LCP4 treatment inhibits the proliferation and multilineage differentiation potential of MF splenic and PB CD34⁺ cells. MF splenic or PB CD34⁺ cells were treated with cytokines alone or cytokines plus LCP4 (100 nM, 500 nM) for 1 to 2 weeks. One week after the culture, the media were replaced with fresh media supplemented with or without LCP4 and cells were cultured for another week. Cells generated were phenotypically characterized and were assayed for HPCs. The percentage of the absolute number of CD34⁺Lin⁻ cells (A), all classes of assayable HPCs ([B] 1 week and [C] 2 weeks after the culture), as well as mature MKs (CD41a⁺CD34⁻CD15⁻) (D) and myeloid cells (CD15⁺CD34⁻CD41a⁻) (E), generated in the cultures of MF splenic or PB CD34⁺ cells exposed to cytokines plus LCP4 relative to that generated in the culture exposed to cytokines alone is shown. *P < .05; **P < .01; ***P < .001. n = 14 (8 splenic MF and 6 PB MF). WK, week.