[Ineffective granulopoiesis in pernicious anemia (author's transl)].

The mechanism of neutropenia was studied in 6 patients with pernicious anemia. While the peripheral blood of these patients disclosed neutropenia, the number of myeloid committed stem cells in the bone marrow was increased when compared with values obtained from 15 patients with undisturbed granulopoiesis. In 2 of 3 patients investigated, the number of circulating stem cells was also elevated. In 2 patients the number of stem cells was monitored during treatment with vitamin B12: A rapid decline of stem cells was observed, which was followed by an increase in mature granulocytes. These studies demonstrate an expanded stem cell pool, which is associated with ineffective granulopoiesis.