Regulatory T cells from patients with end-stage organ disease can be isolated, expanded and cryopreserved according good manufacturing practice improving their function

Background Here, we isolated, expanded and functionally characterized regulatory T cells (Tregs) from patients with end stage kidney and liver disease, waiting for kidney/liver transplantation (KT/LT), with the aim to establish a suitable method to obtain large numbers of immunomodulatory cells for adoptive immunotherapy post-transplantation. Methods We first established a preclinical protocol for expansion/isolation of Tregs from peripheral blood of LT/KT patients. We then scaled up and optimized such protocol according to good manufacturing practice (GMP) to obtain high numbers of purified Tregs which were phenotypically and functionally characterized in vitro and in vivo in a xenogeneic acute graft-versus-host disease (aGVHD) mouse model. Specifically, immunodepressed mice (NOD-SCID-gamma KO mice) received human effector T cells with or without GMP-produced Tregs to prevent the onset of xenogeneic GVHD. Results Our small scale Treg isolation/expansion protocol generated functional Tregs. Interestingly, cryopreservation/thawing did not impair phenotype/function and DNA methylation pattern of FOXP3 gene of the expanded Tregs. Fully functional Tregs were also isolated/expanded from KT and LT patients according to GMP. In the mouse model, GMP Tregs from LT or KT patient proved to be safe and show a trend toward reduced lethality of acute GVHD. Conclusions These data demonstrate that expanded/thawed GMP-Tregs from patients with end-stage organ disease are fully functional in vitro. Moreover, their infusion is safe and results in a trend toward reduced lethality of acute GVHD in vivo, further supporting Tregs-based adoptive immunotherapy in solid organ transplantation

Reinfusion of highly purified CD133+ bone marrow-derived stem/progenitor cells in patients with end-stage liver disease: A phase I clinical trial

Background: Bone marrow stem/progenitor cells seem to be effective in liver regeneration after tissueinjury. Aim: To evaluate the feasibility and safety of the mobilization and reinfusion of CD133+stem/progenitorcells in patients with end-stage liver disease.Methods: Autologous CD133+stem/progenitor cells, mobilized with granulocyte-colony stimulating fac-tor, were collected by leukapheresis and reinfused at increasing doses through the hepatic artery startingfrom 5 × 104/kg up to 1 × 106/kg.Results: 16 subjects with Model for End-stage Liver Disease (MELD) score between 17 and 25 wereenrolled, 14 mobilized an adequate number of CD133+stem/progenitor cells and 12 were reinfused.No severe adverse events related to the procedure were reported. MELD score significantly worsenedduring mobilization in Child Turcotte Pugh-C patients. A significant improvement of liver function wasobserved 2 months after reinfusion (MELD 19.5 vs 16; P = 0.045). Overall, 5 patients underwent livertransplantation within 12 months from reinfusion and 2 died because of progressive liver failure.Conclusions: CD133+stem/progenitor cells reinfusion in patients with end-stage liver disease is feasi-ble and safe. A worsening of liver function was observed during mobilization in Child Turcotte Pugh-Cpatients. The temporary improvement of MELD score after reinfusion suggests that stem cells therapymay be a “bridge to transplant” approach for these patients