title: The effect of continuous G-CSF application in human cyclic neutropenia: a model analysis.
abstract: Human cyclic neutropenia (CN) is a rare haematological disorder characterized by oscillations of blood neutrophils at subnormal levels with a stable period of approximately 21 d. During the phase of severe neutropenia (neutrophils < 250 cells/microliters), which last 4-10 d, the patients are endangered by serious infections. Several authors report that continuous G-CSF application can elevate the blood neutrophils to such a level that the risk of infections is significantly reduced. Although the characteristic cycles are not eliminated by G-CSF, the period of the oscillations is shortened to 12-14 d. Based on a previously proposed computer-simulation model of human CN, the effects of continuous G-CSF application on CN are studied. It is shown how the known different cell-kinetic effects of G-CSF on granulopoiesis explain the clinical data in CN. The reduced length of the cycles emerges as a result of the transit time reduction of the post-mitotic granulopoietic cells by G-CSF. The measured increase of the neutrophil maxima is reproduced by the additional mitoses of the immature granulopoietic bone marrow cells induced by G-CSF. The slight elevation of the neutrophil nadirs can be attributed to a weak effect of G-CSF on the assumed underlying defect in CN (an abnormally small variance of the granulopoietic bone-marrow transit time).
authors.affiliation: Clinic I for Internal Medicine, University of Cologne, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schmitz
authors.forename: H
authors.initials: H
authors.lastname: Franke
authors.forename: H E
authors.initials: HE
authors.lastname: Wichmann
authors.forename: V
authors.initials: V
authors.lastname: Diehl
mesh_terms: D002453:Cell Cycle; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage*; D006410:Hematopoiesis; D006801:Humans; D008954:Models, Biological; D009503:Neutropenia / Q000628:therapy*; D010507:Periodicity; D013997:Time Factors
chemical_list: D016179:Granulocyte Colony-Stimulating Factor