P falciparum invasion efficiency in density-separated RBCs with various congenital abnormalities. RBCs from 6 different donors with the indicated pathologies were harvested from the arabinogalactan concentration ranges shown on the abscissa and used to sustain P falciparum cultures in conditions similar to those indicated in Figure 6. “All” indicates parasite counts in the original, unfractionated RBC samples. Parasite counts were assessed after 38 hours of incubation on Giemsa-stained blood smears. At least 1000 RBCs were counted per slide on 3 different slides. The columns and error bars report the means and SDs of these triplicate counts.