Figure 4.

Blasts from high-risk MDS express CD123 and are sensitive to SL401. (A-B) SL-401 depletes CD123⁺ MDS blasts. MDS samples cultured with vehicle or SL-401 (1 μg/ml, 2 μg/ml) for 120 hours were stained for various myeloid markers (CD45, CD33, CD34, CD123, and viability stain) and live cells were counted. (A) Representative MDS-RAEB cells cultured with varying doses of SL-401 for 120 hours. Density plots gated on live CD45⁺ population are shown. (B) Live CD34⁺ blast concentration (bars), live CD34⁺ blast % (red lines) and live lymphoid % (green lines) are shown for each sample (N=6 CD123⁺ MDS) P=0.0183 for live CD34⁺ blast concentration between SL401 1 μg/ml vs. vehicle, and P=0.0063 for live CD34⁺ blast concentration between SL401 2 μg/ml vs. vehicle. CD123⁻ MDS sample (MDS 1) was included as a control.