Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and rhG-CSF in the treatment of a child with severe chronic neutropenia.

Recombinant human granulocyte colony-stimulating factor (rhGCSF) has been widely and successfully used in treating childhood congenital or idiopathic neutropenia.' Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) has been less commonly and, in some patients in whom it failed, rhGCSF was able to restore normal granulocyte count? We report a case with a negative response to rhG-CSF and a positive one to rhGM-CSF. G.A. is a 6-year-old boy in whom chronic severe congenital neutropenia was diagnosed since the first days of life. He suffered from several recurrent bacterial infections requiring hospitalization and intravenous antibiotic administration. Bone marrow (BM) biopsy samples showed reduced myeloid lineage, normal erythroid, megakaryocytic and lymphoid series. BM aspirate smears confirmed the decrease of myeloid cells (myeloidlerythroid [ME] ratio = 0.5; normal values at matched age = 2.6) with no maturative arrest. The median absolute neutmphil count (ANC) until 2 + 6/12 years of life was 0.37 X 10yL. Chromosomal abnormalities, myelodysplasia, hematologic malignancy, aplastic anemia and presence of antineutrophil antibodies were excluded. At the age of 2 + 6/12 years the child was enrolled in the GCSF-8902 G-I2930 (Amgen, Thousand Oaks. CA) protocol, starting with a 5 pgkg/die dose subcutaneously. In absence of positive response, the dose was