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-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_H1 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.