Summary of depletion efficacy in 9 consecutive photodepletion (PD) experiments. Displayed P values were obtained using a 2-tailed Wilcoxon matched pair test. (A) Scatterplots (horizontal bars represent the median) of depletion efficacy in 6 mismatched experiments (Exp's I-III, VII-IX) as determined by mixed lymphocyte reactions (MLRs) one day after PD and calculated versus baseline alloreactivity of the untreated primary coculture: Depletion index = [alloreactivity of untreated control]/[alloreactivity of PD product]. (B) Scatterplots (horizontal bars represent the median) of depletion efficacy in 6 mismatched experiments (Exp's I-III, VII-IX) as determined by MLR and calculated versus baseline alloreactivity of unmanipulated responder PBMCs: Depletion index = [alloreactivity of unmanipulated responder]/[alloreactivity of PD product]. (C) Mismatched experiments (Exps I-III, VII-IX) and alloreactivity of MLRs before and after PD (N = 6). (D-F) Matched experiments (Exps IV-VI) and helper T-lymphocyte precursor (HTLp) frequency before and after PD (N = 3). Stim indicates irradiated stimulator cells; Pat, patient PBMCs; Resp, unmanipulated responder PBMCs; 3rdP, pooled third-party PBMCs; UC, untreated control; ExLy, expanded lymphocytes; PD/_5.0TH and PD/_7.5TH, PD products generated using 5.0 and 7.5 μM TH9402, respectively; DI, depletion index; and cpm, counts per minute.