Donor Lymphocyte Infusion–Mediated Graft-versus-Host Responses in a Preclinical Swine Model of Haploidentical Hematopoietic Cell Transplantation  Raimon Duran-Struuck, Abraham J. Matar, Rebecca L. Crepeau, Alexander G.S. Teague, Benjamin M. Horner, Vimukthi Pathiraja, Thomas R. Spitzer, Jay A. Fishman, Roderick T. Bronson, David H. Sachs, Christene A. Huang  Biology of Blood and Marrow Transplantation  Volume 22, Issue 11, Pages 1953-1960 (November 2016) DOI: 10.1016/j.bbmt.2016.08.011 Copyright © 2016 The American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 1 Long-lasting donor unresponsiveness post-HCT. Three representative long-term tolerant animals that received a DLI after a RIC-HCT. Animal 13272 received 2 DLIs (arrows) on days 745 and 984 post-HCT, respectively. The first DLI was unmodified, whereas the second DLI was a “sensitized” DLI. Animal 14225 received a DLI on day 110 post-HCT. Animal 13476 received a DLI on day 482 post-HCT. Chimerism is shown in the top panels. Percent donor-derived chimerism is shown on the y axis and days post-transplantation on the x axis. CMLs were done at different time points. White squares represent anti-self responses, triangles anti–third party responses, and dark squares anti-donor responses. The y axis represents percent specific lysis (PSL) and the x axis represents the effector-to-target ratio (E:T). No effects after DLI were observed in these 3 representative animals (*P < .05). Biology of Blood and Marrow Transplantation 2016 22, 1953-1960DOI: (10.1016/j.bbmt.2016.08.011) Copyright © 2016 The American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 2 DLI after leukapheresis. Animal 14980 received a DLI on day 218 post-HCT. The animal converted to donor chimerism without GVHD. Animal 19141 received a 37 million CD3+ T cell DLI on day 453 post-HCT, and subsequently developed GVHD. Animal 19560 underwent leukaphoresis on day 59 post-HCT and subsequently received a 50 million CD3 T cell DLI. Acute GVHD developed. Animals 17467 and 17469 each received a 50 million CD3 T cell DLI on days 96 and 62 after haplo-HCT, respectively. Animal 17467 had evidence of increased chimerism before succumbing to a non–GVHD-related condition. No effect was observed in animal 17469, and the DLI dose was escalated to 150 million (megadose) CD3+ T cell DLI on day 463 post-HCT. The animal converted to full donor chimerism and developed skin-only GVHD. Biology of Blood and Marrow Transplantation 2016 22, 1953-1960DOI: (10.1016/j.bbmt.2016.08.011) Copyright © 2016 The American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 3 Sensitized and CC DLIs. (A, left) Percent chimerism of animal 14376 after haploidentical HCT. A 50 million CD3+ T cell/kg DLI was delivered on day 36 and a “sensitized” DLI 1 year post-HCT (arrows). (A, middle) CML from a naive AC (used in comparison with the right panel). (A, right) CML from animal 14179 after being sensitized by host MHC-matched skin (to animal 14376, an AD). Assay was performed 92 days after skin grafting. (B, left) Percent chimerism of animal 16626 after haploidentical HCT. The animal was a low level chimera in all lineages. Animal 16626 received a donor AC DLI of 1 million CD3 T cells on day 152 post-HCT followed by a second DLI of 50 million AC donor-matched CD3+ T cells/kg (arrows). No effect of either DLI was observed. The third and last DLI was a CC DLI. This DLI was haplo-matched to donor cells (AC) but completely mismatched to the host MHC (AD). (B, middle) CML from chimeric animal 16626 responding to a third-party control while unresponsive to the PBMCs from the CC DLI donor. (B, right) CML using CC effectors and animal 16626 chimeric cells as targets before the DLI. Biology of Blood and Marrow Transplantation 2016 22, 1953-1960DOI: (10.1016/j.bbmt.2016.08.011) Copyright © 2016 The American Society for Blood and Marrow Transplantation Terms and Conditions