ABT007 stimulates in vitro erythropoiesis. (A) ABT007 stimulates the proliferation of EPO-responsive F36E human erythroleukemic cells.⁸  Error bars represent standard deviation (SD) calculated from the average of duplicate counts. (B) ABT007 supports the formation of erythroid colonies from hematopoietic precursor cells. Error bars represent standard deviation (SD) calculated from the average of duplicate counts. Typical colonies, identified microscopically, are shown below for (C) the isotype control–, (D) EPO-, and (E) ABT007-treated cells. The colonies were red in color.