Growth of bone marrow CFU-GM in a case of cyclical neutropenia. Preliminary report.

We studied bone marrow CFU-GM growth behaviour of a 9-year-old male child with cyclic neutropenia. The cultures were performed on day 0 and on day 13 of cyclic oscillation, in order to study some correspondences between CFU-GM culture parameters and the phases of a whole cyclic oscillation "in vivo". We explored the CFU-GM growth under three different conditions of GM-CSA production: a) standard source of CSA; b) endogenous GM-CSA assay; c) GM-CSA-gamma-globulin assay. At both observation times the endogenous GM-CSA assay produced more aggregates than the baseline culture. The GM-CSA-gamma-globulin assay partly corrected the growth increase, produced by endogenous assay. At time 0, at the nadir of peripheral blood neutrophils, there was a balance between the number of aggregates, appeared early in culture and early degenerated, and those appeared late. From progenitor cells culture performed on day 13 of cycle, a week before the zenith of neutrophils in vivo, we obtained an increase in aggregates, which appeared late. The values of CFU-GM grown from the culture performed on day 13 reached higher levels than the ones performed on day 0. The CFU-GM growth behaviour shows that in our case with cyclic neutropenia there is no defect in progenitor cells, while on the contrary there is an increase in CSA production.