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Abstract
Exhaustion of T cells occurs in response to long-term exposure to self and foreign antigens. It limits T cell capacity to proliferate and produce cytokines, leading to an impaired ability to clear chronic infections or eradicate tumors. T-cell exhaustion is associated with a specific transcriptional, epigenetic, and metabolic program and characteristic cell surface markers' expression. Recent studies have begun to elucidate the role of T-cell exhaustion in transplant. Higher levels of exhausted T cells have been associated with better graft function in kidney transplant recipients. In contrast, reinvigorating exhausted T cells by immune checkpoint blockade therapies, while promoting tumor clearance, increases the risk of acute rejection. Lymphocyte depletion and high alloantigen load have been identified as major drivers of T-cell exhaustion. This could account, at least in part, for the reduced rates of acute rejection in organ transplant recipients induced with thymoglobulin and for the pro-tolerogenic effects of a large organ such as the liver. Among the drugs that are widely used for maintenance immunosuppression, calcineurin inhibitors have a contrasting inhibitory effect on exhaustion of T cells, while the influence of mTOR inhibitors is still unclear. Harnessing or encouraging the natural processes of exhaustion may provide a novel strategy to promote graft survival and transplantation tolerance.
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Tackling cancer cell dormancy: Insights from immune models, and transplantation. Semin Cancer Biol 2021; 78:5-16. [PMID: 33582171 DOI: 10.1016/j.semcancer.2021.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/06/2021] [Accepted: 02/03/2021] [Indexed: 02/07/2023]
Abstract
Disseminated non-dividing (dormant) cancer cells as well as those in equilibrium with the immune response remain the major challenge for successful treatment of cancer. The equilibrium between disseminated dormant cancer cells and the immune system is reminiscent of states that can occur during infection or allogeneic tissue and cell transplantation. We discuss here the major competing models of how the immune system achieves a self nonself discrimination (pathogen/danger patterns, quorum, and coinhibition/tuning models), and suggest that taking advantage of a combination of the proposed mechanisms in each model may lead to increased efficacy in tackling cancer cell dormancy.
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Kleef R, Nagy R, Baierl A, Bacher V, Bojar H, McKee DL, Moss R, Thoennissen NH, Szász M, Bakacs T. Low-dose ipilimumab plus nivolumab combined with IL-2 and hyperthermia in cancer patients with advanced disease: exploratory findings of a case series of 131 stage IV cancers - a retrospective study of a single institution. Cancer Immunol Immunother 2020; 70:1393-1403. [PMID: 33151369 PMCID: PMC8053148 DOI: 10.1007/s00262-020-02751-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 10/14/2020] [Indexed: 02/07/2023]
Abstract
The 3-year overall survival (OS) rate of patients with previously treated or untreated stage III or IV melanoma has by now reached 63% using ipilimumab and nivolumab therapy. However, immune-related adverse events (irAEs) of grade 3 or 4 occurred in 59% of patients leading to discontinuation of therapy in 24.5% of patients and one death. Therapy with checkpoint inhibitors could be safer and more effective in combination with hyperthermia and fever inducing therapies. We conducted a retrospective analysis to test the safety and efficacy of a new combination immune therapy in 131 unselected stage IV solid cancer patients with 23 different histological types of cancer who exhausted all conventional treatments. Treatment consisted of locoregional- and whole-body hyperthermia, individually dose adapted interleukin 2 (IL-2) combined with low-dose ipilimumab (0.3 mg/kg) plus nivolumab (0.5 mg/kg). The objective response rate (ORR) was 31.3%, progression-free survival (PFS) was 10 months, survival probabilities at 6 months was 86.7% (95% CI, 81.0–92.8%), at 9 months was 73.5% (95% CI, 66.2–81.7%), at 12 months was 66.5% (95% CI, 58.6–75.4%), while at 24 months survival was 36.6% (95% CI:28.2%; 47.3%). irAEs of World Health Organization (WHO) Toxicity Scale grade 1, 2, 3, and 4 were observed in 23.66%, 16.03%, 6.11%, and 2.29% of patients, respectively. Our results suggest that the irAEs profile of the combined treatment is safer than that of the established protocols without compromising efficacy.
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Affiliation(s)
- R Kleef
- Immunology and Integrative Oncology, Auhofstraße 1, 1130, Vienna, Austria
| | - R Nagy
- Immunology and Integrative Oncology, Auhofstraße 1, 1130, Vienna, Austria
| | - A Baierl
- Department of Statistic and Operations Research, University of Vienna, Oskar-Morgenstern-Platz 1, 1090, Vienna, Austria
| | - V Bacher
- Immunology and Integrative Oncology, Auhofstraße 1, 1130, Vienna, Austria
| | - H Bojar
- NextGen Oncology, Dusseldorf, Germany
| | - D L McKee
- Integrative Cancer Consulting, Aptos, CA, USA
| | - R Moss
- Moss Reports, 104 Main Street, Unit 1422, Blue Hill, ME, 04614-1422, USA
| | - N H Thoennissen
- Oncology Center at Lenbachplatz, Ottostr. 3, 80333, Munich, Germany
| | - M Szász
- Cancer Centre, Semmelweis University, 1083, Budapest, Hungary
| | - T Bakacs
- PRET Therapeutics Ltd, 1124, Budapest, Hungary.
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Symonds AL, Zheng W, Miao T, Wang H, Wang T, Kiome R, Hou X, Li S, Wang P. Egr2 and 3 control inflammation, but maintain homeostasis, of PD-1 high memory phenotype CD4 T cells. Life Sci Alliance 2020; 3:3/9/e202000766. [PMID: 32709717 PMCID: PMC7391068 DOI: 10.26508/lsa.202000766] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 01/13/2023] Open
Abstract
PD-1high memory CD4 T cells are pathogenic in autoimmune disease; here they show their expression of Egr2 is defective in rheumatoid arthritis and Egr2 & 3 control their inflammation and homeostasis. The transcription factors Egr2 and 3 are essential for controlling inflammatory autoimmune responses of memory phenotype (MP) CD4 T cells. However, the mechanism is still unclear. We have now found that the Egr2+ subset (PD-1high MP) of MP CD4 T cells expresses high levels of checkpoint molecules (PD-1 and Lag3) and also markers of effector T cells (CXCR3 and ICAM-1). Egr2/3 are not required for PD-1high MP CD4 cell development but mediate a unique transcriptional programme that effectively controls their inflammatory responses, while promoting homeostatic proliferation and adaptive responses. Egr2 negative PD-1high MP CD4 T cells are impaired in homeostatic proliferation and adaptive responses against viral infection but display inflammatory responses to innate stimulation such as IL-12. PD-1high MP CD4 T cells have recently been implicated in rheumatoid arthritis pathogenesis, and we have now found that Egr2 expression is reduced in PD-1high MP CD4 T cells from patients with active rheumatoid arthritis compared with healthy controls. These findings demonstrate that Egr2/3 control the inflammatory responses of PD-1high MP CD4 T cells and maintain their adaptive immune fitness.
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Affiliation(s)
- Alistair Lj Symonds
- The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Wei Zheng
- Division of Rheumatology, Dong Fang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Tizong Miao
- The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Haiyu Wang
- Division of Rheumatology, Dong Fang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - TieShang Wang
- Division of Rheumatology, Dong Fang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Ruth Kiome
- Bioscience, Brunel University, Uxbridge, UK
| | - Xiujuan Hou
- Division of Rheumatology, Dong Fang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Suling Li
- Bioscience, Brunel University, Uxbridge, UK
| | - Ping Wang
- The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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Fisher J, Zeitouni N, Fan W, Samie FH. Immune checkpoint inhibitor therapy in solid organ transplant recipients: A patient-centered systematic review. J Am Acad Dermatol 2020; 82:1490-1500. [DOI: 10.1016/j.jaad.2019.07.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/12/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023]
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Kerepesi C, Bakacs T, Moss RW, Slavin S, Anderson CC. Significant association between tumor mutational burden and immune-related adverse events during immune checkpoint inhibition therapies. Cancer Immunol Immunother 2020; 69:683-687. [PMID: 32152702 PMCID: PMC7183506 DOI: 10.1007/s00262-020-02543-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/21/2020] [Indexed: 12/19/2022]
Abstract
More than 2000 immuno-oncology agents are being tested or are in use as a result of the cancer immunotherapy revolution. Manipulation of co-inhibitory receptors has achieved tumor eradication in a minority of patients, but widespread immune-related adverse events (irAEs) compromised tolerance to healthy self-tissues in the majority. We have proposed that a major mechanism of irAEs is similar to a graft-versus-malignancy effect of graft-versus-host disease. To verify our hypothesis, we retrieved post-marketing data of adverse events from the U.S. Food and Drug Administration Adverse Event Reporting System. A significant positive correlation was revealed in 7677 patients between the reporting odds ratio of irAEs during immune checkpoint inhibitor therapy and the corresponding tumor mutational burden across 19 cancer types. These results can be interpreted to mean that the ICI drugs unleashed T cells against “altered-self,” self, and tumors resulting in better overall survival.
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Affiliation(s)
- Csaba Kerepesi
- Institute for Computer Science and Control (SZTAKI), Kende u 13-17, Budapest, 1111, Hungary.
- Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA.
| | | | - Ralph W Moss
- Moss Reports, 104 Main Street Unit 1422, Blue Hill, ME, 04614-1422, USA
| | - Shimon Slavin
- Biotherapy International, The Center for Innovative Cancer Immunotherapy and Cellular Medicine, Weizmann Center, 14 Weizmann Street Floor 15, Suite 1503, 64239, Tel Aviv, Israel
| | - Colin C Anderson
- Departments of Surgery and Medical Microbiology and Immunology, Alberta Diabetes Institute, Alberta Transplant Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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Yeung MY, Grimmig T, Sayegh MH. Costimulation Blockade in Transplantation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1189:267-312. [PMID: 31758538 DOI: 10.1007/978-981-32-9717-3_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
T cells play a pivotal role in orchestrating immune responses directed against a foreign (allogeneic) graft. For T cells to become fully activated, the T-cell receptor (TCR) must interact with the major histocompatibility complex (MHC) plus peptide complex on antigen-presenting cells (APCs), followed by a second "positive" costimulatory signal. In the absence of this second signal, T cells become anergic or undergo deletion. By blocking positive costimulatory signaling, T-cell allo-responses can be aborted, thus preventing graft rejection and promoting long-term allograft survival and possibly tolerance (Alegre ML, Najafian N, Curr Mol Med 6:843-857, 2006; Li XC, Rothstein DM, Sayegh MH, Immunol Rev 229:271-293, 2009). In addition, costimulatory molecules can provide negative "coinhibitory" signals that inhibit T-cell activation and terminate immune responses; strategies to promote these pathways can also lead to graft tolerance (Boenisch O, Sayegh MH, Najafian N, Curr Opin Organ Transplant 13:373-378, 2008). However, T-cell costimulation involves an incredibly complex array of interactions that may act simultaneously or at different times in the immune response and whose relative importance varies depending on the different T-cell subsets and activation status. In transplantation, the presence of foreign alloantigen incites not only destructive T effector cells but also protective regulatory T cells, the balance of which ultimately determines the fate of the allograft (Lechler RI, Garden OA, Turka LA, Nat Rev Immunol 3:147-158, 2003). Since the processes of alloantigen-specific rejection and regulation both require activation of T cells, costimulatory interactions may have opposing or synergistic roles depending on the cell being targeted. Such complexities present both challenges and opportunities in targeting T-cell costimulatory pathways for therapeutic purposes. In this chapter, we summarize our current knowledge of the various costimulatory pathways in transplantation and review the current state and challenges of harnessing these pathways to promote graft tolerance (summarized in Table 10.1).
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Affiliation(s)
- Melissa Y Yeung
- Department of Medicine, Renal Division, Brigham and Women's Hospital, Boston, MA, USA. .,Harvard Medical School, Boston, MA, USA.
| | - Tanja Grimmig
- Department of Surgery, Molecular Oncology and Immunology, University of Wuerzburg, Wuerzburg, Germany
| | - Mohamed H Sayegh
- Department of Medicine, Renal Division, Brigham and Women's Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA.,Department of Medicine and Immunology, American University of Beirut, Beirut, Lebanon
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Bakacs T, Moss RW, Kleef R, Szasz MA, Anderson CC. Exploiting autoimmunity unleashed by low-dose immune checkpoint blockade to treat advanced cancer. Scand J Immunol 2019; 90:e12821. [PMID: 31589347 DOI: 10.1111/sji.12821] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/31/2019] [Accepted: 08/26/2019] [Indexed: 12/15/2022]
Abstract
As a result of the cancer immunotherapy revolution, more than 2000 immuno-oncology agents are currently being tested or are in use to improve responses. Not unexpectedly, the 2018 Nobel Prize in Physiology or Medicine was awarded to James P. Allison and Tasuku Honjo for their development of cancer therapy by the blockade of co-inhibitory signals. Unfortunately, manipulation of the co-inhibitory receptors has also resulted in a safety issue: widespread iatrogenic immune-related adverse events (irAEs). Autoimmunity is emerging as the nemesis of immunotherapy. Originally, it was assumed that CTLA-4 blockade selectively targets T cells relevant to the antitumour immune response. However, an uncontrolled pan T cell activation was induced compromising tolerance to healthy self-tissues. The irAEs are very similar to that of a chronic graft-versus-host-disease (GVHD) reaction following allogeneic bone marrow transplantation (BMT). We hypothesized that ipilimumab induced a graft-versus-malignancy (GVM) effect, which eradicated metastatic melanoma in a minority of patients, but also involved an auto-GVHD reaction that resulted in widespread autoimmunity in the majority. Therefore, we argued for a profound theoretical point against the consensus of experts. The task is not to desperately put the genie back in the bottle by immune-suppressive treatments, but instead to harness the autoimmune forces. In this way, the same goal could be achieved by an antibody as by the adoptive transfer of alloreactive donor lymphocytes, but without severe GVHD. The proof-of-principle of a low-dose-combination immune checkpoint therapy, consisting only of approved drugs and treatments, was demonstrated in 111 stage IV cancer patients.
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Affiliation(s)
| | | | - Ralf Kleef
- Immunology & Integrative Oncology, Kleef Hyperthermie, Vienna, Austria
| | | | - Colin C Anderson
- Departments of Surgery and Medical Microbiology & Immunology, Alberta Diabetes Institute, Alberta Transplant Institute, University of Alberta, Edmonton, Alberta, Canada
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Grant MJ, DeVito N, Salama AKS. Checkpoint inhibitor use in two heart transplant patients with metastatic melanoma and review of high-risk populations. Melanoma Manag 2018; 5:MMT10. [PMID: 30459942 PMCID: PMC6240846 DOI: 10.2217/mmt-2018-0004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 08/03/2018] [Indexed: 12/12/2022] Open
Abstract
Due to the unique side-effect profile of immune checkpoint inhibitors (ICIs), groups of patients deemed to be at high risk of complications were excluded from trials that proved the efficacy and safety of these agents in patients with various malignancies. Among these excluded patients were those with prior solid organ transplantation, chronic viral infections and pre-existing autoimmune diseases including paraneoplastic syndromes. We present follow-up on a patient from a previously published case report with an orthotopic heart transplantation who was treated with both cytotoxic T-lymphocyte antigen 4 and PD-1 inhibition safely, without organ rejection. Additionally, we describe the case of a patient with a cardiac allograft who also did not experience organ rejection after treatment with pembrolizumab. Through smaller trials, retrospective analyses, case series and individual case reports, we are accumulating initial data on how these agents are tolerated by the aforementioned groups. Our survey of the literature has found more evidence of organ transplant rejection in patients treated with PD-1 inhibitors than those treated with inhibitors of cytotoxic T-lymphocyte antigen 4. Patients with chronic viral infections, especially hepatitis C, seem to have little to no risk of treatment-related increase in serum RNA levels. The literature contains few documented cases of devastating exacerbations of pre-existing autoimmune disease during treatment with ICIs, and flares seem to be easily controlled by immunosuppression in the vast majority of cases. Last, several cases allude to a promising role for disease-specific antibodies and other serum biomarkers in identifying patients at high risk of developing certain immune-related adverse events, detecting subclinical immune-related adverse event onset, and monitoring treatment response to immunosuppressive therapy in patients treated with ICIs. Though these excluded populations have not been well studied in randomized placebo-controlled trials, we may be able to learn and derive hypotheses from the existing observational data in the literature.
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Affiliation(s)
- Michael J Grant
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.,Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Nicholas DeVito
- Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA
| | - April K S Salama
- Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Duke University Medical Center, Durham, NC, USA
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10
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Shahbazi M, Soltanzadeh-Yamchi M, Mohammadnia-Afrouzi M. T cell exhaustion implications during transplantation. Immunol Lett 2018; 202:52-58. [PMID: 30130559 DOI: 10.1016/j.imlet.2018.08.003] [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: 04/21/2018] [Revised: 08/05/2018] [Accepted: 08/16/2018] [Indexed: 12/20/2022]
Abstract
Exhaustion of lymphocyte function, particularly T cell exhaustion, due to prolonged exposure to a high load of foreign antigen is commonly seen during chronic viral infection as well as antitumor immune responses. This phenomenon has been associated with a determined molecular mechanism and phenotypic manifestations on the cell surface. In spite of investigation of exhaustion, mostly about CD8 responses toward viral infections, recent studies have reported that chronic exposure to antigen may develop exhaustion in CD4 + T cells, B cells, and NK cells. Little is known with respect to lymphocyte exhaustion during transplantation and its effect on aberrant anti-graft responses. Through a same mechanobiology observed during chronic exposure of foreign viral antigens, alloantigen persistence mediated by allograft could develop a favorable circumstance for exhaustion of T cells responding to allograft. However, to achieve better manipulation approaches of this event to reduce the complications during transplantation, we need to be armed with a bulk of knowledge with regard to quality and quantity of T cell exhaustion occurring in various allografts, the kinetics of exhaustion development, the impression of immunosuppressive agents on the exhaustion, and the influence of exhaustion on graft survival and immune tolerance.
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Affiliation(s)
- Mehdi Shahbazi
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Immunoregulation Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Department of Immunology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Mehdi Soltanzadeh-Yamchi
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Department of Immunology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Mousa Mohammadnia-Afrouzi
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Immunoregulation Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; Department of Immunology, School of Medicine, Babol University of Medical Sciences, Babol, Iran.
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Kwatra V, Karanth NV, Priyadarshana K, Charakidis M. Pembrolizumab for metastatic melanoma in a renal allograft recipient with subsequent graft rejection and treatment response failure: a case report. J Med Case Rep 2017; 11:73. [PMID: 28315636 PMCID: PMC5357565 DOI: 10.1186/s13256-017-1229-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 02/01/2017] [Indexed: 12/16/2022] Open
Abstract
Background Transplant patients were excluded from the pivotal phase III trials of checkpoint inhibitors in metastatic melanoma. The efficacy and toxicity profiles of checkpoint inhibitors in this cohort of patients are not well described. To the best of our knowledge, this is the first case report of a renal transplant patient with stage IV melanoma treated with a programmed cell death protein 1 checkpoint inhibitor that led to both treatment failure and renal graft rejection. Case presentation We present a case of a 58-year-old white man with a long-standing cadaveric renal transplant who was diagnosed with a B-Raf Proto-Oncogene, Serine/Threonine Kinase wild-type metastatic melanoma. He was treated with first-line pembrolizumab but experienced subsequent graft failure and rapid disease progression. Conclusions This case highlights the risks associated with the administration of checkpoint inhibitors in patients with a renal transplant and on immunosuppressive therapy. More specifically, it adds to the literature indicating that, compared with the cytotoxic T-lymphocyte-associated protein 4 inhibitor ipilimumab, anti-programmed cell death protein 1 agents are more likely to lead to renal graft failure. Additionally, these novel immunotherapeutics may be ineffective in transplant patients; therefore, clinicians should be very aware of those risks and carefully consider selection of agents and full disclosure of the risks to their patients.
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Affiliation(s)
- Vineet Kwatra
- Medical Oncology Department, Alan Walker Cancer Centre, Royal Darwin Hospital, 105 Rocklands Drive, Tiwi, NT, 0810, Australia.
| | - Narayan V Karanth
- Medical Oncology Department, Alan Walker Cancer Centre, Royal Darwin Hospital, 105 Rocklands Drive, Tiwi, NT, 0810, Australia
| | - Kelum Priyadarshana
- NT Renal Services, Royal Darwin Hospital, Darwin, NT, Australia.,Flinders University, Adelaide, SA, Australia
| | - Michail Charakidis
- Medical Oncology Department, Alan Walker Cancer Centre, Royal Darwin Hospital, 105 Rocklands Drive, Tiwi, NT, 0810, Australia
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Abstract
PURPOSE OF REVIEW The role of T-cell exhaustion in the failure of clearance of viral infections and tumors is well established. There are several ongoing trials to reverse T-cell exhaustion for treatment of chronic viral infections and tumors. The mechanisms leading to T-cell exhaustion and its role in transplantation, however, are only beginning to be appreciated and are the focus of the present review. RECENT FINDINGS Exhausted T cells exhibit a distinct molecular profile reflecting combinatorial mechanisms involving the interaction of multiple transcription factors important in control of cell metabolism, acquisition of effector function and memory capacity. Change of microenvironmental cues and limiting leukocyte recruitment can modulate T-cell exhaustion. Impaired leukocyte recruitment induces T-cell exhaustion and prevents allograft rejection. SUMMARY Preventing or reversing T-cell exhaustion may lead to prevention of transplant tolerance or triggering of rejection; therefore, caution should be exercised in the use of agents blocking inhibitory receptors for the treatment of chronic viral infections or tumors in transplant recipients. Further definition of the role of T-cell exhaustion in clinical transplantation and an understanding of the mechanisms of induction of T-cell exhaustion are needed to develop strategies for preventing allograft rejection and induction of tolerance.
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Shepard MT, Bonney EA. PD-1 regulates T cell proliferation in a tissue and subset-specific manner during normal mouse pregnancy. Immunol Invest 2013; 42:385-408. [PMID: 23782245 DOI: 10.3109/08820139.2013.782317] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The regulation of T cell homeostasis during pregnancy has important implications for maternal tolerance and immunity. Evidence suggests that Programmed Death-1 (PD-1) participates in regulation of T cell homeostasis and peripheral tolerance. To examine the contribution of PD-1 signaling on T cell homeostasis during normal mouse pregnancy, we examined T cell number or proportion, PD-1 expression, proliferation, and apoptosis by flow cytometry, BrdU incorporation, and TUNEL assay in pregnant mice given anti-PD-1 blocking antibody or control on days 10, 12, and 14 of gestation. We observed tissue, treatment, and T cell-specific differences in PD-1 expression. Both pregnancy and PD-1 blockade increased T cell proliferation in the spleen, yet this effect was limited to CD4 T cells in the uterine- draining nodes. In the uterus, PD-1 blockade markedly altered the composition of the T cell pool. These studies support the idea that pregnancy is a state of dynamic T cell homeostasis and suggest that this state is partially supported by PD-1 signaling.
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Affiliation(s)
- Michelle T Shepard
- University of Vermont College of Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, Burlington, VT 05405, USA
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