CD34+CD38- hematopoietic precursors derived from human embryonic stem cells exhibit an embryonic gene expression pattern

Gene expression patterns of CD34(+)CD38(-)cells derived from human embryonic stem cells (ESCs) were compared with those of cells isolated from adult human bone marrow (BM) using microarrays; 1692 and 1494 genes were expressed at levels at least 3-fold above background in cells from BM and ESCs, respectively. Of these, 494 showed similar levels of expression in cells from both sources, 791 genes were overexpressed in cells from BM (BM versus ESCs, at least 2-fold), and 803 genes were preferentially expressed in cells from ESCs (ESCs versus BM, at least 2-fold). The message of the fit-3 gene was markedly decreased in cells from ESCs, whereas there was substantial fit-3 expression in cells from BM. High levels of embryonic E-globin expression were observed-but no adult P-globin message-in CD34(+)CD38(-) cells from ESCs, whereas high levels of P-globin expression-but no embryonic E-globin message-could be detected in cells from BM. Furthermore, high levels of major histocompatibility complex (MHC) gene expression were demonstrated in cells from BM but very low levels of MHC message in corresponding cells from ESCs. These observations demonstrate that CD34(+)CD38(-) cells derived from ESCs correspond consistently to an early developmental stage at which the yolk sac and fetal liver are the primary sites of hematopoiesis. (C) 2004 by The American Society of Hematology