Developmental patterns of granulocyte-monocyte and megakaryocyte lineages from cord and peripheral blood СD34+ cells

Abstract

The 6-days expansion of cord blood (CB) and mobilized peripheral blood (PB) CD34+ cells in co-culture with BM MSCs with addition of SCF, Flt3 ligand and TPO was performed. Fold expansion of CB cells was higher: 33 (23-42) for CB nucleated cells (TNC) vs 13 (11- 16) for PB TNC (p=0,004) and 15 (7-18) for CB CD34+ cells vs. 9 (7-11) for PB CD34+ cells (p=0,013). The mean fold expansion of CFU-E, BFU-E, CFU-G, CFU-GEMM cord blood was comparable to TNC fold increase. The high production of CFU-M and CFU-GM after the CB expansion is a distinctive difference of CB myelopoiesis, in contrast to PB cells (130 (37- 175) vs. 28 (4-62), p = 0,003; 44 (11-218) vs. 10 (2-37), p = 0,025). CB CFU-Mk fold expansion was lower than expected and was the same as PB CFU-Mk (19 (9-20) vs. 20 (5-49), p = 0,7). These data is consistent with ineffective counteraction of chemotherapy-induced thrombocytopenia by transplantation of expanded CB. Different CD34 expression on CB and PB megakaryocyte progenitors was observed. Ontogenically related myelopoiesis of CB and PB cells leads to different proliferative responses to cultural stimuli. Despite the same cultural conditions, only in the CB culture there was a redistribution of CFU proportions: a significant increase of monocyte-containing colonies (CFU-M and CFU-GM) and inhibition of the megakaryocytic lineage.