Clearance of LPC-treated RBCs by isolated perfused human spleens. (A) Data from a representative experiment showing kinetics of circulating LPC-treated RBCs recovered from the perfusate over 2 hours of splenic perfusion. RBCs were differentially labeled with the lipophilic fluorescent probes PHK26 and/or PKH67, enabling the distinction of 4 separate LPC-treated RBC populations by flow cytometry. (B) Linear regression fit of the correlation between EI_max and the level of LPC-treated RBC retention within the spleen (n = 9 independent experiments).