[Granulopoietic effects of lentinan in mice: effects on GM-CFC and 5-FU-induced leukopenia].

C57BL mice were injected intravenously with an antitumor immunopotentiating polysaccharide, lentinan, to assess its effect on granulopoiesis in normal mice as well as its ability to enhance the recovery from leukopenia induced by 5-fluorouracil (5-FU). Lentinan increased neutrophils and monocytes in peripheral blood as well as granulocyte-macrophage progenitor cells (GM-CFC) in spleen and bone marrow. Administration of 5-FU induced a significant decrease in GM-CFC from day 1 to day 6, and thereafter the number of GM-CFC rebounded. The administration of 5-FU also suppressed white blood cells such as neutrophils, monocytes and lymphocytes. Injection of lentinan one day after 5-FU resulted in prompt restoration of the leukopenia through the recovery of neutrophils, monocytes and lymphocytes as well as prompt and marked rebound of GM-CFC. These results suggest that lentinan may contribute to the recovery from some of the hematopoietic depression in clinical chemoimmunotherapy.