• anti-inflammation
• arginylglycylaspartic acid
• regulatory macrophage
• vitamin D3
• xenotransplantation

• NRF-2022R1F1A1076227 National Research Foundation of Korea
• No. 22-CM-EC-18 Defense Acquisition Program Administration and Ministry of Trade, Industry and Energy of Korean government

• Fetal tolerance
• Hematopoietic stem cells
• In-utero transplantation
• Maternal microchimerism

• NMRC/CSA INV/0012/2016 National Medical Research Council

• Animals
• Humans
• Immune Tolerance
• Immunosuppression Therapy
• Mesenchymal Stem Cells
• Organ Transplantation/adverse effects
• Transplantation Tolerance

• R01 AI118777 NIAID NIH HHS
• U01 AI136779 NIAID NIH HHS
• U19 AI131453 NIAID NIH HHS

• cell therapy
• clinical trials
• regulatory macrophages
• regulatory myeloid cells
• safety
• tolerogenic dendritic cells

• Animals
• Arthritis, Rheumatoid/immunology
• Arthritis, Rheumatoid/therapy
• Cell- and Tissue-Based Therapy
• Cholecalciferol/pharmacology
• Dendritic Cells/immunology
• Dendritic Cells/transplantation
• Diabetes Mellitus, Type 1/immunology
• Diabetes Mellitus, Type 1/therapy
• Humans
• Immune Tolerance
• Interleukin-10/pharmacology
• Macrophages/immunology
• Macrophages/transplantation
• Transforming Growth Factor beta/pharmacology

• H2020-MSCA-ITN-2019 860003 European Commission

Dendritic cells (DCs) are unique immune cells that can link innate and adaptive immune responses and Immunometabolism greatly impacts their phenotype. Rapamycin is a macrolide compound that has immunosuppressant functions and is used to prevent graft loss in kidney transplantation. The current study evaluated the therapeutic potential of ex-vivo rapamycin treated DCs to protect kidneys in a mouse model of acute kidney injury (AKI). For the rapamycin single (S) treatment (Rapa-S-DC), Veh-DCs were treated with rapamycin (10 ng/mL) for 1 h before LPS. In contrast, rapamycin multiple (M) treatment (Rapa-M-DC) were exposed to 3 treatments over 7 days. Only multiple ex-vivo rapamycin treatments of DCs induced a persistent reprogramming of mitochondrial metabolism. These DCs had 18-fold more mitochondria, had almost 4-fold higher oxygen consumption rates, and produced more ATP compared to Veh-DCs (Veh treated control DCs). Pathway analysis showed IL10 signaling as a major contributing pathway to the altered immunophenotype after Rapamycin treatment compared to vehicle with significantly lower cytokines Tnfa, Il1b, and Il6, while regulators of mitochondrial content Pgc1a, Tfam, and Ho1 remained elevated. Critically, adoptive transfer of rapamycin-treated DCs to WT recipients 24 h before bilateral kidney ischemia significantly protected the kidneys from injury with a significant 3-fold improvement in kidney function. Last, the infusion of DCs containing higher mitochondria numbers (treated ex-vivo with healthy isolated mitochondria (10 µg/mL) one day before) also partially protected the kidneys from IRI. These studies demonstrate that pre-emptive infusion of ex-vivo reprogrammed DCs that have higher mitochondria content has therapeutic capacity to induce an anti-inflammatory regulatory phenotype to protect kidneys from injury.

• acute kidney injury
• dendritic cell
• ischemic reperfusion injury
• mitochondria
• rapamycin

• IDO
• Immunosuppressive drugs
• Tolerance

Over the past century, solid organ transplantation has been improved both at a surgical and postoperative level. However, despite the improvement in efficiency, safety, and survival, we are still far from obtaining full acceptance of all kinds of allograft in the absence of concomitant treatments. Today, transplanted patients are treated with immunosuppressive drugs (IS) to minimize immunological response in order to prevent graft rejection. Nevertheless, the lack of specificity of IS leads to an increase in the risk of cancer and infections. At this point, cell therapies have been shown as a novel promising resource to minimize the use of IS in transplantation. The main strength of cell therapy is the opportunity to generate allograft-specific tolerance, promoting in this way long-term allograft survival. Among several other regulatory cell types, tolerogenic monocyte-derived dendritic cells (Tol-MoDCs) appear to be an interesting candidate for cell therapy due to their ability to perform specific antigen presentation and to polarize immune response to immunotolerance. In this review, we describe the characteristics and the mechanisms of action of both human Tol-MoDCs and rodent tolerogenic bone marrow-derived DCs (Tol-BMDCs). Furthermore, studies performed in transplantation models in rodents and non-human primates corroborate the potential of Tol-BMDCs for immunoregulation. In consequence, Tol-MoDCs have been recently evaluated in sundry clinical trials in autoimmune diseases and shown to be safe. In addition to autoimmune diseases clinical trials, Tol-MoDC is currently used in the first phase I/II clinical trials in transplantation. Translation of Tol-MoDCs to clinical application in transplantation will also be discussed in this review.

• autologous tolerogenic dendritic cells
• cell therapy
• clinical trial
• mechanisms
• safety
• transplantation

The human regulatory macrophage (Mreg) has emerged as a promising cell type for use as a cell-based adjunct immunosuppressive therapy in solid organ transplant recipients. In this brief report, dehydrogenase/reductase 9 (DHRS9) is identified as a robust marker of human Mregs.

The cognate antigen of a mouse monoclonal antibody raised against human Mregs was identified as DHRS9 by immunoprecipitation and MALDI-MS sequencing. Expression of DHRS9 within a panel of monocyte-derived macrophages was investigated by quantitative PCR, immunoblotting and flow cytometry.

DHRS9 expression discriminated human Mregs from a panel of in vitro derived macrophages in other polarisation states. Likewise, DHRS9 expression distinguished Mregs from a variety of human monocyte-derived tolerogenic antigen-presenting cells in current development as cell-based immunotherapies, including Tol-DC, Rapa-DC, DC-10, and PGE₂-induced myeloid-derived suppressor cells. A subpopulation of DHRS9-expressing human splenic macrophages was identified by immunohistochemistry. Expression of DHRS9 was acquired gradually during in vitro development of human Mregs from CD14⁺ monocytes and was further enhanced by IFN-γ treatment on day 6 of culture. Stimulating Mregs with 100 ng/mL lipopolysaccharide for 24 hours did not extinguish DHRS9 expression. Dhrs9 was not an informative marker of mouse Mregs.

DHRS9 is a specific and stable marker of human Mregs.

A brief definitive report that dehydrogenase/reductase 9 (DHRS9) is a robust marker of human, but not mouse, Mregs.

• autoimmunity
• dendritic cells
• systemic lupus erythematosus
• tolerance/suppression/anergy

• Mesenchymal stem cells (MSCs)
• Regulatory T cell (Treg)
• miR-10a
• miR-126a

• Mreg
• cell-based therapy
• minimum information about tolerogenic antigen-presenting cells
• monocyte
• regulatory macrophage
• solid organ transplantation
• suppressor macrophage
• tolerogenic antigen presenting cell (APC)

• basic (laboratory) research/science
• cellular biology
• clinical research/practice
• immune regulation
• immunosuppression/immune modulation
• metabolism/metabolite
• tolerance

Objective. To dissect the efficacy of Tol-DC therapy with or without IS in multiple animal models of transplantation. Methods and Results. PubMed, Medline, Embase, and the Cochrane Library were searched for reviews published up to April 2015. Six systematic reviews and a total of 61 articles were finally included. Data were grouped by organ transplantation models and applied to meta-analysis. Our meta-analysis shows that Tol-DC therapy successfully prolonged allograft survival to varying extents in all except the islet transplantation models and with IS drugs further prolonged the survival of heart, skin, and islet allografts in mice, but not of heart allografts in rats. Compared with IS drugs alone, Tol-DC therapy with IS extended islet allograft survival in rats but failed to influence the survival of skin, small intestine, and heart allografts in rats or of heart and skin allografts in mice. Conclusion. Tol-DC therapy significantly prolonged multiple allograft survival and further prolonged survival with IS. However, standardized protocols for modification of Tol-DC should be established before its application in clinic.

• Dendritic cells
• Immunomodulation
• Mesenchymal stem cells
• Toll like receptors

Corneal transplantation is the most common surgical procedure amongst solid organ transplants with a high survival rate of 86% at 1-year post-grafting. This high success rate has been attributed to the immune privilege of the eye. However, mechanisms originally thought to promote immune privilege, such as the lack of antigen presenting cells and vessels in the cornea, are challenged by recent studies. Nevertheless, the immunological and physiological features of the cornea promoting a relatively weak alloimmune response is likely responsible for the high survival rate in “low-risk” settings. Furthermore, although corneal graft survival in “low-risk” recipients is favourable, the prognosis in “high-risk” recipients for corneal graft is poor. In “high-risk” grafts, the process of indirect allorecognition is accelerated by the enhanced innate and adaptive immune responses due to pre-existing inflammation and neovascularization of the host bed. This leads to the irreversible rejection of the allograft and ultimately graft failure. Many therapeutic measures are being tested in pre-clinical and clinical studies to counter the immunological challenge of “high-risk” recipients. Despite the prevailing dogma, recent data suggest that tissue matching together with use of systemic immunosuppression may increase the likelihood of graft acceptance in “high-risk” recipients. However, immunosuppressive drugs are accompanied with intolerance/side effects and toxicity, and therefore, novel cell-based therapies are in development which target host immune cells and restore immune homeostasis without significant side effect of treatment. In addition, developments in regenerative medicine may be able to solve both important short comings of allotransplantation: (1) graft rejection and ultimate graft failure; and (2) the lack of suitable donor corneas. The advances in technology and research indicate that wider therapeutic choices for patients may be available to address the worldwide problem of corneal blindness in both “low-risk” and “high-risk” hosts.

• “High-risk” grafts
• Graft rejection
• Systemic immunosuppression
• Cell-based immunomodulation
• Keratoprosthesis
• Collagen-based hydrogels

The antigen-presenting dendritic cells (DCs) are key to the immunological response, with different functions ascribed ranging from cellular immune activation to induction of tolerance. Such immunological responses are involved in the pathophysiological mechanisms of cardiovascular diseases, with DCs shown to play a role in atherosclerosis, hypertension, and heart failure and most notably following heart transplantation. A better understanding of the interplay between the immune system and cardiovascular diseases will therefore be critical for developing novel therapeutic treatments as well as innovative monitoring tools for disease progression. As such, the present review will provide an overview of DCs involvement in the pathophysiology of cardiovascular diseases and how targeting these cells may have beneficial effects for the prognosis of patients.

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that bridge innate and adaptive immune responses, thereby leading to immune activation. DCs have been known to recognize pathogen-associated molecular patterns such as lipopolysaccharides (LPS) and nucleic acids via their pattern recognition receptors, which trigger signaling of their maturation and effector functions. Furthermore, DCs take up and process antigens as a form of peptide loaded on the major histocompatibility complex (MHC) and present them to T cells, which are responsible for the adaptive immune response. Conversely, DCs can also play a role in inducing immune suppression under specific circumstances. From this perspective, the role of DCs is related to tolerance rather than immunity. Immunologists refer to these special DCs as tolerogenic DCs (tolDCs). However, the definition of tolDCs is controversial, and there is limited information on their development and characteristics. In this review, we discuss the current concept of tolDCs, cutting-edge methods for generating tolDCs in vitro, and future applications of tolDCs, including clinical use.

• Clinical use
• In vitro generation
• Tolerogenic dendritic cell

Dendritic cells (DC) are rare, professional antigen-presenting cells with ability to induce or regulate alloimmune responses. Regulatory DC (DCreg) with potential to down-modulate acute and chronic inflammatory conditions that occur in organ transplantation can be generated in vitro under a variety of conditions. Here, we provide a rationale for evaluation of DCreg therapy in clinical organ transplantation with the goal of promoting sustained, donor-specific hyporesponsiveness, while lowering the incidence and severity of rejection and reducing patients’ dependence on anti-rejection drugs. Generation of donor- or recipient-derived DCreg that suppress T cell responses and prolong transplant survival in rodents or non-human primates has been well-described. Recently, good manufacturing practice (GMP)-grade DCreg have been produced at our Institution for prospective use in human organ transplantation. We briefly review experience of regulatory immune therapy in organ transplantation and describe our experience generating and characterizing human monocyte-derived DCreg. We propose a phase I/II safety study in which the influence of donor-derived DCreg combined with conventional immunosuppression on subclinical and clinical rejection and host alloimmune responses will be examined in detail.

• dendritic cells
• immune regulation
• renal transplantation

Dendritic cells (DCs), the most important professional antigen-presenting cells (APC), play crucial role in both immunity and tolerance. It is well known that DCs are able to mount immune responses against foreign antigens and simultaneously tolerate self-antigens. Since DCs can be modulated depending on the surrounding microenvironment, they can act as a bridge between innate and adaptive immunity. However, the mechanisms that support this dual role are not entirely clear. Recent studies have shown that DCs can be manipulated ex vivo in order to trigger their tolerogenic profile, what can be a tool to be used in clinical trials aiming the treatment of various diseases and the prevention of transplant rejection. In this sense, the blockage of costimulatory molecules on DC, in the attempt of inhibiting the second signal in the immunological synapse, can be considered as one of the main strategies under development. This review brings an update on current therapies using tolerogenic dendritic cells modulated with costimulatory blockers with the aim of reducing transplant rejection. However, although there are current clinical trials using tolerogenic DC to treat allograft rejection, the actual challenge is to modulate these cells in order to maintain a permanent tolerogenic profile.

• immunology
• immunology and pathology
• immunosuppression
• kidney disease
• macrophages

• Animals
• Dendritic Cells/immunology
• Dendritic Cells/physiology
• Humans
• Immune Tolerance
• Immunotherapy
• Kidney/cytology
• Kidney/immunology
• Kidney Diseases/immunology
• Kidney Transplantation
• Macrophages/immunology
• Macrophages/physiology
• Phenotype
• Receptors, Pattern Recognition
• Urinary Tract Infections/immunology

• CD11b+
• LPS
• corneal transplantation

• Antigen
• Dendritic
• Diabetes
• Immunotherapy
• Microspheres
• Tolerogenic

• Animals
• B7-1 Antigen/genetics
• B7-2 Antigen/genetics
• Blood Glucose/drug effects
• CD11c Antigen/metabolism
• CD40 Antigens/genetics
• Cell Movement/drug effects
• Cell Proliferation/drug effects
• Cells, Cultured
• Dendritic Cells/immunology
• Diabetes Mellitus, Experimental/therapy
• Diabetes Mellitus, Type 1/therapy
• Female
• Forkhead Transcription Factors/analysis
• Gene Knockdown Techniques
• Hyperglycemia/therapy
• Leukocyte Common Antigens/metabolism
• Lymph Nodes/cytology
• Lymph Nodes/immunology
• Lymphocyte Activation/immunology
• Macaca fascicularis
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C3H
• Mice, Inbred NOD
• Mice, Transgenic
• Microspheres
• Oligonucleotides, Antisense/genetics
• Pancreas/immunology
• Receptors, Antigen, T-Cell/genetics
• T-Lymphocytes, Regulatory/cytology
• Vaccines/administration & dosage
• Vaccines/immunology

• R15 AI081218 NIAID NIH HHS
• AI81218 NIAID NIH HHS
• DK063499 NIDDK NIH HHS

• Dendritic cells
• Experimental autoimmune encephalomyelitis
• Regulatory T cells
• Tolerance
• Vitamin D3

• 5-ALA
• allograft
• cardiac transplantation
• foxp3
• regulatory T cell
• tolerance

Systemic autoimmune diseases can damage nearly every tissue or cell type of the body. Although a great deal of progress has been made in understanding the pathogenesis of autoimmune diseases, current therapies have not been improved, remain unspecific and are associated with significant side effects. Because dendritic cells (DCs) play a major role in promoting immune tolerance against self-antigens (self-Ags), current efforts are focusing at generating new therapies based on the transfer of tolerogenic DCs (tolDCs) during autoimmunity. However, the feasibility of this approach during systemic autoimmunity has yet to be evaluated. TolDCs may ameliorate autoimmunity mainly by restoring T cell tolerance and, thus, indirectly modulating autoantibody development. In vitro induction of tolDCs loaded with immunodominant self-Ags and subsequent cell transfer to patients would be a specific new therapy that will avoid systemic immunosuppression. Herein, we review recent approaches evaluating the potential of tolDCs for the treatment of systemic autoimmune disorders.

• Anti-Inflammatory Agents/pharmacology
• Anti-Inflammatory Agents/therapeutic use
• Autoimmune Diseases/drug therapy
• Autoimmune Diseases/metabolism
• Autoimmune Diseases/pathology
• B-Lymphocytes/immunology
• Cholecalciferol/therapeutic use
• Dendritic Cells/drug effects
• Dendritic Cells/immunology
• Dendritic Cells/metabolism
• Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use
• Humans
• Immune Tolerance
• Nitriles/therapeutic use
• Sulfones/therapeutic use
• T-Lymphocytes/immunology

A new cell-based medicinal product containing human regulatory macrophages, known as Mreg_UKR, has been developed and conforms to expectations of a therapeutic drug. Here, Mreg_UKR was subjected to pharmacokinetic, safety pharmacology, and toxicological testing, which identified no adverse reactions. These results would normally be interpreted as evidence of the probable clinical safety of Mreg_UKR; however, we contend that, owing to their uncertain biological relevance, our data do not fully support this conclusion. This leads us to question whether there is adequate scientific justification for preclinical safety testing of similar novel cell-based medicinal products using animal models. In earlier work, two patients were treated with regulatory macrophages prior to kidney transplantation. In our opinion, the absence of acute or chronic adverse effects in these cases is the most convincing available evidence of the likely safety of Mreg_UKR in future recipients. On this basis, we consider that safety information from previous clinical investigations of related cell products should carry greater weight than preclinical data when evaluating the safety profile of novel cell-based medicinal products. By extension, we argue that omitting extensive preclinical safety studies before conducting small-scale exploratory clinical investigations of novel cell-based medicinal products data may be justifiable in some instances.

• acute cellular rejection
• biomarker
• dendritic cells
• flow cytometry
• heart transplantation

• immune regulation
• myeloid cells
• transplantation

• Adoptive Transfer
• Animals
• Antigens/metabolism
• Cell Culture Techniques
• Cell Movement
• Cell Survival
• Cell Transplantation/methods
• Dendritic Cells/cytology
• Dendritic Cells/immunology
• Humans
• Immune Tolerance
• Immunosuppression Therapy/methods
• Immunosuppressive Agents/therapeutic use
• Immunotherapy/methods
• Inflammation
• Leukocytes, Mononuclear/immunology
• Leukocytes, Mononuclear/transplantation
• Macrophages/cytology
• Macrophages/immunology
• Mice
• Myeloid Cells/immunology
• Myeloid Cells/transplantation
• Rats
• Transplantation Tolerance/immunology

• P01 AI081678 NIAID NIH HHS
• T32 AI074490 NIAID NIH HHS
• R00 HL097155 NHLBI NIH HHS
• T32AI07449 NIAID NIH HHS
• P01AI81678 NIAID NIH HHS
• R00HL097155 NHLBI NIH HHS
• K99 HL097155 NHLBI NIH HHS
• U01AI51698 NIAID NIH HHS
• R01AI67541 NIAID NIH HHS
• R01 AI067541 NIAID NIH HHS
• U01 AI051698 NIAID NIH HHS

Type 1 diabetes (T1D) is a T cell mediated autoimmune disease characterized by immune mediated destruction of the insulin-producing β cells in the islets of Langerhans. Dendritic cells (DC) have been implicated in the pathogenesis of T1D and are also used as immunotherapeutic agents. Plasmacytoid (p)DC have been shown to have both protective and pathogenic effects and a newly described merocytic DC population has been shown to break tolerance in the mouse model of T1D, the non-obese diabetic (NOD) mouse. We have used DC populations to prevent the onset of T1D in NOD mice and clinical trials of DC therapy in T1D diabetes have been initiated. In this review we will critically examine the recent published literature on the role of DC subsets in the induction and regulation of the autoimmune response in T1D.

• T regulatory cells
• autoimmunity
• dendritic cells
• tolerance
• type 1 diabetes

Immune monitoring by flow cytometry is a fast and highly informative way of studying the effects of novel therapeutics aimed at reducing transplant rejection or treating autoimmune diseases. The ONE Study consortium has recently initiated a series of clinical trials aimed at using different cell therapies to promote tolerance to renal allografts. To compare the effectiveness of different cell therapies, the consortium developed a robust immune monitoring strategy, including procedures for whole blood (WB) leukocyte subset profiling by flow cytometry.

Six leukocyte profiling panels computing 7- to 9-surface marker antigens for monitoring the major leukocyte subsets as well as characteristics of T cell, B cell, and dendritic cell (DC) subsets were designed. The precision and variability of these panels were estimated. The assay was standardized within eight international laboratories using Flow-Set Pro beads for mean fluorescence intensity target definition and the flow cytometer setup procedure. Standardization was demonstrated by performing inter-site comparisons.

Optimized methods for sample collection, storage, preparation, and analysis were established, including protocols for gating target subsets. WB specimen age testing demonstrated that staining must be performed within 4 hours of sample collection to keep variability low, meaning less than or equal to 10% for the majority of defined leukocyte subsets. Inter-site comparisons between all participating centers testing shipped normal WB revealed good precision, with a variability of 0.05% to 30% between sites. Intra-assay analyses revealed a variability of 0.05% to 20% for the majority of subpopulations. This was dependent on the frequency of the particular subset, with smaller subsets showing higher variability. The intra-assay variability performance defined limits of quantitation (LoQ) for subsets, which will be the basis for assessing statistically significant differences achieved by the different cell therapies.

Local performance and central analysis of the ONE Study flow cytometry panel yields acceptable variability in a standardized assay at multiple international sites. These panels and procedures with WB allow unmanipulated analysis of changes in absolute cell numbers of leukocyte subsets in single- or multicenter clinical trials. Accordingly, we propose the ONE Study panel may be adopted as a standardized method for monitoring patients in clinical trials enrolling transplant patients, particularly trials of novel tolerance promoting therapies, to facilitate fair and meaningful comparisons between trials.

• DNA methylation
• histone modifications
• rejection
• tolerance

Several types of myeloid suppressor cell are currently being developed as cell-based immunosuppressive agents. Despite detailed knowledge about the molecular and cellular functions of these cell types, expert opinions differ on how to best implement such therapies in solid organ transplantation. Efforts in our laboratory to develop a cell-based medicinal product for promoting tolerance in renal transplant patients have focused on a type of suppressor macrophage, which we call the regulatory macrophage (M reg). Our favoured clinical strategy is to administer donor-derived M regs to recipients one week prior to transplantation. In contrast, many groups working with tolerogenic dendritic cells (DCs) advocate post-transplant administration of recipient-derived cells. A third alternative, using myeloid-derived suppressor cells, presumably demands that cells are given around the time of transplantation, so that they can infiltrate the graft to create a suppressive environment. On present evidence, it is not possible to say which cell type and treatment strategy might be clinically superior. This review seeks to position our basic scientific and early-stage clinical studies of human regulatory macrophages within the broader context of myeloid suppressor cell therapy in transplantation.