Angus W. Thomson

Immune cell–based therapies are promising strategies to facilitate immunosuppression withdrawal after organ transplantation. Regulatory dendritic cells (DCreg) are innate immune cells that down-regulate alloimmune responses in preclinical models. Here, we performed clinical monitoring and comprehensive assessment of peripheral and allograft tissue immune cell populations in DCreg-infused live-donor liver transplant (LDLT) recipients up to 12 months (M) after transplant. Thirteen patients were given a single infusion of donor-derived DCreg 1 week before transplant (STUDY) and were compared with 40 propensity-matched standard-of-care (SOC) patients. Donor-derived DCreg infusion was well tolerated in all STUDY patients. There were no differences in postoperative complications or biopsy-confirmed acute rejection compared with SOC patients up to 12M. DCreg administration was associated with lower frequencies of effector T-bet + Eomes + CD8 + T cells and CD16 bright natural killer (NK) cells and an increase in putative tolerogenic CD141 + CD163 + DCs compared with SOC at 12M. Antidonor proliferative capacity of interferon-γ + (IFN-γ + ) CD4 + and CD8 + T cells was lower compared with antithird party responses in STUDY participants, but not in SOC patients, at 12M. In addition, lower circulating concentrations of interleukin-12p40 (IL-12p40), IFN-γ, and CXCL10 were detected in STUDY participants compared with SOC patients at 12M. Analysis of 12M allograft biopsies revealed lower frequencies of graft-infiltrating CD8 + T cells, as well as attenuation of cytolytic T H 1 effector genes and pathways among intragraft CD8 + T cells and NK cells, in DCreg-infused patients. These reductions may be conducive to reduced dependence on immunosuppressive drug therapy or immunosuppression withdrawal.