The synergistic effect of thrombopoietin in erythropoiesis with erythropoietin and/or IL-3 and myelopoiesis with G-CSF or IL-3 from umbilical cord blood cells of full-term neonates

The authors sought to determine whether recombinant human thrombopoietin (T PO) acts synergistically with other cytokines on burst-forming unit-erythro id (BFU-E)-derived and colony-forming unit-granulocyte/macrophage (CFU-GM)- derived colony formations from cord blood. Cord blood nonadherent mononucle ar cells (MNC)from normal full-term neonates were cultured in a methylcellu lose system. When cultured with 5 x 10(4) MNC/mL, erythropoietin (EPO) 2 U/ mL, interleukin-3 (IL-3) 50 ng/mL, and/or TPO 400 ng/mL (experiment 1), the addition of TPO to EPO gave rise to more BFU-E-derived colonies (p = .002) . The addition of TPO to EPO + IL-3 gave rise to mote BFU-E-derived colonie s (p = .006) also. TPO synergizes erythropoiesis from cord blood. When cult ured with IL-3 50 ng/ML, granulocyte colony-stimulating factor (G-CSF) 25 n g/mL, and/ or TPO 400 ng/mL, the addition of TPO to IL-3 gave rise to more CFU-GM-derived colonies (p = .002). The addition of TPO to G-CSF, gave rise to more CFU-GM-derived colonies (p = .002) also, TPO synergizes myelopoies is from cord blood. Thus, TPO has synergistic effects on both erythropoiesi s and myelopoiesis from cord blood. In the identical conditions of culture, cord blood had significantly greater BFU-E-derived or CFU-GM-derived colon y formation than bone marrow (in a previous report by the authors) did. Whe n cultured under conditions similar to those ofexperiment 1, but with 1 x 1 0(4) cord blood MNC/mL and TPO 100 ng/mL (experiment 2), results similar to those in the experiment I also revealed that TPO has synergistic effects o n erythropoiesis and myelopoiesis from card blood. In every individual assa y, the numbers of BFU-E-derived or CFU-GM-derived colonies in experiment 1 were significantly higher than those in experiment 2.