evaluating fk506 (tacrolimus) effects on cord blood hematopoietic progenitor cells

introduction: umbilical cord blood is a rich source of hematopoietic cells and can be used in the clinical setting for hematopoietic cell transplantation in graft versus host disease (gvhd). a number of different drugs have been used as prophylaxis against gvhd including corticosteroids, cyclosporine a (cy a) and fk506. in this study, the in vitro effects of fk506 on cord blood mononuclear cells were assessed. material and methods: after cord blood collection and separation of mononuclear cells, the viability of them was assessed. then, following 7-day liquid culture in the dmem medium and in the presence of early acting growth factors such as scf, fl, tpo and il-6 and different doses of fk506, cells were counted and myeloid/erythroid ratios were determined. furthermore, the percentage of cd34+ cells was assessed by flow cytometry. in this study, clonogenic assay was carried out in two stages (before and after 7- day liquid culture). results: under the mentioned culture conditions, cell counts and m/e ratios did not change in comparison with control (p=0.126 and p=0.819, respectively). the percentage of cd34+ cells rose considerably (p=0.018). compared with control, colony numbers decreased in the first stage (p=0.000), whereas the number of colonies did not change in the second (p=0.109). conclusion: our results demonstrate that fk506 is not only an immunosuppressive agent but also has stimulating effects on expansion and clonogenesity of cord blood mononuclear cells. but in has no effect on differentiation of these cells.