Figure 1: P. falciparum growth is reduced in iron-deficient RBCs and iron supplementation eliminates growth attenuation.

(a–c) Growth experiments with RBCs from IDA donors (n=7), IDA+Fe donors (n=5) and IR+Fe donors (n=4) were performed. Growth rate in RBCs from an IR donor served as the control. Bars represent growth of P. falciparum (strains 3D7, Dd2 and FCR3-FMG) in indicated RBCs, normalized to growth in RBCs from IR donors (% Pf growth in IR RBC). Error bars represent the s.d. (a) Bars represent growth in RBCs from IDA donors. Significance was determined by two-tailed paired Student’s t-test. *P<3E⁻¹⁰ as compared with P. falciparum growth in RBCs from IR donors. (b) Bars represent growth in RBCs from IDA+Fe donors. Significance was determined by two-tailed paired Student’s t-test. *P<0.0003 as compared with P. falciparum growth in RBCs from IR donors. (c) Bars represent growth of P. falciparum in RBCs from IR+Fe donors at enrollment, 1 month and 2 months on iron, normalized to growth in RBCs from IR donors (% Pf growth in IR RBC). Significance was determined by one-way analysis of variance. ^†P<0.02 for strain 3D7and nonsignificant (n.s.) for strains Dd2 and FCR3-FMG. (d) Mean growth rate of P. falciparum in RBCs from each individual IDA (□), IR+Fe (x) and IDA+Fe (▪) donor plotted against the growth rate of P. falciparum in corresponding control RBCs from non-supplemented IR donors. Data were analysed by mixed effects regression. The Y=X line was fit to the growth rates (in RBCs from IR donors). Points below the Y=X line indicate growth rates less than that within RBCs from IR donors. (e) Graphical summary of the mixed effects regression analysis shown in d. Donor and parasite preparation were fitted as crossed random effects. The bars show the estimated parasite growth of P. falciparum in RBCs from the IDA, IDA+Fe and IR+Fe donors as a percent of P. falciparum growth in RBCs from non-supplemented IR donors. Error bars represent the 95% confidence interval.