PlGF and EKLF are expressed simultaneously at high levels in vivo in patients with SCD and expression of PlGF follows EKLF expression in isolated erythroid cells. (A) PlGF and (B) EKLF expression is significantly higher among SCD patients than healthy controls, and (C) expression of PlGF and EKLF is correlated with each other, indicating that PlGF may be the target of EKLF. (D) Erythroid progenitor cells were cultured by a 2-phase approach and treated with EPO, cells were harvested, and quantitative PCR performed to detect the expression of EKLF and PlGF. The results show that EKLF and PlGF are expressed during erythroid development, with EKLF expression preceding that of PlGF. (E-F) EKLF and PlGF expression in isolated human erythroid progenitor cells. Erythroid progenitor cells were cultured, and then EKLF was transfected by electroporation. Cells were harvested on day 5. Overexpression of EKLF leads to increased PlGF expression in erythroid progenitor cells.