TFRC and myelodysplastic syndrome: In accordance with the effects of rhS100A9 treatment, incubation of healthy donor BM-MNC with MDS patient plasma triggered significant increases in the percentage of PD-1+CD34+ HSPCs (Fig. 4d; P < 0.05) and PD-1+CD71+ erythroid progenitors (Fig. 4e; P < 0.005).