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Background: Tacrolimus is the calcineurin inhibitor of choice for preventing acute rejection episodes in kidney transplant patients. However, tacrolimus has a narrow therapeutic range that requires regular monitoring of blood concentrations to minimize toxicity. A new once-daily tacrolimus formulation, LCP-tacrolimus (LCPT), has been developed, which uses MeltDose™ drug-delivery technology to control drug release and enhance overall bioavailability. Our study compared dosing of LCPT with current standard-of-care tacrolimus [immediate-release tacrolimus (IR-Tac) or prolonged-release tacrolimus (PR-Tac)] during the 6 months following de novo kidney transplantation. Comparisons of graft function, clinical outcomes, safety, and tolerability for LCPT versus IR-Tac/PR-Tac were also performed. Methods: Standard immunological risk patients with end-stage renal disease who had received a de novo kidney transplant were randomized (1:1) to LCPT (N = 200) or IR-Tac/PR-Tac (N = 201). Results: Least squares (LS) mean tacrolimus total daily dose from Week 3 to Month 6 was significantly lower for LCPT than for IR-Tac/PR-Tac. Although LS mean tacrolimus trough levels were significantly higher for LCPT than IR-Tac/PR-Tac, tacrolimus trough levels remained within the standard reference range for most patients. There were no differences between the groups in treatment failure measures or safety profile. Conclusion: LCPT can achieve similar clinical outcomes to other tacrolimus formulations, with a lower daily dose. Clinical Trial Registration: https://clinicaltrials.gov/, identifier NCT02432833., Competing Interests: GP, DS, SG, CP, and GN are all employees of Chiesi Farmaceutici S.p.A. KB has received honoraria and/or research funding from Alexion, Astellas, Bristol-Myers Squibb, Chiesi, Fresenius, Hansa, Hexal, Merck, Novartis, Otsuka, Pfizer, Roche, Sandoz, Siemens, and Veloxis Pharmaceuticals. UM received participation fees from Chiesi for scientific advisory boards. LR has been an advisor for Hansa and Biotest; has received speaker fees from Astellas, Novartis, Chiesi and Bristol-Myers Squibb; and has received grants from Chugai, Terumo and HemaT. GP, who is now an employee of Chiesi Farmaceutici S.p.A., worked at Dipartimento di Medicina e Chirurgia, UO Nefrologia, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy at the time of the study and received consulting fees from Chiesi for work as a medical research physician for the present study. OW has received research grants for clinical studies, speaker's fees, honoraria, and travel expenses from Amgen, Astellas, Bristol-Myers Squibb, Chiesi, Hexal, Janssen-Cilag, MSD, Novartis, Pfizer, Roche, and Sanofi. DS received consulting fees from Chiesi for work as a clinical study manager for the present study. NK has received speaker fees and participated in advisory boards for Abbvie, Amgen, Astellas, Chiesi, Fresnius Medical Care, Gilead, Merck Sharp and Dohme, Neovii, Novartis, Roche, Sanofi, and Shire. MB has received funds for travel from Astellas and Chiesi. JP has received consulting fees from Chiesi. DK has received honoraria from Chiesi and Astellas. TW has received honoraria from Chiesi and Therakos/Mallinckrodt, and research funding from Astellas, Chiesi, Neovii, Novartis, Sandoz, Sanofi, and Teva. AG-D has received travel grants, speaker fees, and/or advisory board honoraria from Alexion, Chiesi, MSD and Novartis, and has participated in clinical trials sponsored by Alexion, Astellas, Chiesi and Novartis. LW had received research funding from Chiesi. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study (ClinicalTrials.gov, NCT02432833) was funded by Chiesi Farmaceutici SpA. The funder was involved in study design, collection, analysis and interpretation of data. All co-authors have contributed substantially to the analyses and interpretation of the data, and have provided important intellectual input and approval of the final version of the manuscript. Fishawack Inc. has received funding by Chiesi Farmaceutici SpA to provide medical writing support., (Copyright © 2022 Budde, Rostaing, Maggiore, Piotti, Surace, Geraci, Procaccianti, Nicolini, Witzke, Kamar, Albano, Büchler, Pascual, Gutiérrez-Dalmau, Kuypers, Wekerle, Głyda, Carmellini, Tisone, Midtvedt, Wennberg and Grinyó.)

Impaired cytomegalovirus (CMV)-specific cell-mediated immunity (CMV-CMI) is a major cause of CMV reactivation and associated complications in solid-organ transplantation. Reliably assessing CMV-CMI is desirable to individually adjust antiviral and immunosuppressive therapy. This study aimed to evaluate the suitability of T-Track ® CMV, a novel IFN-γ ELISpot assay based on the stimulation of peripheral blood mononuclear cells with pp65 and IE-I CMV proteins, to monitor CMV-CMI following kidney transplantation. A prospective longitudinal multicenter study was conducted in 86 intermediate-risk renal transplant recipients. CMV-CMI, CMV viral load, and clinical complications were monitored over 6 months post-transplantation. Ninety-five percent and 88-92% ELISpot assays were positive pre- and post-transplantation, respectively. CMV-specific response was reduced following immunosuppressive treatment and increased in patients with graft rejection, indicating the ability of the ELISpot assay to monitor patients' immunosuppressive state. Interestingly, median pp65-specific response was ninefold higher in patients with self-clearing viral load compared to antivirally treated patients prior to first viral load detection (P < 0.001), suggesting that reactivity to pp65 represents a potential immunocompetence marker. Altogether, T-Track ® CMV is a highly sensitive IFN-γ ELISpot assay, suitable for the immunomonitoring of CMV-seropositive renal transplant recipients, and with a potential use for the risk assessment of CMV-related clinical complications (ClinicalTrials.gov Identifier: NCT02083042)., (© 2017 The Authors. Transplant International published by John Wiley & Sons Ltd on behalf of Steunstichting ESOT.)

While belatacept has shown favorable short- and midterm results in kidney transplant recipients, only projections exist regarding its potential impact on long-term outcome. Therefore, we performed a retrospective case-match analysis of the 14 belatacept patients originally enrolled in the phase II multicenter trial at our center. Fifty six cyclosporine (CyA)-treated patients were matched according to age at transplantation, first/retransplant, and donor type. Ten years after kidney transplantation, kidney function remained superior in belatacept-treated patients compared with the CyA control group. Moreover, none of the belatacept-treated patients had donor-specific antibodies ≥10 years post-transplantation compared with 38.5% of tested CyA-treated subject (0/10 vs. 5/13; P = 0.045). Notably, however, patient and graft survival was virtually identical in both groups (71.4% vs. 71.3%; P = 0.976). In the present single-center study population, patients treated with belatacept demonstrated a patient and graft survival at 10 years post-transplant which was comparable to that of similarly selected CNI-treated patients. Larger studies with sufficient statistical power are necessary to definitively determine long-term graft survival with belatacept., (© 2015 Steunstichting ESOT.)

While costimulation blockade-based mixed chimerism protocols work well for inducing tolerance in rodents, translation to preclinical large animal/nonhuman primate models has been less successful. One recognized cause for these difficulties is the high frequency of alloreactive memory T cells (Tmem) found in the (pre)clinical setting as opposed to laboratory mice. In the present study, we therefore developed a murine bone marrow transplantation (BMT) model employing recipients harboring polyclonal donor-reactive Tmem without concomitant humoral sensitization. This model was then used to identify strategies to overcome this additional immune barrier. We found that B6 recipients that were enriched with 3 × 10(7) T cells isolated from B6 mice that had been previously grafted with Balb/c skin, rejected Balb/c BM despite costimulation blockade with anti-CD40L and CTLA4Ig (while recipients not enriched developed chimerism). Adjunctive short-term treatment of sensitized BMT recipients with rapamycin or anti-LFA-1 mAb was demonstrated to be effective in controlling Tmem in this model, leading to long-term mixed chimerism and donor-specific tolerance. Thus, rapamycin and anti-LFA-1 mAb are effective in overcoming the potent barrier that donor-reactive Tmem pose to the induction of mixed chimerism and tolerance despite costimulation blockade., (© 2012 The Authors Transplant International © 2012 European Society for Organ Transplantation. Published by Blackwell Publishing Ltd.)

Gradually improved immunosuppression has contributed significantly to the progress achieved in transplantation medicine so far. Nevertheless, current drug regimens are associated with late graft loss--in particular as a result of immunologic damage or drug toxicity--and substantial morbidity. Recently, the costimulation blocker belatacept (marketed under the name Nulojix®) has been approved for immunosuppression in renal transplantation. Belatacept (a mutated version of CTLA4Ig) is a fusion protein rationally designed to block CD28, a critical activating receptor on T cells, by binding and saturating its ligands B7-1 and B7-2. In phase II and III trials, belatacept was compared with cyclosporine (in combination with basiliximab, MMF, and steroids). Advantages observed with belatacept include superior graft function, preservation of renal structure and improved cardiovascular risk profile. Concerns associated with belatacept are a higher frequency of cellular rejection episodes and more post-transplant lymphoproliferative disorder (PTLD) cases especially in EBV seronegative patients, who should be excluded from belatacept-based regimens. Thus, after almost three decades of calcineurin inhibitors as mainstay of immunosuppression, belatacept offers a potential alternative. In this article, we will provide an overview of belatacept's preclinical development and will discuss the available evidence from clinical trials., (© 2011 The Authors. Transplant International © 2011 European Society for Organ Transplantation.)

The increased use of older and/or marginal donor organs in liver transplantation over the last decade calls for strategies to minimize ischaemic reperfusion (I/R) injury to prevent early graft failure. Tacrolimus, a very potent and effective calcineurin inhibitor, was selected because of its ability to ameliorate I/R injury. A randomized, blinded, controlled single-centre trial of 26 liver transplant recipients was performed between February 2008 and December 2009. Donor organs were randomized to be perfused intraportally during liver transplantation with 1.5 l 5% albumin infusion containing either 20 ng/ml tacrolimus or placebo. The primary end point was liver function as assessed by aspartate transaminase (AST) or alanine transaminase (ALT) levels 6 days after transplantation. Treatment effectiveness was tested by transcriptome-wide analysis of biopsies. There was no difference in the primary end point, i.e. AST (IU/l) and ALT (IU/l) at day 6 after transplantation between groups. Furthermore, choleastatic parameters as well as parameters of liver synthesis were not different between groups. However, tacrolimus treatment suppressed inflammation and immune response in the transplanted liver on a genome-wide basis. Intrahepatic administration of tacrolimus did not result in a reduction of AST and ALT within the first week after transplantation., (© 2011 The Authors. Transplant International © 2011 European Society for Organ Transplantation.)

Distinct lymphocyte populations have been identified that either promote or impede the establishment of chimerism and tolerance through allogeneic bone marrow transplantation (BMT). Natural killer T (NKT) cells have pleiotropic regulatory properties capable of either augmenting or downmodulating various immune responses. We investigated in this study whether NKT cells affect outcome in mixed chimerism models employing fully mismatched nonmyeloablative BMT with costimulation blockade (CB). The absence of NKT cells had no detectable effect on chimerism or skin graft tolerance after conditioning with 3Gy total body irradiation (TBI), and a limited positive effect with 1Gy TBI. Stimulation of NKT cells with alpha-galactosylceramide (alpha-gal) at the time of BMT prevented chimerism and tolerance. Activation of recipient (as opposed to donor) NKT cells was necessary and sufficient for the alpha-gal effect. The detrimental effect of NKT activation was also observed in the absence of T cells after conditioning with in vivo T-cell depletion (TCD). NKT cells triggered rejection of BM via NK cells as chimerism and tolerance were not abrogated when NKT cells were stimulated in the absence of both NK cells and T cells. Thus, activation of NKT cells at the time of BMT overcomes the effects of CB, inhibiting the establishment of chimerism and tolerance., (© 2010 The Authors. Journal compilation © 2010 European Society for Organ Transplantation.)

Tolerance induction by mixed chimerism and costimulation blockade is a promising approach to avoid immunosuppression, but the molecular basis of tolerant T lymphocytes remains elusive. We investigated the genome-wide gene expression profile of murine T lymphocytes after tolerance induction by allogeneic bone marrow transplantation (BMT) and costimulatory blockade using the anti-CD40L antibody MR1. Molecular functions, biological processes, cellular locations, and coregulation of identified genes were determined. A total of 113 unique genes exhibited a significant differential expression between the lymphocytes of MR1-treated Tolerance (TOL) and untreated recipients Control (CTRL). The majority of genes upregulated in the TOL group are involved in several signal transduction cascades such as members of the MAPKKK cascade (IL6, Tob2, Stk39, and Dusp24). Other genes involved in lymphocyte differentiation and highly expressed in the TOL group are lymphotactin, the estrogen receptors (ERs) and the suppressor of cytokine signaling 7. Common transcription factors such as ER 1 alpha, GATA-binding protein 1, insulin promoter factor 1, and paired-related homeobox 2 could be identified in the promoter regions of upregulated genes in the TOL group. These data suggest that T lymphoctes of tolerant mice exhibit a distinct molecular expression profile, which needs to be evaluated in other experimental tolerance models to determine whether it is a universal signature of tolerance.

Current immunosuppressive therapy in clinical organ transplantation is based on drugs that suppress various functions of immunocompetent cells but still affect cells and organ compartments other than the immune system. Hence, these drugs have considerable side effects which lead to increased morbidity and reduced life-quality of transplant recipients. A major step forward in the rationale design of clinical immunosuppression resides in the elucidation of molecular targets that play a critical role specifically within the immune system. Recently, Janus kinase 3 (JAK3) has been identified as such a molecule. Genetic absence or ablation of this tyrosine kinase is associated with defective T-cell immunity that results in severe combined immunodeficiency (SCID) without apparent changes in other organ systems. Furthermore, pharmacological inhibition has significantly prolonged allograft survival in several experimental models of organ transplantation. The present review provides an overview of the emerging role of JAK3 in the immune system and the development of JAK3-inhibiting drugs. The potential clinical application of JAK3 inhibitors in organ transplantations is discussed in the light of a recent series of successful kidney transplantations in non-human primates immunosuppressed solely with a novel JAK3 inhibitor.

In a recently developed murine model for the induction of mixed chimerism and tolerance, hosts are treated with T cell depleting monoclonal antibodies (TCD mAbs; days -5, -1 and +7), thymic irradiation (TI) (7 Gy), and a high dose of fully allogeneic bone marrow cells (BMC, 200 x 10(6)). To find the minimum amount of each treatment required for success with this approach, we treated groups with (1) a lower dose of TI (3.5 Gy), (2) fewer BMC (100 x 10(6)), (3) no TI, (4) no TI plus additional TCD mAbs on day +14, or (5) fewer injections of TCD mAbs (day -5 only). Chimerism was followed by flow cytometry (FCM), and tolerance was assessed by skin grafting. Without TI, no long-term chimerism or tolerance could be induced, even when an additional dose of TCD mAbs was administered on day +14. A reduction in the dose of either BMC or TI led to substantially reduced effectiveness, as demonstrated by lower levels of chimerism and poorer donor skin graft survival. However, the dose of TCD mAbs and hence the duration of recipient T cell depletion could be safely reduced and thus the potential toxicity of the conditioning regimen lowered.

The short-chain fatty acid n-butyrate has recently been shown in vitro to specifically downregulate T cell reactivity to nominal antigen or to alloantigen, which possibly results from inhibition of cell cycle progression in early G1 phase during antigen contact. In the present study, we investigated the effect of cyclosporin A (CyA) on the modulation of alloreactivity in human mixed lymphocyte culture (MLC) by n-butyrate. Whereas in primary culture, CyA additively enhanced inhibition of DNA synthesis by n-butyrate, the effect of this agent on secondary T cell reactivity was clearly antagonized by CyA. Thus, specific downregulation of proliferative responsiveness to restimulation with antigen from the original donor, observed in cultures pretreated with n-butyrate alone, was at least partially prevented by the addition of CyA to the primary culture. Our in vitro finding indicates that specific downregulation of T cell alloreactivity by n-butyrate might depend on a calcium-dependent T cell receptor (TCR)-mediated signal sensitive to the immunosuppressive action of CyA.