Donor-derived regulatory dendritic cell infusion modulates effector CD8⁺ T cell and NK cell responses after liver transplantation

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-gamma(+) (IFN-gamma(+)) 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-gamma, 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 TH1 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.