A fraction of CD4+FOXP3+ regulatory T cells persists after photodepletion. (A) Scatterplots of quantitative reverse transcription-PCR for FOXP3 mRNA in magnetically selected CD4+ cells performed between day + 2 and day + 4 after photodepletion (N = 5). Horizontal bars represent the median of each group. A 2-tailed Wilcoxon matched pair test was applied. (B) Flow cytometry showing surface staining for CD25 and intracellular staining for FOXP3 protein in gated CD4+ cells performed on day +4 after photodepletion (Exp II). One representative experiment of 5 is displayed. Resp indicates unmanipulated responder PBMCs; UC, untreated control (primary coculture); and PD/5.0TH and PD/7.5TH, photodepleted product using 5.0 μM and 7.5 μM TH9402, respectively.