapine discontinuation, treatment with granulocyte-macrophage colony-stimulating factor (GM-CSF), a glycoprotein that has been shown to stimulate the proliferation of precursor cells in the bone marrow and their differentiation into granulocytes and macrophages, was initiated. Under GM-CSF treatment, total granulocyte count rose from 63/cu mm to a value greater than 1500/cu mm within 5 days without complications or major side effects.
Conclusion: This case report suggests that treatment with GM-CSF may lower the risks associated with clozapine-induced agranulocytosis and therefore may indirectly improve the safety of clozapine therapy.