Sanchez-Fueyo et al at King’s College Hospital in London, UK, assessed the safety of infusing two doses of ex-vivo-expanded T-regulatory cells (Tregs) to liver transplant recipients. Treg infusions can provide anti-rejection effect with fewer side effects than small molecule immunosuppressants, and reduce the need for these immunosuppressants. No adverse events were reported in this study. Immunophenotyping revealed an increase in circulating Tregs for up to a month after infusion following the higher dose infusion of 3-4.5 million Tregs/kg. In these patients, donor-specific T-cytotoxic memory cells declined steadily across three serial measurements conducted pre-infusion and at 1 week and 1 month after infusion. No changes were seen in reactivity to non-identical cells. The lower dose Treg infusion had no effect on donor-reactive T-cytotoxic memory cells. Thus, immune cell function assessment may help to evaluate the effect of cell therapy in transplant patients.

Reference: Sánchez-Fueyo A, Whitehouse G, Grageda N, Cramp ME, Lim TY, Romano M, Thirkell S, Lowe K, Fry L, Heward J, Kerr A, Ali J, Fisher C, Lewis G, Hope A, Kodela E, Lyne M, Farzaneh F, Kordasti S, Rebollo-Mesa I, Jose Lozano J, Safinia N, Heaton N, Lechler R, Martínez-Llordella M, Lombardi G. Applicability, safety, and biological activity of regulatory T cell therapy in liver transplantation. Am J Transplant. 2020 Apr;20(4):1125-1136. doi: 10.1111/ajt.15700. Epub 2020 Feb 3.PMID: 31715056