PMID- 36966873 OWN - NLM STAT- MEDLINE DCOM- 20230605 LR - 20230608 IS - 2666-6367 (Electronic) IS - 2666-6367 (Linking) VI - 29 IP - 6 DP - 2023 Jun TI - Effect of mTOR Inhibition with Sirolimus on Natural Killer Cell Reconstitution in Allogeneic Stem Cell Transplantation. PG - 376.e1-376.e11 LID - S2666-6367(23)01201-0 [pii] LID - 10.1016/j.jtct.2023.03.023 [doi] AB - Sirolimus is an inhibitor of the mammalian target of rapamycin (mTOR) and is emerging as a promising component of graft-versus-host disease (GVHD) prophylaxis regimens in the context of allogeneic hematopoietic stem cell transplantation (HSCT). Multiple studies have explored the clinical benefits of adding sirolimus to GVHD prophylaxis; however, detailed immunologic studies have not yet been carried out in this context. Mechanistically, mTOR is at the center of metabolic regulation in T cells and natural killer (NK) cells and is critical for their differentiation to mature effector cells. Therefore, close evaluation of the inhibition of mTOR in the context of immune reconstitution post-HSCT is warranted. In this work, we studied the effect of sirolimus on immune reconstitution using a biobank of longitudinal samples from patients receiving either tacrolimus/sirolimus (TAC/SIR) or cyclosporin A/methotrexate (CSA/MTX) as conventional GVHD prophylaxis. Healthy donor controls, donor graft material, and samples from 28 patients (14 with TAC/SIR, 14 with CSA/MTX) at 3 to 4 weeks and 34 to 39 weeks post- HSCT were collected. Multicolor flow cytometry was used to perform broad immune cell mapping, with a focus on NK cells. NK cell proliferation was evaluated over a 6-day in vitro homeostatic proliferation protocol. Furthermore, in vitro NK cell responses to cytokine stimulation or tumor cells were evaluated. Systems-level assessment of the immune repertoire revealed a deep and prolonged suppression (weeks 34 to 39 post-HSCT) of the naive CD4 T cell compartment with relative sparing of regulatory T cells and enrichment of CD69(+)Ki-67(+)HLA-DR(+) CD8 T cells, independent of the type of GVHD prophylaxis. Early after transplantation (weeks 3 to 4), while patients were still on TAC/SIR or CSA/MTX, we found a relative increase in less-differentiated CD56(bright) NK cells and NKG2A(+)CD57(-)KIR(-) CD56(dim) NK cells and a distinct loss of CD16 and DNAM-1 expression. Both regimens led to suppressed proliferative responses ex vivo and functional impairment with preferential loss of cytokine responsiveness and IFN-gamma production. Patients who received TAC/SIR as GVHD prophylaxis showed delayed NK cell reconstitution with lower overall NK cell counts and fewer CD56(bright) and NKG2A(+) CD56(dim) NK cells. Treatment with sirolimus-containing regimens generated similar immune cell profiles as conventional prophylaxis; however, the NK cell compartment seemed to be composed of slightly more mature NK cells. These effects were also present after the completion of GVHD prophylaxis, suggesting that mTOR inhibition with sirolimus leaves a lasting imprint on homeostatic proliferation and NK cell reconstitution following HSCT. CI - Copyright (c) 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved. FAU - Haroun-Izquierdo, Alvaro AU - Haroun-Izquierdo A AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden. FAU - Lanuza, Pilar M AU - Lanuza PM AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden. FAU - Pfefferle, Aline AU - Pfefferle A AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden. FAU - Netskar, Herman AU - Netskar H AD - Institute for Cancer Research, Department of Cancer Immunology, University of Oslo, Oslo University Hospital, Norway. FAU - Ask, Eivind H AU - Ask EH AD - Institute for Cancer Research, Department of Cancer Immunology, University of Oslo, Oslo University Hospital, Norway. FAU - Torlen, Johan AU - Torlen J AD - Department of Cellular Therapy and Allogeneic Stem Cell Transplantation, Karolinska University Hospital, Stockholm, Sweden. FAU - Bjorklund, Andreas AU - Bjorklund A AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden; Department of Cellular Therapy and Allogeneic Stem Cell Transplantation, Karolinska University Hospital, Stockholm, Sweden. FAU - Sohlberg, Ebba AU - Sohlberg E AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden. FAU - Malmberg, Karl-Johan AU - Malmberg KJ AD - Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden; Institute for Cancer Research, Department of Cancer Immunology, University of Oslo, Oslo University Hospital, Norway. Electronic address: kalle.malmberg@ki.se. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20230325 PL - United States TA - Transplant Cell Ther JT - Transplantation and cellular therapy JID - 101774629 RN - W36ZG6FT64 (Sirolimus) RN - YL5FZ2Y5U1 (Methotrexate) RN - 0 (Cytokines) RN - EC 2.7.1.1 (MTOR protein, human) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) SB - IM MH - Humans MH - Sirolimus/pharmacology/therapeutic use MH - *Graft vs Host Disease/prevention & control MH - *Hematopoietic Stem Cell Transplantation MH - Killer Cells, Natural MH - Methotrexate MH - Cytokines/metabolism MH - TOR Serine-Threonine Kinases/metabolism OTO - NOTNLM OT - Cyclosporin A OT - Graft-versus-host disease OT - HSCT OT - NK cell OT - Rapamycin OT - Sirolimus EDAT- 2023/03/27 06:00 MHDA- 2023/06/05 06:42 CRDT- 2023/03/26 20:24 PHST- 2023/01/22 00:00 [received] PHST- 2023/03/09 00:00 [revised] PHST- 2023/03/20 00:00 [accepted] PHST- 2023/06/05 06:42 [medline] PHST- 2023/03/27 06:00 [pubmed] PHST- 2023/03/26 20:24 [entrez] AID - S2666-6367(23)01201-0 [pii] AID - 10.1016/j.jtct.2023.03.023 [doi] PST - ppublish SO - Transplant Cell Ther. 2023 Jun;29(6):376.e1-376.e11. doi: 10.1016/j.jtct.2023.03.023. Epub 2023 Mar 25.