“…Many bioactive compounds, including the small molecules in this study, are lipophilic ( Table 1 ), and continued association with host cell plasma membranes or modification upon entry into the RBC to effectuate sequestration may facilitate antiparasitic potency during infection. Interestingly, in melanoma patients trametinib was observed to accumulate onto RBCs ( Isberner et al., 2022 ); given our findings that an effect of the drug on the RBC does not persist beyond transient exposure, association of trametinib with the host cell is likely dynamic. We note that in our measurements across a broad panel of compounds, we observed minimal PS exposure for both FTY720 and Sorafenib ( Supplementary Table 2 ), each of which have otherwise been reported in individual studies to stimulate the signal on erythrocytes ( Eberhard et al., 2010 ; Lupescu et al., 2012 ).…”