G-CSF plasma levels in clozapine-induced neutropenia.
BACKGROUND
Clinical reports emphasize the therapeutic usefulness of granulocyte colony-stimulating factor (G-CSF) in clozapine-induced granulocytopenia. Only sparse information exists, however, on the natural course of endogenous G-CSF plasma levels in this condition.


METHODS
We monitored G-CSF and white blood cell (WBC) counts in a 73-year-old patient who developed granulocytopenia while being treated with clozapine for schizoaffective disorder. Clozapine treatment was discontinued immediately, and G-CSF serum levels were determined repeatedly during the clinical course.


RESULTS
Whereas WBC counts increased again within 6 days after discontinuation of clozapine, G-CSF level decreased significantly within the same period. The rapid decrease of endogenous G-CSF levels paralleled by a normalization of neutrophil count was interpreted as the result of an intact regulatory mechanism of granulocytopoesis. Therefore G-CSF therapy was not initiated. Owing to lack of therapeutic alternatives, it was decided to reintroduce clozapine. G-CSF levels decreased further, accompanied by an increase of WBCs, indicating stable bone marrow functioning.


CONCLUSIONS
Based on this observation, we assume that the course of G-CSF and WBC counts indicated an abortive form of toxic bone marrow damage with subsequent recovery. We conclude that monitoring of G-CSF levels may serve as a useful tool in the follow-up of patients in whom clozapine-induced bone marrow damage is suspected.
Jauss
M
M
Department of Psychiatry, Section of Geriatric Psychiatry, University of Heidelberg, Heidelberg, Germany.
Pantel
J
J
Werle
E
E
Schröder
J
J
D000368:Aged; D000380:Agranulocytosis / Q000139:chemically induced; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000097:blood*; D006801:Humans; D007958:Leukocyte Count; D009503:Neutropenia / Q000097:blood / Q000139:chemically induced*; D011618:Psychotic Disorders / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D012074:Remission Induction; D013997:Time Factors; D016896:Treatment Outcome
D014150:Antipsychotic Agents; D016179:Granulocyte Colony-Stimulating Factor; D003024:Clozapine