Effect of anticytokine antibodies on autonomous BFU-E growth from PV cells in three patients. PBMNCs were cultured in methylcellulose with medium alone or with antibodies against GM-CSF, IL-3, G-CSF, SCF, or IGF-1, respectively. Colony growth was assessed after 14 days. Results represent mean values ± SD from triplicates. * Significant change from control with P value at least <.05.