[Granulocyte progenitor cells (CFC) culture in the adult chronic idiopathic neutropenia. A study of 12 cases (author's transl)].

Granulocyte progenitors (CFC) from 12 patients with idiopathic neutropenia were cultured in vitro and followed, in some cases, for several months. The results were similar whatever the degree of neutropenia and in the presence or absence of medullary hypoplasia. The medullary concentration of CFC was always clearly depressed, which correlated with a very low total number of CFC. In every case, when the cloning efficiency was low, there were few CFC per 10(5) metamyelocytes plated, which suggests an increase in mitotic amplification between the progenitor and the mature granulocytes. When circulating CFC were cultured, there was little or no growth, confirming the paucity of CFC in the host. No patient had an increase in cloning efficiency in marrow or blood that might have suggested ineffective granulopoiesis. In four patients, stimulatory or inhibitory activity in serum was studied; one serum was stimulatory, another, on two occasions, inhibitory. Possible machanisms for these results and their prognostic value are discussed.