Granulocyte and granulocyte-macrophage colony-stimulating factors for treatment of neutropenia in glycogen storage disease type Ib

Two children with glycogen storage disease type Ib associated with numerous recurrent bacterial infections as a result of neutropenia and neutrophil dysfunction were treated with recombinant human granulocyte colony-stimulating factor (G-CSF). One of the two patients was previously treated with recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF); therapy had to be discontinued because of severe local side effects. Both colony-stimulating factors at dosages of 3 and 8 μg/kg/per day, respectively, increased the average neutrophil counts from less than 300 cells/μl to more than 1200 cells/μl. Two subpopulations of neutrophils could be identified by their capacity to produce H₂O₂: one subpopulation generated H₂O₂ normally and a second was defective in H₂O₂ production. The doses of G-CSF effectively enhanced and maintained that subpopulation of neutrophils which produced normal amounts of H₂O₂. Moreover, these colony-stimulating factor-induced neutrophils demonstrated effective phagocytosis of zymosan particles and killing of staphylococci. Chemotaxis was decreased and could not be normalized by treatment with G-CSF. We conclude that maintenance treatment with G-CSF improved the quality of life in both patients: The number and severity of bacterial infections decreased markedly during treatment. Long-term treatment with G-CSF (12 and 10 months, respectively) was well tolerated, and no adverse clinical events were observed.