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Xu H, Lee HJ, Schmitz R, Shaw BI, Li S, Kirk AD. Age-related effects on thymic output and homeostatic T cell expansion following depletional induction in renal transplant recipients. Am J Transplant 2021; 21:3163-3174. [PMID: 33942491 PMCID: PMC8429231 DOI: 10.1111/ajt.16625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 04/07/2021] [Accepted: 04/15/2021] [Indexed: 01/25/2023]
Abstract
Thymic output and homeostatic mature cell proliferation both influence T cell repopulation following depletional induction, though the relative contribution of each and their association with recipient age have not been well studied. We investigated the repopulating T cell kinetics in kidney transplant recipients who underwent alemtuzumab induction followed by belatacept/rapamycin-based immunosuppression over 36-month posttransplantation. We focused specifically on the correlation between repopulating T cell subsets and the age of patients. Substantial homeostatic Ki67-expressing T cell proliferation was seen posttransplantation. A repertoire enriched for naïve T (TNaïve ) cells emerged posttransplantation. Analysis by generalized estimating equation linear models revealed a strong negative linear association between reconstituting TNaïve cells and advancing age. A relationship between age and persistence of effector memory cells was shown. We assessed thymic output and found an increase in the frequency of recent thymic emigrants (RTEs, CD4+ CD31+ ) at 12-month posttransplantation. Patients under 30 years of age showed significantly higher levels of CD4+ CD31+ cells than patients over 55 years of age pre- and posttransplantation. IL-7 and autologous mature dendritic cells (mDCs) induced CD57- cell proliferation. In contrast, mDCs, but not IL-7, induced CD57+ cell proliferation. This study establishes the relationship between age and thymic output during T cell homeostatic repopulation after alemtuzumab induction. Trial Registration: ClinicalTrials.gov - NCT00565773.
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Affiliation(s)
- He Xu
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC, USA,To whom correspondence should be addressed: He Xu, MD, Allan D. Kirk, MD, PhD, Department of Surgery, Duke University School of Medicine, Edwin Jones Building Room 368, Durham, NC 27710, Phone: (919)684-4371, ,
| | - Hui-Jie Lee
- Department of Biostatistics & Bioinformatics, Duke University School of Medicine, Durham, NC, USA
| | - Robin Schmitz
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Brian I Shaw
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Shu Li
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Allan D Kirk
- Duke Transplant Center, Department of Surgery, Duke University School of Medicine, Durham, NC, USA,To whom correspondence should be addressed: He Xu, MD, Allan D. Kirk, MD, PhD, Department of Surgery, Duke University School of Medicine, Edwin Jones Building Room 368, Durham, NC 27710, Phone: (919)684-4371, ,
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2
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Gong S, Hao X, Bi Y, Yang C, Wang W, Mickael HK, Zhang Y, Chen S, Qian Z, Huang F, Wei D, Yu W. Hepatitis E viral infection regulates estrogen signaling pathways: Inhibition of the cAMPK-PKA-CREB and PI3K-AKT-mTOR signaling pathways. J Med Virol 2021; 93:3769-3778. [PMID: 33128390 DOI: 10.1002/jmv.26641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 10/17/2020] [Accepted: 10/25/2020] [Indexed: 12/22/2022]
Abstract
Hepatitis E virus (HEV) infection has become a global concern with high mortality rates among pregnant women, especially those in their third trimester of pregnancy. Estrogen plays an important role in mediating the body, regulating physiological and pathological processes. Estrogen is activated by binding to estrogen receptors (ERs) and mediates rapid signaling events by pathways that involve transmembrane ERs. Our previous study had confirmed that high estrogen levels during pregnancy are associated with high HEV titers. However, the association between HEV infection and estrogen signaling pathways remains unclear. In the present study, the regulation of estrogen signaling pathways by HEV infection was evaluated. Results demonstrated that HEV infection significantly inhibits the cAMP-PKA-CREB and PI3K-AKT-mTOR signaling pathways, but is independent of the Ras-Raf-MEK-ERK signaling pathway. In summary, the increasing estrogen levels and highly activated ERα during pregnancy aggravates HEV replication. The exacerbation of HEV replication, in turn, inhibits ERα expression and suppresses both cAMP-PKA-CREB and PI3K-AKT-mTOR signaling pathways.
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Affiliation(s)
- Shilin Gong
- Medical School, Kunming University of Science and Technology, Kunming, PR China
- Yunnan Provincial Key Laboratory of Clinical Virology, Kunming, PR China
| | - Xianhui Hao
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Yanhong Bi
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Chenchen Yang
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Wenjing Wang
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Houfack K Mickael
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Yike Zhang
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Shuangfeng Chen
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Zhongyao Qian
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Fen Huang
- Medical School, Kunming University of Science and Technology, Kunming, PR China
- Yunnan Provincial Key Laboratory of Clinical Virology, Kunming, PR China
| | - Daqiao Wei
- Medical School, Kunming University of Science and Technology, Kunming, PR China
| | - Wenhai Yu
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, PR China
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3
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Shaw BI, Schmitz R, Flores WJ, Magnani DM, Li J, Song M, Kirk AD. A comparative study of human-and rhesus-specific antithymocyte globulins in Rhesus macaques. Clin Transplant 2021; 35:e14369. [PMID: 34021521 DOI: 10.1111/ctr.14369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/10/2021] [Accepted: 05/17/2021] [Indexed: 11/28/2022]
Abstract
Rabbit antithymocyte globulin (RATG) preparations are widely used in transplantation. They are developed in vivo against thymocytes and contain polyclonal antibodies specific for myriad cellular targets. The rhesus monkey is commonly used as a preclinical transplant model, but the fidelity of commercially available human-specific RATGs to anticipate the effects of RATGs in rhesus has not been established. We therefore developed two rhesus-specific ATGs (rhATG) and compared them to human-specific RATG (huATG, Thymoglobulin® ) in rhesus monkeys, assessing the magnitude and phenotype of depletion peripherally and in lymph nodes. Four primates were assigned to each group and received 20 mg/kg of drug. Depletion, repopulation, and changes in lymphocyte subsets were evaluated in peripheral blood and lymph nodes by flow cytometry over four months. We observed similar qualitative changes in lymphocyte subsets, but a generally more profound depletion with huATG compared to either rhATG. Peripheral homeostatic proliferation rather than thymic output was the major mechanism for repopulation with all RATGs. Repopulation was slower but qualitatively similar when examining RATGs in additional animals receiving concomitant chronic immunosuppression. Depletional induction is similar to human- and rhesus-specific RATGs in rhesus macaques. Both rhesus- and human-specific agents appear appropriate for preclinical modeling of clinical RATG use.
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Affiliation(s)
- Brian I Shaw
- Department of Surgery, Duke University, Durham, NC, USA
| | - Robin Schmitz
- Department of Surgery, Duke University, Durham, NC, USA
| | - Walter J Flores
- MassBiologics, University of Massachusetts Medical School, Boston, MA, USA
| | - Diogo M Magnani
- MassBiologics, University of Massachusetts Medical School, Boston, MA, USA
| | - Jie Li
- Department of Surgery, Duke University, Durham, NC, USA
| | - Mingqing Song
- Department of Surgery, Duke University, Durham, NC, USA
| | - Allan D Kirk
- Department of Surgery, Duke University, Durham, NC, USA
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4
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Charnaya O, Seifert M. Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia. Pediatr Transplant 2021; 25:e13811. [PMID: 32871051 DOI: 10.1111/petr.13811] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/18/2020] [Accepted: 07/13/2020] [Indexed: 12/17/2022]
Abstract
Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.
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Affiliation(s)
- Olga Charnaya
- Department of Pediatrics, Johns Hopkins University, Baltimore, MD, USA
| | - Michael Seifert
- Department of Pediatrics, University of Alabama School of Medicine, Birmingham, AL, USA
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5
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Schmitz R, Fitch ZW, Xu H, Ghali A, Mehta AK, Guasch A, Kirk AD. Kidney transplantation using alemtuzumab, belatacept, and sirolimus: Five-year follow-up. Am J Transplant 2020; 20:3609-3619. [PMID: 32515087 DOI: 10.1111/ajt.16121] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/21/2020] [Accepted: 05/28/2020] [Indexed: 01/25/2023]
Abstract
Kidney transplant outcomes are limited by toxicities associated with calcineurin inhibitors and steroids. This trial was conducted to determine whether a costimulation blockade (CoB)-based regimen could achieve acceptable long-term outcomes and graft survival could be maintained solely with CoB. Forty patients underwent alemtuzumab induction followed by belatacept and sirolimus maintenance therapy. Patients were offered weaning to belatacept monotherapy after 1 year and followed for 5 years. Five-year patient and graft survival rates were 100% and 95%, respectively. Graft function remained stable with a mean estimated glomerular filtration rates of 67 ± 21 and 71 ± 19 at 36 and 60 months, respectively. There was no clinical rejection in the first year; subclinical rejection was detected by protocol biopsy in 4 patients. Twelve patients were successfully weaned to belatacept monotherapy. Cytomegalovirus and Epstein-Barr virus reactivations were well controlled, but 9 patients experienced transient BK viremia during the first year. Alemtuzumab produced profound lymphopenia followed by gradual T cell and more rapid B cell reconstitution to a repertoire deviated toward naïve cells with increased regulatory T cells. This regimen effectively prevents allograft rejection without using steroids or calcineurin inhibitors, enriches for naïve cells susceptible to control with CoB, and permits control of rejection with belatacept monotherapy in selected patients.
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Affiliation(s)
- Robin Schmitz
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Zachary W Fitch
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - He Xu
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Ada Ghali
- Emory Transplant Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Aneesh K Mehta
- Emory Transplant Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Antonio Guasch
- Emory Transplant Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Allan D Kirk
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA
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6
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Calabrese LH, Caporali R, Blank CU, Kirk AD. Modulating the wayward T cell: New horizons with immune checkpoint inhibitor treatments in autoimmunity, transplant, and cancer. J Autoimmun 2020; 115:102546. [PMID: 32980229 DOI: 10.1016/j.jaut.2020.102546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 09/02/2020] [Accepted: 09/14/2020] [Indexed: 12/20/2022]
Abstract
The T-cell response is regulated by the balance between costimulatory and coinhibitory signals. Immune checkpoints are essential for efficient T-cell activation, but also for maintaining self-tolerance and protecting tissues from damage caused by the immune system, and for providing protective immunity. Modulating immune checkpoints can serve diametric goals, such that blocking a coinhibitory molecule can unleash anti-cancer immunity whereas stimulating the same molecule can reduce an over-reaction in autoimmune disease. The purpose of this review is to examine the regulation of T-cell costimulation and coinhibition, which is central to the processes underpinning autoimmunity, transplant rejection and immune evasion in cancer. We will focus on the immunomodulation agents that regulate these unwanted over- and under-reactions. The use of such agents has led to control of symptoms and slowing of progression in patients with rheumatoid arthritis, reduced rejection rates in transplant patients, and prolonged survival in patients with cancer. The management of immune checkpoint inhibitor treatment in certain challenging patient populations, including patients with pre-existing autoimmune conditions or transplant patients who develop cancer, as well as the management of immune-related adverse events in patients receiving antitumor therapy, is examined. Finally, the future of immune checkpoint inhibitors, including examples of emerging targets that are currently in development, as well as recent insights gained using new molecular techniques, is discussed. T-cell costimulation and coinhibition play vital roles in these diverse therapeutic areas. Targeting immune checkpoints continues to be a powerful avenue for the development of agents suitable for treating autoimmune diseases and cancers and for improving transplant outcomes. Enhanced collaboration between therapy area specialists to share learnings across disciplines will improve our understanding of the opposing effects of treatments for autoimmune disease/transplant rejection versus cancer on immune checkpoints, which has the potential to lead to improved patient outcomes.
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Affiliation(s)
| | - Roberto Caporali
- University of Milan, Department of Clinical Sciences and Community Health and Rheumatology Division, ASST Pini-CTO Hospital, Milan, Italy
| | | | - Allan D Kirk
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
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7
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Xu H, Mehta AK, Gao Q, Lee HJ, Ghali A, Guasch A, Kirk AD. B cell reconstitution following alemtuzumab induction under a belatacept-based maintenance regimen. Am J Transplant 2020; 20:653-662. [PMID: 31596034 PMCID: PMC7202689 DOI: 10.1111/ajt.15639] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 09/06/2019] [Accepted: 09/24/2019] [Indexed: 01/25/2023]
Abstract
Lymphocyte depletion has been shown to control costimulation blockade-resistant rejection but, in some settings, to exacerbate antibody-mediated rejection (AMR). We have used alemtuzumab, which depletes T and B cells, combined with belatacept and rapamycin and previously reported control of both costimulation blockade-resistant rejection and AMR. To evaluate this regimen's effect on B cell signatures, we investigated 40 patients undergoing this therapy. B cell counts and phenotypes were interrogated using flow cytometry, and serum was analyzed for total IgG, IgM, and donor-specific alloantibody (DSA). Alemtuzumab induction produced pan-lymphocyte depletion; B cells repopulated faster and more completely than T cells. Reconstituting B cells were predominantly naïve, and memory B cells were significantly reduced (P = .001) post repopulation. Two B cell populations with potential immunomodulatory effects-regulatory (CD38hi CD24hi IgMhi CD20hi ) and transitional B cells (CD19+ CD27- IgD+ CD38hi )-were enriched posttransplant (P = .001). Total serum IgG decreased from baseline (P = .016) while IgM levels remained stable. Five patients developed DSAs within 36 months posttransplant, but none developed AMR. Baseline IgG levels in these patients were significantly higher than those in patients without DSAs. These findings suggest that belatacept and rapamycin together limit homeostatic B cell activation following B cell depletion and may lessen the risk of AMR. This regimen warrants prospective, comparative study. ClinicalTrials.gov NCT00565773.
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Affiliation(s)
- He Xu
- Department of Surgery, Duke University School of Medicine, Durham, NC,,Corresponding author: He Xu, M.D., Mailing Address: Department of Surgery, Duke University Medical Center, Edwin Jones Building, Room 368, Durham, NC 27710, Telephone: (919) 681-4853, Fax Number: (919) 681-2779,
| | - Aneesh K. Mehta
- Emory Transplant Center, Emory University, Atlanta, GA, United States
| | - Qimeng Gao
- Department of Surgery, Duke University School of Medicine, Durham, NC
| | - Hui-Jie Lee
- Department of Biostatistics & Bioinformatics, Duke University School of Medicine, Durham, NC
| | - Ada Ghali
- Emory Transplant Center, Emory University, Atlanta, GA, United States
| | - Antonio Guasch
- Emory Transplant Center, Emory University, Atlanta, GA, United States
| | - Allan D. Kirk
- Department of Surgery, Duke University School of Medicine, Durham, NC
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8
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Ochando J, Fayad ZA, Madsen JC, Netea MG, Mulder WJM. Trained immunity in organ transplantation. Am J Transplant 2020; 20:10-18. [PMID: 31561273 PMCID: PMC6940521 DOI: 10.1111/ajt.15620] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/11/2019] [Accepted: 09/15/2019] [Indexed: 01/25/2023]
Abstract
Consistent induction of donor-specific unresponsiveness in the absence of continuous immunosuppressive therapy and toxic effects remains a difficult task in clinical organ transplantation. Transplant immunologists have developed numerous experimental treatments that target antigen-presentation (signal 1), costimulation (signal 2), and cytokine production (signal 3) to establish transplantation tolerance. While promising results have been obtained using therapeutic approaches that predominantly target the adaptive immune response, the long-term graft survival rates remain suboptimal. This suggests the existence of unrecognized allograft rejection mechanisms that contribute to organ failure. We postulate that trained immunity stimulatory pathways are critical to the immune response that mediates graft loss. Trained immunity is a recently discovered functional program of the innate immune system, which is characterized by nonpermanent epigenetic and metabolic reprogramming of macrophages. Since trained macrophages upregulate costimulatory molecules (signal 2) and produce pro-inflammatory cytokines (signal 3), they contribute to potent graft reactive immune responses and organ transplant rejection. In this review, we summarize the detrimental effects of trained immunity in the context of organ transplantation and describe pathways that induce macrophage training associated with graft rejection.
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Affiliation(s)
- Jordi Ochando
- Department of Oncological SciencesIcahn School of Medicine at Mount SinaiNew YorkNew York,Transplant Immunology UnitNational Center of MicrobiologyInstituto de Salud Carlos IIIMadridSpain
| | - Zahi A. Fayad
- Department of RadiologyTranslational and Molecular Imaging InstituteIcahn School of Medicine at Mount SinaiNew YorkNew York
| | - Joren C. Madsen
- Center for Transplantation Sciences and Division of Cardiac SurgeryDepartment of SurgeryMassachusetts General HospitalBostonMassachusetts
| | - Mihai G. Netea
- Department of Internal Medicine and Radboud Center for Infectious DiseasesRadboud University Medical CenterNijmegenThe Netherlands,Department for Genomics & ImmunoregulationLife and Medical Sciences Institute (LIMES)University of BonnBonnGermany
| | - Willem J. M. Mulder
- Department of Oncological SciencesIcahn School of Medicine at Mount SinaiNew YorkNew York,Department of RadiologyTranslational and Molecular Imaging InstituteIcahn School of Medicine at Mount SinaiNew YorkNew York,Laboratory of Chemical BiologyDepartment of Biomedical EngineeringInstitute for Complex Molecular SystemsEindhoven University of TechnologyEindhovenThe Netherlands
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9
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Mulvihill MS, Samy KP, Gao QA, Schmitz R, Davis RP, Ezekian B, Leopardi F, Song M, How T, Williams K, Barbas A, Collins B, Kirk AD. Secondary lymphoid tissue and costimulation-blockade resistant rejection: A nonhuman primate renal transplant study. Am J Transplant 2019; 19:2350-2357. [PMID: 30891931 PMCID: PMC6658331 DOI: 10.1111/ajt.15365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 01/25/2023]
Abstract
Naïve T cell activation requires antigen presentation combined with costimulation through CD28, both of which optimally occur in secondary lymphoid tissues such as lymph nodes and the spleen. Belatacept impairs CD28 costimulation by binding its ligands, CD80 and CD86, and in doing so, impairs de novo alloimmune responses. However, in most patients belatacept is ineffective in preventing allograft rejection when used as a monotherapy, and adjuvant therapy is required for control of costimulation-blockade resistant rejection (CoBRR). In rodent models, impaired access to secondary lymphoid tissues has been demonstrated to reduce alloimmune responses to vascularized allografts. Here we show that surgical maneuvers, lymphatic ligation, and splenectomy, designed to anatomically limit access to secondary lymphoid tissues, control CoBRR and facilitate belatacept monotherapy in a nonhuman primate model of kidney transplantation without adjuvant immunotherapy. We further demonstrate that animals sustained on belatacept monotherapy progressively develop an increasingly naïve T and B cell repertoire, an effect that is accelerated by splenectomy and lost at the time of belatacept withdrawal and rejection. These pilot data inform the role of secondary lymphoid tissues on the development of CoBRR and the use of costimulation molecule-focused therapies.
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Affiliation(s)
- Michael S Mulvihill
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Kannan P Samy
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Qimeng A Gao
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Robin Schmitz
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Robert P Davis
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Brian Ezekian
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Francis Leopardi
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Mingqing Song
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Tam How
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Kyha Williams
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Andrew Barbas
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Bradley Collins
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Allan D Kirk
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
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10
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Schroder PM, Fitch ZW, Schmitz R, Choi AY, Kwun J, Knechtle SJ. The past, present, and future of costimulation blockade in organ transplantation. Curr Opin Organ Transplant 2019; 24:391-401. [PMID: 31157670 PMCID: PMC7088447 DOI: 10.1097/mot.0000000000000656] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Manipulating costimulatory signals has been shown to alter T cell responses and prolong graft survival in solid organ transplantation. Our understanding of and ability to target various costimulation pathways continues to evolve. RECENT FINDINGS Since the approval of belatacept in kidney transplantation, many additional biologics have been developed targeting clinically relevant costimulation signaling axes including CD40-CD40L, inducible costimulator-inducible costimulator ligand (ICOS-ICOSL), and OX40-OX40L. Currently, the effects of costimulation blockade on posttransplant humoral responses, tolerance induction, and xenotransplantation are under active investigation. Here, we will discuss these pathways as well as preclinical and clinical outcomes of biologics targeting these pathways in organ transplantation. SUMMARY Targeting costimultion is a promising approach for not only controlling T cell but also B cell responses. Consequently, costimulation blockade shows considerable potential for improving outcomes in antibody-mediated rejection and xenotransplantation.
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Affiliation(s)
- Paul M. Schroder
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Zachary W. Fitch
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Robin Schmitz
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, North Carolina, USA
| | - Ashley Y. Choi
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, North Carolina, USA
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11
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Yamamoto T, Li Q, Hara H, Wang L, Zhou H, Li J, Eckhoff DE, Joseph Tector A, Klein EC, Lovingood R, Ezzelarab M, Ayares D, Wang Y, Cooper DKC, Iwase H. B cell phenotypes in baboons with pig artery patch grafts receiving conventional immunosuppressive therapy. Transpl Immunol 2018; 51:12-20. [PMID: 30092338 PMCID: PMC6249078 DOI: 10.1016/j.trim.2018.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND In the pig-to-baboon artery patch model with no immunosuppressive therapy, a graft from an α1,3-galactosyltransferase gene-knockout (GTKO) pig elicits a significant anti-nonGal IgG response, indicating sensitization to the graft. A costimulation blockade-based regimen, e.g., anti-CD154mAb or anti-CD40mAb, prevents sensitization. However, neither of these agents is currently FDA-approved. The aim of the present study was to determine the efficacy of FDA-approved agents on the T and B cell responses. METHODS Artery patch xenotransplantation in baboons was carried out using GTKO/CD46 pigs with (n = 2) or without (n = 1) the mutant transgene for CIITA-knockdown. Immunosuppressive therapy consisted of induction with ATG and anti-CD20mAb, and maintenance with different combinations of CTLA4-Ig, tacrolimus, and rapamycin. In addition, all 3 baboons received daily corticosteroids, the IL-6R blocker, tocilizumab, at regular intervals, and the TNF-α blocker, etanercept, for the first 2 weeks. Recipient blood was monitored for anti-nonGal antibody levels by flow cytometry (using GTKO/CD46 pig aortic endothelial cells), and mixed lymphocyte reaction (MLR). CD22+B cell profiles (naïve [IgD+/CD27-], non-switched memory [IgD+/CD27+], and switched memory [IgD-/CD27+] B cell subsets) were measured by flow cytometry. At 6 months, the baboons were euthanized and the grafts were examined histologically. RESULTS No elicited anti-pig antibodies developed in any baboon. The frequency of naïve memory B cells increased significantly (from 34% to 90%, p = 0.0015), but there was a significant decrease in switched memory B cells (from 17% to 0.5%, p = 0.015). MLR showed no increase in the proliferative T cell response in those baboons that had received CTLA4-Ig (n = 2). Histological examination showed few or no features of rejection in any graft. CONCLUSIONS The data suggest that immunosuppressive therapy with only FDA-approved agents may be adequate to prevent an adaptive immune response to a genetically-engineered pig graft, particularly if CTLA4-Ig is included in the regimen, in part because the development of donor-specific memory B cells is inhibited.
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Affiliation(s)
- Takayuki Yamamoto
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Qi Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - Hidetaka Hara
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Liaoran Wang
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - Hongmin Zhou
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Cardiothoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Juan Li
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - Devin E Eckhoff
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - A Joseph Tector
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Edwin C Klein
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ray Lovingood
- Kirklin Clinic Pharmacy, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mohamed Ezzelarab
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Yi Wang
- Second Affiliated Hospital, University of South China, Hengyang City, Hunan, China
| | - David K C Cooper
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Hayato Iwase
- Xenotransplantation Program, Department of Surgery, University of Alabama at Birmingham, Birmingham, AL, USA.
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Herrera-Gómez F, Del Aguila W, Tejero-Pedregosa A, Adler M, Padilla-Berdugo R, Maurtua-Briseño-Meiggs Á, Pascual J, Pascual M, San Segundo D, Heidt S, Álvarez FJ, Ochoa-Sangrador C, Lambert C. The number of FoxP3 regulatory T cells in the circulation may be a predictive biomarker for kidney transplant recipients: A multistage systematic review. Int Immunopharmacol 2018; 65:483-492. [PMID: 30390595 DOI: 10.1016/j.intimp.2018.10.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/10/2018] [Accepted: 10/19/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The kinetics of the FoxP3 regulatory T-cell (Treg) population in kidney transplant recipients (KTR) are related to the clinical effect of immunosuppression based on mammalian Target Of Rapamycin inhibitors (mTORi) with/without belatacept (predictive biomarker). METHODS A multistage systematic review of published and unpublished literature is presented [registration IDs in the International Prospective Register of Systematic Reviews (PROSPERO): CRD42017057570, CRD42018085019, CRD42018084941, CRD42018085186]. A multidisciplinary supervision mechanism for contextualizing of search findings was required. The peripheral blood immune cell phenotypes encompassing all regulatory cells in KTRs were assessed in order to suggest new markers of acute rejection-associated acute allograft dysfunction (AR/AAD) events in KTRs treated with mTORi alone or combined to belatacept. Quantitative estimates and evaluation of the body of evidence are provided. RESULTS An increase in Tregs and other regulatory cell types in the circulation in KTRs under mTORi with/without belatacept were observed. Patients with increased Tregs presented a low frequency of AR/AAD events compared to those in which the number of Tregs remained unchanged or even diminished [Odds Ratio (OR)/95% confidence interval (95% CI)/I2/number of studies (n): 0.31/0.10-0.93/0%/6]. Nevertheless, there are too few trials to consider Tregs in the circulation as a predictive biomarker. Inadequate reporting prevents appreciating clinical relevance in such studies. CONCLUSIONS Despite advances, clinical qualification of potential predictive biomarkers continues to be difficult. Clinical evidence on Tregs in KTRs needs to be enlarged. Biomarkers should be able to evaluate the effect of medicines targeted to specific patient populations.
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Affiliation(s)
- Francisco Herrera-Gómez
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Valladolid, Valladolid, Spain; Department of Nephrology, Hospital Virgen de la Concha, Sanidad de Castilla y León, Zamora, Spain.
| | | | - Armando Tejero-Pedregosa
- Intensive Care Medicine, Hospital Virgen de la Concha, Sanidad de Castilla y León, Zamora, Spain
| | - Marcel Adler
- Hematology, University Hospital of Basel, Basel, Switzerland
| | - Rosario Padilla-Berdugo
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Valladolid, Valladolid, Spain
| | | | | | - Manuel Pascual
- Centre de Transplantation d'Organes, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
| | - David San Segundo
- Immunology, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
| | - Sebastiaan Heidt
- Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands.
| | - F Javier Álvarez
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Valladolid, Valladolid, Spain; CEIm Área de Salud Valladolid Este, Hospital Clínico Universitario de Valladolid, Valladolid, Spain.
| | | | - Claude Lambert
- Immunology, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Priest-en-Jarez, France
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Kwun J, Park J, Yi JS, Farris AB, Kirk AD, Knechtle SJ. IL-21 Biased Alemtuzumab Induced Chronic Antibody-Mediated Rejection Is Reversed by LFA-1 Costimulation Blockade. Front Immunol 2018; 9:2323. [PMID: 30374350 PMCID: PMC6196291 DOI: 10.3389/fimmu.2018.02323] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/18/2018] [Indexed: 11/25/2022] Open
Abstract
Despite its excellent efficacy in controlling T cell mediated acute rejection, lymphocyte depletion may promote a humoral response. While T cell repopulation after depletion has been evaluated in many aspects, the B cell response has not been fully elucidated. We tested the hypothesis that the mechanisms also involve skewed T helper phenotype after lymphocytic depletion. Post-transplant immune response was measured from alemtuzumab treated hCD52Tg cardiac allograft recipients with or without anti-LFA-1 mAb. Alemtuzumab induction promoted serum DSA, allo-B cells, and CAV in humanized CD52 transgenic (hCD52Tg) mice after heterotopic heart transplantation. Additional anti-LFA-1 mAb treatment resulted in reduced DSA (Fold increase 4.75 ± 6.9 vs. 0.7 ± 0.5; p < 0.01), allo-specific B cells (0.07 ± 0.06 vs. 0.006 ± 0.002 %; p < 0.01), neo-intimal hyperplasia (56 ± 14% vs. 23 ± 13%; p < 0.05), arterial disease (77.8 ± 14.2 vs. 25.8 ± 20.1%; p < 0.05), and fibrosis (15 ± 23.3 vs. 4.3 ± 1.65%; p < 0.05) in this alemtuzumab-induced chronic antibody-mediated rejection (CAMR) model. Surprisingly, elevated serum IL-21 levels in alemtuzumab-treated mice was reduced with LFA-1 blockade. In accordance with the increased serum IL-21 level, alemtuzumab treated mice showed hyperplastic germinal center (GC) development, while the supplemental anti-LFA-1 mAb significantly reduced the GC frequency and size. We report that the incomplete T cell depletion inside of the GC leads to a systemic IL-21 dominant milieu with hyperplastic GC formation and CAMR. Conventional immunosuppression, such as tacrolimus and rapamycin, failed to reverse AMR, while co-stimulation blockade with LFA-1 corrected the GC hyperplastic response. The identification of IL-21 driven chronic AMR elucidates a novel mechanism that suggests a therapeutic approach with cytolytic induction.
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Affiliation(s)
- Jean Kwun
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, NC, United States
| | - Jaeberm Park
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, NC, United States
| | - John S Yi
- Division of Surgical Sciences, Department of Surgery, Duke University Medical Center, Durham, NC, United States
| | - Alton B Farris
- Department of Pathology, Emory University School of Medicine, Atlanta, GA, United States
| | - Allan D Kirk
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, NC, United States
| | - Stuart J Knechtle
- Department of Surgery, Duke Transplant Center, Duke University Medical Center, Durham, NC, United States
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14
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Zwang NA, Ganesh BB, Cardenas KT, Chong AS, Finn PW, Perkins DL. An optimized protocol to quantify signaling in human transitional B cells by phospho flow cytometry. J Immunol Methods 2018; 463:112-121. [PMID: 30321549 DOI: 10.1016/j.jim.2018.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/10/2018] [Accepted: 10/03/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Phospho flow cytometry is a powerful technique to analyze signaling in rare cell populations. This technique, however, requires harsh conditions for cell fixation and permeabilization, which can denature surface antigens or antibody-conjugated fluorochromes. These are among several technical limitations which have been a barrier to quantify signaling in unique B cell subsets. One such immature subset, transitional B cells (TrBs), may play a role in suppressing solid organ transplant rejection, graft-versus-host disease, autoimmunity, and even the immune response to malignancy. Here we sought to optimize a protocol for quantification of signaling in human TrBs compared with mature B cell subsets. RESULTS TrBs were defined by surface marker expression as CD19+CD24hiCD38hi. Key parameters optimized included antibody clone selection, sequence of surface epitope labeling in relation to paraformaldehyde-based fixation and methanol-based permeabilization, photomultiplier tube (PMT) voltages, and compensation. Special attention was paid to labeling of CD38 with regard to these parameters, and an optimized protocol enabled reliable identification of TrBs, naïve (CD24+CD38+), early memory (CD24hiCD38-), and late memory (CD24-CD38-) B cells. Phospho flow cytometry enabled simultaneous quantification of phosphorylation among at least three different signaling molecules within the same sample. Among normal donors, transitional B cells exhibited diminished mitogen activated protein kinase/extracellular signal-regulated kinase and Akt phospho signaling upon nonspecific stimulation with phorbol 12-myristate 13-acetateand ionomycin stimulation. CONCLUSIONS We optimized an effective protocol to quantify B cell subset signaling upon stimulation. Such a protocol may ultimately serve as the basis for assessing dysfunctional B cell signaling in disease, predict clinical outcomes, and monitor response to B cell-directed therapies.
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Affiliation(s)
- Nicholas A Zwang
- Division of Nephrology, Department of Medicine, The University of Illinois at Chicago, 820 South Wood Street (MC 793), Chicago, IL 60612, USA.
| | - Balaji B Ganesh
- Flow Cytometry Core, The University of Illinois at Chicago, Medical Science Building, 835 South Wolcott Avenue (E-25C), Chicago, IL 60612, USA
| | - Kim T Cardenas
- BioLegend, 9727 Pacific Heights Blvd, San Diego, CA 92121, USA
| | - Anita S Chong
- Department of Surgery, Section of Transplantation Surgery, The University of Chicago, 5841 South Maryland Avenue (SBRI J547/MC 5026), Chicago, IL 60637, USA
| | - Patricia W Finn
- Department of Medicine, The University of Illinois at Chicago, 840 South Wood Street Suite 1020N (MC 787), Chicago, IL 60612, USA
| | - David L Perkins
- Division of Nephrology, Department of Medicine, The University of Illinois at Chicago, 820 South Wood Street (MC 793), Chicago, IL 60612, USA
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15
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16
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Espinosa JR, Mou D, Adams BW, DiBernardo LR, MacDonald AL, McRae M, Miller AN, Song M, Stempora LL, Wang J, Iwakoshi NN, Kirk AD. T Cell Repertoire Maturation Induced by Persistent and Latent Viral Infection Is Insufficient to Induce Costimulation Blockade Resistant Organ Allograft Rejection in Mice. Front Immunol 2018; 9:1371. [PMID: 29963060 PMCID: PMC6013589 DOI: 10.3389/fimmu.2018.01371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 06/01/2018] [Indexed: 12/22/2022] Open
Abstract
CD28:CD80/86 pathway costimulation blockade (CoB) with the CD80/86-specific fusion protein CTLA4-Ig prevents T cell-mediated allograft rejection in mice. However, in humans, transplantation with CoB has been hampered by CoB-resistant rejection (CoBRR). CoBRR has been attributed in part to pathogen-driven T cell repertoire maturation and resultant heterologous alloreactive memory. This has been demonstrated experimentally in mice. However, prior murine models have used viral pathogens, CoB regimens, graft types, and/or antigen systems atypically encountered clinically. We therefore sought to explore whether CoBRR would emerge in a model of virus-induced memory differentiation designed to more closely mimic clinical conditions. Specifically, we examined mouse homologs of clinically prevalent viruses including murine polyomavirus, cytomegalovirus, and gammaherpesvirus 68 in the presence of clinically relevant maintenance CoB regimens using a fully MHC-mismatched, vascularized allograft model. Infected mice developed a significant, sustained increase in effector memory T cells consistent with that seen in humans, but neither developed heterologous alloreactivity nor rejected primarily vascularized heterotopic heart transplants at an increased rate compared with uninfected mice. These results indicate that memory acquisition alone is insufficient to provoke CoBRR and suggest that knowledge of prior latent or persistent viral infection may have limited utility in anticipating heterologous CoB-resistant alloimmunity.
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Affiliation(s)
- Jaclyn R Espinosa
- Department of Surgery, Emory University, Atlanta, GA, United States.,Department of Surgery, Duke University, Durham, NC, United States
| | - Danny Mou
- Department of Surgery, Emory University, Atlanta, GA, United States
| | - Bartley W Adams
- Department of Surgery, Duke University, Durham, NC, United States
| | | | | | - MacKenzie McRae
- Department of Surgery, Duke University, Durham, NC, United States
| | - Allison N Miller
- Department of Surgery, Duke University, Durham, NC, United States
| | - Mingqing Song
- Department of Surgery, Duke University, Durham, NC, United States
| | - Linda L Stempora
- Department of Surgery, Duke University, Durham, NC, United States
| | - Jun Wang
- Department of Surgery, Duke University, Durham, NC, United States
| | - Neal N Iwakoshi
- Department of Surgery, Emory University, Atlanta, GA, United States
| | - Allan D Kirk
- Department of Surgery, Duke University, Durham, NC, United States
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17
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Xu H, Bendersky VA, Brennan TV, Espinosa JR, Kirk AD. IL-7 receptor heterogeneity as a mechanism for repertoire change during postdepletional homeostatic proliferation and its relation to costimulation blockade-resistant rejection. Am J Transplant 2018; 18:720-730. [PMID: 29136317 PMCID: PMC6035390 DOI: 10.1111/ajt.14589] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 10/08/2017] [Accepted: 11/04/2017] [Indexed: 01/25/2023]
Abstract
Kidney transplant patients treated with belatacept without depletional induction experience higher rates of acute rejection compared to patients treated with conventional immunosuppression. Costimulation blockade-resistant rejection (CoBRR) is associated with terminally differentiated T cells. Alemtuzumab induction and belatacept/sirolimus immunotherapy effectively prevent CoBRR. We hypothesized that cells in late phases of differentiation would be selectively less capable than more naive phenotypes of repopulating postdepletion, providing a potential mechanism by which lymphocyte depletion and repopulation could reduce the risk of CoBRR. Lymphocytes from 20 recipients undergoing alemtuzumab-induced depletion and belatacept/sirolimus immunosuppression were studied longitudinally for markers of maturation (CCR7, CD45RA, CD57, PD1), recent thymic emigration (CD31), and the IL-7 receptor-α (IL-7Rα). Serum was analyzed for IL-7. Alemtuzumab induction produced profound lymphopenia followed by repopulation, during which naive IL-7Rα+ CD57- PD1- cells progressively became the predominant subset. This did not occur in a comparator group of 10 patients treated with conventional immunosuppression. Serum from depleted patients showed markedly elevated IL-7 levels posttransplantation. Sorted CD57- PD1- cells demonstrated robust proliferation in response to IL-7, whereas more differentiated cells proliferated poorly. These data suggest that differences in IL-7-dependent proliferation is one exploitable mechanism that distinguishes CoB-sensitive and CoB-resistant T cell populations to reduce the risk of CoBRR. (ClinicalTrials.gov - NCT00565773.).
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Affiliation(s)
- He Xu
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | | | - Todd V Brennan
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Jaclyn R Espinosa
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
| | - Allan D Kirk
- Department of Surgery, Duke University Medical Center, Durham, NC, USA
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18
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Nicosia M, Valujskikh A. Total Recall: Can We Reshape T Cell Memory by Lymphoablation? Am J Transplant 2017; 17:1713-1718. [PMID: 27888576 DOI: 10.1111/ajt.14144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/01/2016] [Accepted: 11/15/2016] [Indexed: 01/25/2023]
Abstract
Despite recent advances in immunosuppression, donor-reactive memory T cells remain a serious threat to successful organ transplantation. To alleviate damaging effects of preexisting immunologic memory, lymphoablative induction therapies are used as part of standard care in sensitized recipients. However, accumulating evidence suggests that memory T cells have advantages over their naive counterparts in surviving depletion and expanding under lymphopenic conditions. This may at least partially explain the inability of existing lymphoablative strategies to improve long-term allograft outcome in sensitized recipients, despite the well-documented decrease in the frequency of early acute rejection episodes. This minireview summarizes the insights gained from both experimental and clinical transplantation as to the effects of existing lymphoablative strategies on memory T cells and discusses the latest research developments aimed at improving the efficacy and safety of lymphoablation.
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Affiliation(s)
- M Nicosia
- Glickman Urological Institute and Department of Immunology, Cleveland Clinic, Cleveland, OH
| | - A Valujskikh
- Glickman Urological Institute and Department of Immunology, Cleveland Clinic, Cleveland, OH
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Abstract
Crosstalk between B and T cells in transplantation is increasingly recognized as being important in the alloimmune response. T cell activation of B cells occurs by a 3-stage pathway, culminating with costimulation signals. We review the distinct T cell subtypes required for B-cell activation and discuss the formation of the germinal center (GC) after transplantation, with particular reference to the repopulation of the GC after depletional induction, and the subsequent effect of immunosuppressive manipulation of T cell-B cell interactions. In addition, ectopic GCs are seen in transplantation, but their role is not fully understood. Therapeutic options to target T cell-B cell interactions are of considerable interest, both as immunosuppressive tools, and to aid in the further understanding of these important alloimmune mechanisms.
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20
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Rapamycin safeguards lymphocytes from DNA damage accumulation in vivo. Eur J Cell Biol 2016; 95:331-41. [PMID: 27349711 DOI: 10.1016/j.ejcb.2016.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 06/07/2016] [Accepted: 06/14/2016] [Indexed: 12/29/2022] Open
Abstract
Several studies reported the benefits of switching from anticalcineurins to mTOR inhibitors to avoid cancer occurrence after organ transplantation. The purpose of our study was to determine in vivo biological markers to explain these benefits. Cellular changes related to cellular senescence and DNA damage were analyzed in peripheral blood lymphocytes. Thirty-five kidney transplanted patients receiving anticalcineurins were investigated: 17 patients were proposed to switch to rapamycin and 18 patients with similar age and transplantation duration, continued anticalcineurins. Rapamycin effects were studied one year after the switch. Thirteen healthy volunteers and 18 hemodialyzed patients were evaluated as control. Compared with the healthy group, hemodialyzed and transplanted patients exhibited a significant decrease in telomere length, an increase in p16(INK4A) mRNA expression and in lymphocytes with 53BP1 foci. A destabilization of the shelterin complexes was suggested by a significant TIN2 mRNA decrease in transplanted patients compared with controls and a significant increase in TRF1, TRF2 and POT1 expression in switch-proposed patients compared with the non-switched subgroup. Rapamycin treatment resulted in a significant decrease in DNA damage and a slight TIN2 increase. In vitro experiments strengthened in vivo results showing that rapamycin but not FK506 induced a significant DNA damage decrease and TIN2 expression increase compared with controls. The roles of rapamycin in the decrease in DNA damage in vivo and the rescue of shelterin gene expression are demonstrated for the first time. These data provide new insights into understanding of how rapamycin may overcome genomic injuries.
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Abstract
Antigen-experienced T cells, also known as memory T cells, are functionally and phenotypically distinct from naive T cells. Their enhanced expression of adhesion molecules and reduced requirement for co-stimulation enables them to mount potent and rapid recall responses to subsequent antigen encounters. Memory T cells generated in response to prior antigen exposures can cross-react with other nonidentical, but similar, antigens. This heterologous cross-reactivity not only enhances protective immune responses, but also engenders de novo alloimmunity. This latter characteristic is increasingly recognized as a potential barrier to allograft acceptance that is worthy of immunotherapeutic intervention, and several approaches have been investigated. Calcineurin inhibition effectively controls memory T-cell responses to allografts, but this benefit comes at the expense of increased infectious morbidity. Lymphocyte depletion eliminates allospecific T cells but spares memory T cells to some extent, such that patients do not completely lose protective immunity. Co-stimulation blockade is associated with reduced adverse-effect profiles and improved graft function relative to calcineurin inhibition, but lacks efficacy in controlling memory T-cell responses. Targeting the adhesion molecules that are upregulated on memory T cells might offer additional means to control co-stimulation-blockade-resistant memory T-cell responses.
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