P falciparum growth in red cells from individuals with EPP and XLDPP. Comparison of P falciparum growth in EPP and normal RBCs (A) and in XLDPP and normal RBCs (B). Values are expressed as fold changes in parasitemia (relative to inocula levels) (±SD) measured after culturing for 24, 48, and 72 hours. Growth in cells from 4 individuals with EPP was tested separately against 4 different normal blood samples. Significant reductions in parasite growth are indicated (*P < .05, **P < .01). Growth in cells from 3 individuals with XLDPP was tested against a single normal blood sample. Significant increases in parasite growth are indicated (*P < .05, **P < .01). SD, standard deviation.