The regulatory role of Hyper-IL-6 in the differentiation of myeloid and erythroid progenitors derived from human cord blood

This study was designed to investigate the regulatory role of soluble interleukin-6 receptor (sIL-6R) and interleukin-6 (IL-6) fusion protein (Hyper-IL-6) in the differentiation of human myeloid and erythroid progenitors by a serum-free liquid suspension culture system, using the human cord blood-derived CD34+CD38− cells as a target. We found that Hyper-IL-6 promoted the generation of CD15+ granulocytic and CD14+ monocytic cells and suppressed that of CD14−CD1a+ dendritic cells from CD36−CD15−CD14−CD1a−IL-6R+ myeloid progenitors. Conversely, CD34+CD38− cell-derived early erythroid progenitors were negative for IL-6R expression. Hyper-IL-6 potentiated the generation of CD36+glycophorinAhigh mature erythroid cells from the IL-6R− early erythroid progenitors. Our results indicate that Hyper-IL-6 augments the generation of CD15+ granulocytic, CD14+ monocytic and CD36+glycophorinAhigh cell and suppresses that of CD14−CD1a+ dendritic cells.