Serum granulocyte colony-stimulating factor levels in patients with chronic neutropenia of childhood: modulation of G-CSF levels by myeloid precursorcell mass

The serum G-CSF levels of eight patients with severe congenital neutropenia (SCN) were found to be significantly higher than those of 22 patients with chronic benign neutropenia (CBN). The relative number of cells expressing the G-CSF receptor in light density bone marrow cells (LDBMC) was lower in patients with SCN than in patients with CBN or in normal subjects. When rec ombinant human G-CSF was incubated with LDBMC, G-CSF levels were decreased by LDBMC from normal subjects and CBN patients, but not by those from SCN p atients, Serum G-CSF concentrations, which are affected by mature neutrophi ls, may also be modulated by myeloid precursor cells in the bone marrow.