PIGAKO and DKO can be used to monitor therapeutic complement inhibition. (A) Example tracing of solid organ transplant-associated (SOT) TMA sample on therapeutic eculizumab ran on PIGAKO cells with or without addition of sutimlimab or eculizumab. (B) Example tracing of CM01 remission sample after being started on eculizumab on DKO cells. (C) Summary of relative luminescence at 1 hour for CM-TMA samples (n = 14) on treatment with C5 inhibition (acute and remission samples off treatment included for comparison). (D) Example tracing of CM21 on ravulizumab therapy with or without the addition of eculizumab, sutimlimab, or FDi on PIGAKO cells. (E) Example tracing of HC on DKO with increasing concentrations of eculizumab. (F) Example tracing of HC on PIGAKO with increasing concentrations of sutimlimab. (G) Example tracing of HC on DKO with increasing concentrations of C1 inhibitor. (H) Serum from acute CM-TMA sample (CM06) on eculizumab therapy was diluted with pooled normal human serum on PIGAKO. For panels A-B,D-H, example tracings plotted as mean ± SD for each triplicate. For panel C, P values were calculated using 1-way ANOVA for Dunnett multiple-comparisons test. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. ns, not significant; RLU, relative luminescence units.