Allodepletion targeting CD25/71 is significantly better than CD25 alone. (A) Proliferative responses to host in primary MLR are undetectable after both CD25 beads and CD25/71 immunomagnetic allodepletion (n = 5). Residual proliferation after allodepletion with anti-CD25 beads or CD25/71 beads after stimulation of donor PBMCs with LCLs. Residual proliferation was calculated using the formula in “Comparison of CD25 versus CD25/71 immunomagnetic depletion.” The median residual proliferation for both CD25 beads and CD25/71 beads was 0%. Line = median, box = 25th-75th percentile, error bars = minimum, maximum values. (B) Enhanced depletion of secondary proliferative responses to host after CD25/71 allodepletion compared with CD25 depletion (n = 8). Rested allodepleted CD25 or CD25/71 PBMCs were restimulated with host or third-party LCLs in a 2° proliferation assay. CD25/71 allodepletion led to significantly reduced residual proliferation to host compared with CD25 alone (P < .01) without affecting third-party responses. (C) Residual alloreactivity to host is lower after CD25/71 allodepletion than CD25 in IFN-γ ELISPOT (n = 8). This figure shows the frequency of cells secreting IFN-γ as determined by ELISPOT assays. Rested allodepleted CD25 or CD25/71 PBMCs were restimulated with host or third-party LCLs in a 2° IFN-γ ELISPOT assay. CD25/71 allodepletion led to significantly reduced residual response to host compared with CD25 beads alone (P < .05) without affecting third-party responses.