Effect of Orally Administered Heat-Killed Enterococcus faecalis FK-23 Preparation on Leukopenia in Mice Treated with Cyclophosphamide

Abstract

Cyclophosphamide (CY) treated mice were orally administered heat-killed Enterococcus faecalis FK-23 preparation (FK-23) to define the effect of FK-23 on leukopenia associated with chemotherapy. FK-23 had no inhibiting effect on CY induced leukopenia, whereas it augmented leukocyte reconstitution in CY-treated mice. The percentage of neutrophils increased in the mice orally given FK-23. Furthermore, an increase in a myeloid/erythroid ratio and neutrophilic lineages was found in bone marrow of FK-23 treated mice. These findings suggest that FK-23 may have a potent effect on the augmentation of leukocyte reconstituting capacity in patients receiving chemotherapy.