Clearance of iRBCs by the isolated-perfused human spleen. (A) Parasitemia of P falciparum FUP schizont-iRBCs (▲) and ring-iRBCs (●) in the perfusate during 120 minutes of perfusion in 1 of 6 independent experiments with isolated-perfused human spleens (all 6 experiments shown in Figure S1, a1-6). (B) Transmission electron microscopy of an end-experiment spleen sample showing a schizont-iRBC (S). (B,C) Bar represents 1 with knobs (C, arrows) in the lumen of a sinus (B, SL) of the red pulp, and a knobless ring-iRBC (B-D, R), in the cords (B, Co). Another example of retained ring-iRBC is shown in Figure 4H,I.