Finding of the regulation of various gene expression by cytokine indluding IFN-γ in hematopoietic stem cell will light up the understanding of pathogenesis of aplastic anemia in various aspects. To study on aplastic anemia, however, we have to circumvent the difficulty of directly obtaining bone marrow stem cells from the patient. Therfore, we tried to find out a cell can replace the bone marrow stem cells for study on cell signaling pathway and regulation of gene expression by IFN-γ.

HL-60 cells, of 20 ng/mL of IFN-γ. Total RNA was isolated from the cells and RT-PCR of the indoleamine 2,3-dioxygenase (IDO), IFN-γ, TNF-α, MIP-1α, and TGF-β2 was carried out for the estimation of the gene expression.

IFN-γ induced IDO gene expression of mononuclear cells from umbilical cord blood showed similar pattern as compared to that of bone marrow. Whether INF-γ was treated or nor, TNF-α was expressed in both mononuclear cells from umbilical cord blood and bone marrow. However, HL-60 cells showed different expression patterns. HL-60 cells would express neither IDO nor TNF-α even under the culture with 20 ng/mL of IFN-γ.

Our results showed bone marrow can be replaced with mononuclear cells from umbilical cord blood in the study on the relation between aplastic anemia and IFN-γ including IFN-γ cell signaling pathway.