DBA therapies do not regulate the expression of RPS19 or ribosomal genes. As illustrated in panel A, CD34⁺ cells were treated with Epo plus combinations of dexamethasone (dex), IL-3, and SCF, and gene expression was analyzed using oligonucleotide microarrays. In panels B and C, RPS19 expression and the mean expression of all ribosomal genes in CD34⁺ cells were assessed by microarrays. Gene expression for each treatment condition and time point is shown relative to gene expression in cells exposed only to Epo. In panel D, RPS19 expression was evaluated by real-time RT-PCR in HEL cells treated with dexamethasone or IL-3. RPS19 expression is depicted relative to untreated cells (mean and SEM).