vival. Conclusions: The risk for mortality after HTx or LuTx is not increased by ESRD, provided t... more vival. Conclusions: The risk for mortality after HTx or LuTx is not increased by ESRD, provided that patients meet access criteria for the KTx waiting list. KTx improves survival in ESRD after HTx or LuTx. BMI and LVEF may predict outcome in HTx/ LuTx patients on the KTx waiting list.
When dealing with T lymphocyte culture there is currently very less information available about t... more When dealing with T lymphocyte culture there is currently very less information available about the interaction between T-cells and the culture system. In this study we look at the influence of the culture chamber on T-cell proliferation in two main aspects of the culture system, namely: culture chamber material and geometry. The study was carried out using unique polymeric closed cell culture inserts, which were processed via injection moulding from polystyrene (PS), polycarbonate (PC), polyetherurethane (PEU), polystyrene-co-acrylonitrile (PSAN) and polyetherimide (PEI). Furthermore culture chamber geometry was studied using commercially available 24, 12 and 6-well plates prepared from tissue culture plastic (TCP). For T lymphocyte stimulation two methods were used involving either EBV peptide pools or MACS iBead particles depending on the experiment performed. Culture was done with 1645 RPMI medium supplemented with foetal calf serum, penicillin, streptomycin and rhIL-2. We found four materials out of five we tested (PS, PC, PSAN and PEI) exhibited similar fold expansions with minimal influence on proportions of CD4 and CD8, while PEU had a negative influence on T cell growth along with adversely affected CD4/CD8 proportions. Changes in the geometry of TCP had no effect on T cell growth or maturation rather the size of geometry seems to have more influence on proliferation. T-cells appear to prefer smaller geometries during initial stages of culture while towards the end of the culture size becomes less significant to cell proliferation. The parameters tested in this study have significant influences on T-cell growth and are necessary to consider when designing and constructing expansion systems for antigen specific T lymphocytes. This is important when culturing T-cells for immunotherapeutic applications where antigen specificity, T-cell maturation and function should remain unaffected during culture.
Little is known about thymus function in transplant patients. Until recently, the phenotype of T ... more Little is known about thymus function in transplant patients. Until recently, the phenotype of T cells that recently emigrated the thymus was unknown. Now it has been demonstrated that CD4(+) recent thymus emigrants coexpress CD31 and CD45RA. Here, we investigated whether uremia and immunosuppression influence CD31(+) CD45RA(+) Th cells before and after kidney transplantation, respectively. Forty-eight renal transplant patients were included receiving either standard triple/quadruple (n = 35) immunosuppression, OKT-3 induction (n = 7) or FTY-720 (n = 6), respectively. Peripheral CD31(+) CD45RA(+) Th cells were quantified flowcytometrically before and at week 1, 4, 12 and 24 post-transplantation. Thirty-nine healthy adults served as controls. CD31(+) CD45RA(+) Th cells correlated inversely with age in patients and controls and were comparable in patients before transplantation and age-matched controls. Importantly, CD31(+) CD45RA(+) Th cell frequencies remained stable during 6 months post-transplantation. In conclusion, CD31(+) CD45RA(+) Th cells are not significantly altered by uremia before and during 6 months of immunosuppressive therapy after kidney transplantation. Implications for thymus function are discussed.
Investigating the health-economic profiles of biomarker-driven immunosuppresion (BIO-DrIM) follow... more Investigating the health-economic profiles of biomarker-driven immunosuppresion (BIO-DrIM) following solid organ transplantation.
Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in kidney transplant recipients (K... more Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in kidney transplant recipients (KTR), but risk factors remain poorly defined. CD4+ T lymphopenia and mannose-binding lectin (MBL) deficiency are common immunodeficiencies in KTR. Here, we investigated whether CD4+ T lymphopenia and/or MBL deficiency would be risk factors for PCP in KTR. Furthermore, the role of thymic function in CD4+ T lymphopenia and outcome was studied by assessing CD45RA+CD31+CD4+ T cell numbers (RTE, recent thymus emigrants). In 321 de novo KTR serial determinations of peripheral T lymphocyte subsets (n=281, mean 4.2 times between days 0-365) and/or MBL levels (n=112, mean 1.8 times between days 30-180) were performed. 22/321 patients developed a PCP episode on average at day 199 (107-398) post-Tx. Age correlated inversely with RTE, CD4+ and CD8+ T-cell counts until day 180 post-Tx. RTE correlated with CD4+ T-cell counts at all time-points pre- and post-Tx. PCP patients had more CMV infections (p=0.045) within the first 3 months compared to controls. Importantly, PCP patients were older (p=0.008), and had lower RTE (p=0.046) pretransplant, and lower CD4+ T-cell counts pretransplant (p=0.017), at day 60 (p=0.032) and for the average of all post-Tx values (p=0.027) compared to controls. Though treatment with T-cell depleting antibodies was associated with consecutive CD4+ T lymphopenia in the whole cohort, the number of patients who received T-cell depleting antibodies was comparable between PCP and control patients (p=0.754). A multivariate stepwise logistic regression model identified only pretransplant CD4+ T-cell counts (OR 0.011, p=0.010) and acute rejection (OR 4.66, p=0.023) as predictors of PCP. In contrast, MBL levels and incidence of MBL deficiency (<500 ng/ml) at days 30, 90 and 180 post-Tx were not different between PCP patients and controls. In conclusion, PCP risk was associated with higher age and related to both thymic functional impairment and long-lasting CD4+ T-lymphopenia that started already before transplantation. Despite frequent occurrences in KTR, low levels of serum MBL were not associated with increased risk for PCP. CD4+ T-cell counts and function should be addressed in prospective studies for more individualized approaches to PCP prophylaxis.
We compared steady-state pharmacokinetics of mycophenolate mofetil (MMF)-Myfenax Ò (Teva) and Cel... more We compared steady-state pharmacokinetics of mycophenolate mofetil (MMF)-Myfenax Ò (Teva) and CellCept Ò (Roche)-in stable kidney transplant recipients (KTRs). This was an international, multi-centre, randomized, open-label, two-treatment, two-sequence crossover study with a 3-month follow-up. We included KTRs at least 12 months post-transplantation with stable renal graft function for at least 3 months. The maintenance treatment consisted of MMF in combination with tacrolimus with or without steroids. At the end of the two treatment periods, 6-h or 12-h PK studies of mycophenolic acid (MPA) were performed. A total of 43 patients (mean age: 50.7 ± 13.5 years; 19 females, 24 males) were randomized. Estimates of test to reference ratios (90% CIs) were 0.959 (0.899; 1.023) h*lg/ml for AUC (0-tau) and 0.873 (0.787; 0.968) lg/ml for C max. Estimates for AUC (0-6h) were 0.923 (0.865; 0.984) h*lg/ ml and 0.985 (0.877; 1.106) lg/ml for C min. Thus, AUC (0-tau) , AUC (0-6h) , and C min of MPA were within the predefined margins. C max was somewhat outside of these margins in this set of patients. The numbers and types of adverse events were not different between the two treatments. The steady-state pharmacokinetics of MPA as well as adverse events are comparable for Myfenax Ò and CellCept Ò in tacrolimus-treated stable KTRs. (EudraCT-No.: 2009-010562-31; ClinicalTrials.Gov number: NCT00991510)
The success of human induced pluripotent stem cell (hiPSC)-based therapy critically depends on un... more The success of human induced pluripotent stem cell (hiPSC)-based therapy critically depends on understanding and controlling the immunological effects of the hiPSC-derived transplant. While hiPSC-derived cells used for cell therapy are often immature with post-grafting maturation, immunological properties may change, with adverse effects on graft tolerance and control. In the present study, the allogeneic and autologous cellular immunity of hiPSC-derived progenitor and terminally differentiated cells were investigated in vitro. In contrast to allogeneic primary cells, hiPSC-derived early renal progenitors and mature renal epithelial cells are both tolerated not only by autologous but also by allogeneic T cells. These immune-privileged properties result from active immunomodulation and low immune visibility, which decrease during the process of cell maturation. However, autologous and allogeneic natural killer (NK) cell responses are not suppressed by hiPSC-derived renal cells and ef...
Regulatory Tcells (Treg) are essential components of peripheral immune homeostasis. Adoptive Treg... more Regulatory Tcells (Treg) are essential components of peripheral immune homeostasis. Adoptive Treg cell therapy has shown efficacy in a variety of immune-mediated diseases in preclinical studies and is now moving from phase I/IIa to larger phase II studies aiming to demonstrate efficacy. However, hurdles such asin vivostability and efficacy remain to be addressed. Nevertheless, preclinical models have shown that Treg function and specificity can be increased by pharmacological substances or gene modifications, and even that conventional T cells can be converted to Treg potentially providing new sources of Treg and facilitating Treg cell therapy. The exponential growth in genetic engineering techniques and their application to T cells coupled to a large body of knowledge on Treg open numerous opportunities to generate Treg with “superpowers”. This review summarizes the genetic engineering techniques available and their applications for the next-generation of Super-Treg with increased ...
ABSTRACTIntroductionLong-term graft survival rates after renal transplantation are still moderate... more ABSTRACTIntroductionLong-term graft survival rates after renal transplantation are still moderate. We aimed to build an early predictor of an established long-term outcomes marker, the glomerular filtration rate (eGFR) one year post-transplant (eGFR-1y).Materials and MethodsA large cohort of 376 patients was characterized for a multi-level bio-marker panel including gene expression, cytokines, metabolomics and antibody reactivity profiles. Almost one thousand samples from the pre-transplant and early post-transplant period were analysed. Machine learning-based predictors were built employing stacked generalization.ResultsPre-transplant data led to a prediction achieving a Pearson’s correlation coefficient of r=0.39 between measured and predicted eGFR-1y. Two weeks post-transplant, the correlation was improved to r=0.63, and at the third month, to r=0.76. eGFR values were remarkably stable throughout the first year post-transplant and were the best estimators of eGFR-1y already two w...
Background Use of cell-based medicinal products (CBMPs) represents a state-of-the-art approach fo... more Background Use of cell-based medicinal products (CBMPs) represents a state-of-the-art approach for reducing general immunosuppression in organ transplantation. We tested multiple regulatory CBMPs in kidney transplant trials to establish the safety of regulatory CBMPs when combined with reduced immunosuppressive treatment. Methods The ONE Study consisted of seven investigator-led, single-arm trials done internationally at eight hospitals in France, Germany, Italy, the UK, and the USA (60 week follow-up). Included patients were living-donor kidney transplant recipients aged 18 years and older. The reference group trial (RGT) was a standard-of-care group given basiliximab, tapered steroids, mycophenolate mofetil, and tacrolimus. Six non-randomised phase 1/2A cell therapy group (CTG) trials were pooled and analysed, in which patients received one of six CBMPs containing regulatory T cells, dendritic cells, or macrophages; patient selection and immunosuppression mirrored the RGT, except basiliximab induction was substituted with CBMPs and mycophenolate mofetil tapering was allowed. None of the trials were randomised and none of the individuals involved were masked. The primary endpoint was biopsyconfirmed acute rejection (BCAR) within 60 weeks after transplantation; adverse event coding was centralised. The RTG and CTG trials are registered with ClinicalTrials.gov,
Chimeric antigen receptor (CAR) technology and its application to regulatory T cells (Tregs) has ... more Chimeric antigen receptor (CAR) technology and its application to regulatory T cells (Tregs) has been hailed as the next scientific breakthrough in the field of cell and gene therapy. Merging the benefits of CAR technology with Tregs offers a novel and promising therapeutic option for durable reshaping of undesired immune responses following solid organ or hematopoietic stem cell transplantation, as well as in immune-related disorders. However, major challenges remain for developing a standardized, robust, and reliable good manufacturing practice (GMP)-compliant manufacturing process for CAR-Treg cells. We review current progress in the field and recommend ways to improve current CAR-Treg manufacturing processes based on lessons learned from first-generation Treg therapeutics as well as from anticancer CART cell development. The New Era of Cell and Gene Therapy One recent and exciting example of progress in the field of cell and gene therapy has been the ongoing development of chimeric antigen receptor (CAR; see Glossary) technology and its application to regulatory T cells (Tregs) [1-3]. There is a high medical need for more effective and sustainable therapies targeting immune-related diseases as a result of an increase in their prevalence (N10% of chronic diseases) and the high socioeconomic burden associated with managing long-term illness and chronic conditions (e.g., N100 billion €/year in the EU). Adoptive cell transfer (ACT) of Tregs is a promising therapeutic option to reshape immune balance toward tolerance with long-lasting efficacy. First-inhuman (FIH) trials with first-generation thymus Treg cell products have yielded promising data regarding safety and efficacy in immune-related disorders [2,3]. Advances in the development of genetically modified CART cells targeting malignancies will, in all likelihood, also accelerate the clinical translation of CAR-Treg cells [4]. The introduction of costimulatory domains such as cluster of differentiation (CD) molecules CD28 and CD137 has allowed the engineered CART cells to persist and remain active within the body [5]. CART cell therapies have been successfully investigated in a multitude of Phase I and II trials where autologous or allogeneic tumor-specific CART cells were applied. By the end of 2017, these efforts led to marketing approval of two CART cell therapy products, tisagenlecleucel (Kymriah®, Novartis) and axicabtagene ciloleucel (Yescarta®, Kite Pharma/Gilead) in the USA and subsequently in the EU by mid-2018, as well as in several other countries. Since their description as a distinct subset of CD4 + T cells in 1995, natural thymus-derived Tregs have been studied as an instrumental therapeutic approach for controlling undesired immune responses and for reshaping the host immune system toward tolerance [6]. Merging the benefits of CAR technology (redirecting antigen specificity) with Tregs offers a novel and promising therapeutic option for tolerance induction in the context of solid organ or hematopoietic stem cell transplantation (HSCT), as well as other immune-related disorders. However, major challenges remain for developing a standardized, safe, robust, and reliable good manufacturing practice Highlights Advances in the field of cell therapy have led to promising novel approaches to treat malignancies and other debilitating diseases. Redirecting the target antigen specificity of CAR-Treg cells represents one such promising approach. Current manufacturing processes for CAR-Tregs demonstrate challenges in cell purification, yield, expansion, CAR selection and gene delivery, supply chain, and quality control/product release testing. We propose a GMP-compatible manufacturing framework to enhance the standardization and robustness of CAR-Treg production for clinical application.
Post-transplantation cytomegalovirus (CMV) syndrome can be prevented using the antiviral drug (va... more Post-transplantation cytomegalovirus (CMV) syndrome can be prevented using the antiviral drug (val)ganciclovir. (Val)ganciclovir is typically administered following a prophylactic or a pre-emptive strategy. The prophylactic strategy entails early universal administration, the pre-emptive strategy, early treatment in case of infection. However, it is not clear which strategy is superior with respect to transplantation outcome; sex-specific effects of these prevention strategies are not known. We have retrospectively analysed 540 patients from the multi-centre Harmony study along eight pre-defined visits: 308 were treated according to a prophylactic, 232 according to a pre-emptive strategy. As expected, we observed an association of prophylactic strategy with lower incidence of CMV syndrome, delayed onset and lower viral loads compared to the pre-emptive strategy. However, in female patients, the prophylactic strategy was associated with a strong impairment of glomerular filtration ra...
Clinical Journal of the American Society of Nephrology, 2019
Background and objectives The prognostic value of preformed donor-specific HLA antibodies (DSA), ... more Background and objectives The prognostic value of preformed donor-specific HLA antibodies (DSA), which are only detectable by sensitive methods, remains controversial for kidney transplantation. Design, setting, participants, & measurements The outcome of 4233 consecutive kidney transplants performed between 2012 and 2015 in 18 German transplant centers was evaluated. Most centers used a stepwise pretransplant antibody screening with bead array tests and differentiation of positive samples by single antigen assays. Using these screening results, DSA against HLA-A, -B, -C, -DRB1 and -DQB1 were determined. Data on clinical outcome and possible covariates were collected retrospectively. Results Pretransplant DSA were associated with lower overall graft survival, with a hazard ratio of 2.53 for living donation (95% confidence interval [95% CI], 1.49 to 4.29; P<0.001) and 1.59 for deceased donation (95% CI, 1.21 to 2.11; P=0.001). ABO-incompatible transplantation was associated with w...
Background: Acute cellular rejection (ACR) is associated with complications after kidney transpla... more Background: Acute cellular rejection (ACR) is associated with complications after kidney transplantation, such as graft dysfunction and graft loss. Early risk assessment is therefore critical for the improvement of transplantation outcomes. In this work, we retrospectively analyzed a pre-transplant HLA antigen bead assay data set that was acquired by the e:KID consortium as part of a systems medicine approach. Results: The data set included single antigen bead (SAB) reactivity profiles of 52 low-risk graft recipients (negative complement dependent cytotoxicity crossmatch, PRA < 30%) who showed detectable pre-transplant anti-HLA 1 antibodies. To assess whether the reactivity profiles provide a means for ACR risk assessment, we established a novel approach which differs from standard approaches in two aspects: the use of quantitative continuous data and the use of a multiparameter classification method. Remarkably, it achieved significant prediction of the 38 graft recipients who experienced ACR with a balanced accuracy of 82.7% (sensitivity = 76.5%, specificity = 88.9%). Conclusions: The resultant classifier achieved one of the highest prediction accuracies in the literature for pre-transplant risk assessment of ACR. Importantly, it can facilitate risk assessment in non-sensitized patients who lack donor-specific antibodies. As the classifier is based on continuous data and includes weak signals, our results emphasize that not only strong but also weak binding interactions of antibodies and HLA 1 antigens contain predictive information.
Background: BK virus (BKV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivations are ... more Background: BK virus (BKV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivations are common after kidney transplantation and associated with increased morbidity and mortality. Although CMV might be a risk factor for BKV and EBV, the effects of combined reactivations remain unknown. The purpose of this study is to ascertain the interaction and effects on graft function of these reactivations. Methods: 3715 serum samples from 540 kidney transplant recipients were analysed for viral load by qPCR. Measurements were performed throughout eight visits during the first post-transplantation year. Clinical characteristics, including graft function (GFR), were collected in parallel. Findings: BKV had the highest prevalence and viral loads. BKV or CMV viral loads over 10,000 copies•mL −1 led to significant GFR impairment. 57 patients had BKV-CMV combined reactivation, both reactivations were significantly associated (p = 0.005). Combined reactivation was associated with a significant GFR reduction one year post-transplantation of 11.7 mL•min −1 •1.73 m −2 (p = 0.02) at relatively low thresholds (BKV > 1000 and CMV > 4000 copies•mL −1). For EBV, a significant association was found with CMV reactivation (p = 0.02), but no GFR reduction was found. Long cold ischaemia times were a further risk factor for high CMV load. Interpretation: BKV-CMV combined reactivation has a deep impact on renal function one year posttransplantation and therefore most likely on long-term allograft function, even at low viral loads. Frequent viral monitoring and subsequent interventions for low BKV and/or CMV viraemia levels and/or long cold ischaemia time are recommended. Fund: Investigator Initiated Trial; financial support by German Federal Ministry of Education and Research (BMBF).
Chronic kidney disease stage 5 (CKD5) dialysis patients who stay long term in uremic environment ... more Chronic kidney disease stage 5 (CKD5) dialysis patients who stay long term in uremic environment often exhibit several, poorly defined, immune impairments. In this study, we assessed peripheral virus-specific effector/ memory cells and subpopulations of T, B and DC cells using ELISPOT and FACS methods in 74 low-risk kidney transplant candidates without anti-HLA antibodies, prior to transplantation in pre-emptive (never experienced dialysis) and dialysis cohorts. There was difference in circulating marginal zone B cells (MZB) (IgD high CD27 high) between dialysis patients and those receiving kidney grafts pre-emptively (P = .002). Patients treated on dialysis > 12 months had also 4.2-fold greater risk of increased absolute numbers of MZB (95%CI:1.6-11.2; P = .004). There were no other differences in B-, T-and DC-cell subsets. Numbers of effector/memory T cells reactive to major opportunistic virus-specific antigens (CMV, BKV and EBV) were not affected by dialysis. Nonsensitised dialysis-treated patients displayed significantly more circulating MZB compared to those CKD5 patients that had never undergone dialysis therapy.
Background. Recurrent urinary tract infections (UTIs) increase mortality and reduce graft surviva... more Background. Recurrent urinary tract infections (UTIs) increase mortality and reduce graft survival after renal transplantation. Strategies to prevent recurrent UTIs include L-methionine, cranberry juice, and antibiotics. Data on the efficacy of cranberry and L-methionine, however, are controversial in the general population; there are few data in renal transplant recipients. Methods. We performed a retrospective analysis of 82 transplant recipients with recurrent UTIs, who underwent prophylaxis with cranberry juice (2 ϫ 50 mL/d, n ϭ 39, 47.6%), or L-methionine (3 ϫ 500 mg/d, n ϭ 25, 30.5%), or both modalities (n ϭ 18, 21.9%). Thirty patients without prophylaxis served as controls. We analyzed symptoms, pyuria/nitrituria, and incidence of UTI events during 1 year before versus after initiation of prophylaxis. Results. Prophylaxis highly significantly decreased the annual UTI incidence by 58.3% (P Ͻ .001) in the study population with no change in the control group (P ϭ .85); in addition, 53.7% of symptomatic patients reported relief of symptoms and pyuria/nitrituria disappeared in 42.4% of the dipstick-positive patients (P Ͻ .001 each). Cranberry reduced the annual number of UTI episodes by 63.9% from 3.6 Ϯ 1.4 to 1.3 Ϯ 1.3/year (P Ͻ .001) and L-methionine by 48.7% from 3.9 Ϯ 1.8 to 2.0 Ϯ 1.3/year (P Ͻ .001). Conclusion. Cranberry juice and L-methionine successfully reduced the incidence of UTI after renal transplantation.
vival. Conclusions: The risk for mortality after HTx or LuTx is not increased by ESRD, provided t... more vival. Conclusions: The risk for mortality after HTx or LuTx is not increased by ESRD, provided that patients meet access criteria for the KTx waiting list. KTx improves survival in ESRD after HTx or LuTx. BMI and LVEF may predict outcome in HTx/ LuTx patients on the KTx waiting list.
When dealing with T lymphocyte culture there is currently very less information available about t... more When dealing with T lymphocyte culture there is currently very less information available about the interaction between T-cells and the culture system. In this study we look at the influence of the culture chamber on T-cell proliferation in two main aspects of the culture system, namely: culture chamber material and geometry. The study was carried out using unique polymeric closed cell culture inserts, which were processed via injection moulding from polystyrene (PS), polycarbonate (PC), polyetherurethane (PEU), polystyrene-co-acrylonitrile (PSAN) and polyetherimide (PEI). Furthermore culture chamber geometry was studied using commercially available 24, 12 and 6-well plates prepared from tissue culture plastic (TCP). For T lymphocyte stimulation two methods were used involving either EBV peptide pools or MACS iBead particles depending on the experiment performed. Culture was done with 1645 RPMI medium supplemented with foetal calf serum, penicillin, streptomycin and rhIL-2. We found four materials out of five we tested (PS, PC, PSAN and PEI) exhibited similar fold expansions with minimal influence on proportions of CD4 and CD8, while PEU had a negative influence on T cell growth along with adversely affected CD4/CD8 proportions. Changes in the geometry of TCP had no effect on T cell growth or maturation rather the size of geometry seems to have more influence on proliferation. T-cells appear to prefer smaller geometries during initial stages of culture while towards the end of the culture size becomes less significant to cell proliferation. The parameters tested in this study have significant influences on T-cell growth and are necessary to consider when designing and constructing expansion systems for antigen specific T lymphocytes. This is important when culturing T-cells for immunotherapeutic applications where antigen specificity, T-cell maturation and function should remain unaffected during culture.
Little is known about thymus function in transplant patients. Until recently, the phenotype of T ... more Little is known about thymus function in transplant patients. Until recently, the phenotype of T cells that recently emigrated the thymus was unknown. Now it has been demonstrated that CD4(+) recent thymus emigrants coexpress CD31 and CD45RA. Here, we investigated whether uremia and immunosuppression influence CD31(+) CD45RA(+) Th cells before and after kidney transplantation, respectively. Forty-eight renal transplant patients were included receiving either standard triple/quadruple (n = 35) immunosuppression, OKT-3 induction (n = 7) or FTY-720 (n = 6), respectively. Peripheral CD31(+) CD45RA(+) Th cells were quantified flowcytometrically before and at week 1, 4, 12 and 24 post-transplantation. Thirty-nine healthy adults served as controls. CD31(+) CD45RA(+) Th cells correlated inversely with age in patients and controls and were comparable in patients before transplantation and age-matched controls. Importantly, CD31(+) CD45RA(+) Th cell frequencies remained stable during 6 months post-transplantation. In conclusion, CD31(+) CD45RA(+) Th cells are not significantly altered by uremia before and during 6 months of immunosuppressive therapy after kidney transplantation. Implications for thymus function are discussed.
Investigating the health-economic profiles of biomarker-driven immunosuppresion (BIO-DrIM) follow... more Investigating the health-economic profiles of biomarker-driven immunosuppresion (BIO-DrIM) following solid organ transplantation.
Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in kidney transplant recipients (K... more Pneumocystis jirovecii pneumonia (PCP) incidence is increasing in kidney transplant recipients (KTR), but risk factors remain poorly defined. CD4+ T lymphopenia and mannose-binding lectin (MBL) deficiency are common immunodeficiencies in KTR. Here, we investigated whether CD4+ T lymphopenia and/or MBL deficiency would be risk factors for PCP in KTR. Furthermore, the role of thymic function in CD4+ T lymphopenia and outcome was studied by assessing CD45RA+CD31+CD4+ T cell numbers (RTE, recent thymus emigrants). In 321 de novo KTR serial determinations of peripheral T lymphocyte subsets (n=281, mean 4.2 times between days 0-365) and/or MBL levels (n=112, mean 1.8 times between days 30-180) were performed. 22/321 patients developed a PCP episode on average at day 199 (107-398) post-Tx. Age correlated inversely with RTE, CD4+ and CD8+ T-cell counts until day 180 post-Tx. RTE correlated with CD4+ T-cell counts at all time-points pre- and post-Tx. PCP patients had more CMV infections (p=0.045) within the first 3 months compared to controls. Importantly, PCP patients were older (p=0.008), and had lower RTE (p=0.046) pretransplant, and lower CD4+ T-cell counts pretransplant (p=0.017), at day 60 (p=0.032) and for the average of all post-Tx values (p=0.027) compared to controls. Though treatment with T-cell depleting antibodies was associated with consecutive CD4+ T lymphopenia in the whole cohort, the number of patients who received T-cell depleting antibodies was comparable between PCP and control patients (p=0.754). A multivariate stepwise logistic regression model identified only pretransplant CD4+ T-cell counts (OR 0.011, p=0.010) and acute rejection (OR 4.66, p=0.023) as predictors of PCP. In contrast, MBL levels and incidence of MBL deficiency (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;500 ng/ml) at days 30, 90 and 180 post-Tx were not different between PCP patients and controls. In conclusion, PCP risk was associated with higher age and related to both thymic functional impairment and long-lasting CD4+ T-lymphopenia that started already before transplantation. Despite frequent occurrences in KTR, low levels of serum MBL were not associated with increased risk for PCP. CD4+ T-cell counts and function should be addressed in prospective studies for more individualized approaches to PCP prophylaxis.
We compared steady-state pharmacokinetics of mycophenolate mofetil (MMF)-Myfenax Ò (Teva) and Cel... more We compared steady-state pharmacokinetics of mycophenolate mofetil (MMF)-Myfenax Ò (Teva) and CellCept Ò (Roche)-in stable kidney transplant recipients (KTRs). This was an international, multi-centre, randomized, open-label, two-treatment, two-sequence crossover study with a 3-month follow-up. We included KTRs at least 12 months post-transplantation with stable renal graft function for at least 3 months. The maintenance treatment consisted of MMF in combination with tacrolimus with or without steroids. At the end of the two treatment periods, 6-h or 12-h PK studies of mycophenolic acid (MPA) were performed. A total of 43 patients (mean age: 50.7 ± 13.5 years; 19 females, 24 males) were randomized. Estimates of test to reference ratios (90% CIs) were 0.959 (0.899; 1.023) h*lg/ml for AUC (0-tau) and 0.873 (0.787; 0.968) lg/ml for C max. Estimates for AUC (0-6h) were 0.923 (0.865; 0.984) h*lg/ ml and 0.985 (0.877; 1.106) lg/ml for C min. Thus, AUC (0-tau) , AUC (0-6h) , and C min of MPA were within the predefined margins. C max was somewhat outside of these margins in this set of patients. The numbers and types of adverse events were not different between the two treatments. The steady-state pharmacokinetics of MPA as well as adverse events are comparable for Myfenax Ò and CellCept Ò in tacrolimus-treated stable KTRs. (EudraCT-No.: 2009-010562-31; ClinicalTrials.Gov number: NCT00991510)
The success of human induced pluripotent stem cell (hiPSC)-based therapy critically depends on un... more The success of human induced pluripotent stem cell (hiPSC)-based therapy critically depends on understanding and controlling the immunological effects of the hiPSC-derived transplant. While hiPSC-derived cells used for cell therapy are often immature with post-grafting maturation, immunological properties may change, with adverse effects on graft tolerance and control. In the present study, the allogeneic and autologous cellular immunity of hiPSC-derived progenitor and terminally differentiated cells were investigated in vitro. In contrast to allogeneic primary cells, hiPSC-derived early renal progenitors and mature renal epithelial cells are both tolerated not only by autologous but also by allogeneic T cells. These immune-privileged properties result from active immunomodulation and low immune visibility, which decrease during the process of cell maturation. However, autologous and allogeneic natural killer (NK) cell responses are not suppressed by hiPSC-derived renal cells and ef...
Regulatory Tcells (Treg) are essential components of peripheral immune homeostasis. Adoptive Treg... more Regulatory Tcells (Treg) are essential components of peripheral immune homeostasis. Adoptive Treg cell therapy has shown efficacy in a variety of immune-mediated diseases in preclinical studies and is now moving from phase I/IIa to larger phase II studies aiming to demonstrate efficacy. However, hurdles such asin vivostability and efficacy remain to be addressed. Nevertheless, preclinical models have shown that Treg function and specificity can be increased by pharmacological substances or gene modifications, and even that conventional T cells can be converted to Treg potentially providing new sources of Treg and facilitating Treg cell therapy. The exponential growth in genetic engineering techniques and their application to T cells coupled to a large body of knowledge on Treg open numerous opportunities to generate Treg with “superpowers”. This review summarizes the genetic engineering techniques available and their applications for the next-generation of Super-Treg with increased ...
ABSTRACTIntroductionLong-term graft survival rates after renal transplantation are still moderate... more ABSTRACTIntroductionLong-term graft survival rates after renal transplantation are still moderate. We aimed to build an early predictor of an established long-term outcomes marker, the glomerular filtration rate (eGFR) one year post-transplant (eGFR-1y).Materials and MethodsA large cohort of 376 patients was characterized for a multi-level bio-marker panel including gene expression, cytokines, metabolomics and antibody reactivity profiles. Almost one thousand samples from the pre-transplant and early post-transplant period were analysed. Machine learning-based predictors were built employing stacked generalization.ResultsPre-transplant data led to a prediction achieving a Pearson’s correlation coefficient of r=0.39 between measured and predicted eGFR-1y. Two weeks post-transplant, the correlation was improved to r=0.63, and at the third month, to r=0.76. eGFR values were remarkably stable throughout the first year post-transplant and were the best estimators of eGFR-1y already two w...
Background Use of cell-based medicinal products (CBMPs) represents a state-of-the-art approach fo... more Background Use of cell-based medicinal products (CBMPs) represents a state-of-the-art approach for reducing general immunosuppression in organ transplantation. We tested multiple regulatory CBMPs in kidney transplant trials to establish the safety of regulatory CBMPs when combined with reduced immunosuppressive treatment. Methods The ONE Study consisted of seven investigator-led, single-arm trials done internationally at eight hospitals in France, Germany, Italy, the UK, and the USA (60 week follow-up). Included patients were living-donor kidney transplant recipients aged 18 years and older. The reference group trial (RGT) was a standard-of-care group given basiliximab, tapered steroids, mycophenolate mofetil, and tacrolimus. Six non-randomised phase 1/2A cell therapy group (CTG) trials were pooled and analysed, in which patients received one of six CBMPs containing regulatory T cells, dendritic cells, or macrophages; patient selection and immunosuppression mirrored the RGT, except basiliximab induction was substituted with CBMPs and mycophenolate mofetil tapering was allowed. None of the trials were randomised and none of the individuals involved were masked. The primary endpoint was biopsyconfirmed acute rejection (BCAR) within 60 weeks after transplantation; adverse event coding was centralised. The RTG and CTG trials are registered with ClinicalTrials.gov,
Chimeric antigen receptor (CAR) technology and its application to regulatory T cells (Tregs) has ... more Chimeric antigen receptor (CAR) technology and its application to regulatory T cells (Tregs) has been hailed as the next scientific breakthrough in the field of cell and gene therapy. Merging the benefits of CAR technology with Tregs offers a novel and promising therapeutic option for durable reshaping of undesired immune responses following solid organ or hematopoietic stem cell transplantation, as well as in immune-related disorders. However, major challenges remain for developing a standardized, robust, and reliable good manufacturing practice (GMP)-compliant manufacturing process for CAR-Treg cells. We review current progress in the field and recommend ways to improve current CAR-Treg manufacturing processes based on lessons learned from first-generation Treg therapeutics as well as from anticancer CART cell development. The New Era of Cell and Gene Therapy One recent and exciting example of progress in the field of cell and gene therapy has been the ongoing development of chimeric antigen receptor (CAR; see Glossary) technology and its application to regulatory T cells (Tregs) [1-3]. There is a high medical need for more effective and sustainable therapies targeting immune-related diseases as a result of an increase in their prevalence (N10% of chronic diseases) and the high socioeconomic burden associated with managing long-term illness and chronic conditions (e.g., N100 billion €/year in the EU). Adoptive cell transfer (ACT) of Tregs is a promising therapeutic option to reshape immune balance toward tolerance with long-lasting efficacy. First-inhuman (FIH) trials with first-generation thymus Treg cell products have yielded promising data regarding safety and efficacy in immune-related disorders [2,3]. Advances in the development of genetically modified CART cells targeting malignancies will, in all likelihood, also accelerate the clinical translation of CAR-Treg cells [4]. The introduction of costimulatory domains such as cluster of differentiation (CD) molecules CD28 and CD137 has allowed the engineered CART cells to persist and remain active within the body [5]. CART cell therapies have been successfully investigated in a multitude of Phase I and II trials where autologous or allogeneic tumor-specific CART cells were applied. By the end of 2017, these efforts led to marketing approval of two CART cell therapy products, tisagenlecleucel (Kymriah®, Novartis) and axicabtagene ciloleucel (Yescarta®, Kite Pharma/Gilead) in the USA and subsequently in the EU by mid-2018, as well as in several other countries. Since their description as a distinct subset of CD4 + T cells in 1995, natural thymus-derived Tregs have been studied as an instrumental therapeutic approach for controlling undesired immune responses and for reshaping the host immune system toward tolerance [6]. Merging the benefits of CAR technology (redirecting antigen specificity) with Tregs offers a novel and promising therapeutic option for tolerance induction in the context of solid organ or hematopoietic stem cell transplantation (HSCT), as well as other immune-related disorders. However, major challenges remain for developing a standardized, safe, robust, and reliable good manufacturing practice Highlights Advances in the field of cell therapy have led to promising novel approaches to treat malignancies and other debilitating diseases. Redirecting the target antigen specificity of CAR-Treg cells represents one such promising approach. Current manufacturing processes for CAR-Tregs demonstrate challenges in cell purification, yield, expansion, CAR selection and gene delivery, supply chain, and quality control/product release testing. We propose a GMP-compatible manufacturing framework to enhance the standardization and robustness of CAR-Treg production for clinical application.
Post-transplantation cytomegalovirus (CMV) syndrome can be prevented using the antiviral drug (va... more Post-transplantation cytomegalovirus (CMV) syndrome can be prevented using the antiviral drug (val)ganciclovir. (Val)ganciclovir is typically administered following a prophylactic or a pre-emptive strategy. The prophylactic strategy entails early universal administration, the pre-emptive strategy, early treatment in case of infection. However, it is not clear which strategy is superior with respect to transplantation outcome; sex-specific effects of these prevention strategies are not known. We have retrospectively analysed 540 patients from the multi-centre Harmony study along eight pre-defined visits: 308 were treated according to a prophylactic, 232 according to a pre-emptive strategy. As expected, we observed an association of prophylactic strategy with lower incidence of CMV syndrome, delayed onset and lower viral loads compared to the pre-emptive strategy. However, in female patients, the prophylactic strategy was associated with a strong impairment of glomerular filtration ra...
Clinical Journal of the American Society of Nephrology, 2019
Background and objectives The prognostic value of preformed donor-specific HLA antibodies (DSA), ... more Background and objectives The prognostic value of preformed donor-specific HLA antibodies (DSA), which are only detectable by sensitive methods, remains controversial for kidney transplantation. Design, setting, participants, & measurements The outcome of 4233 consecutive kidney transplants performed between 2012 and 2015 in 18 German transplant centers was evaluated. Most centers used a stepwise pretransplant antibody screening with bead array tests and differentiation of positive samples by single antigen assays. Using these screening results, DSA against HLA-A, -B, -C, -DRB1 and -DQB1 were determined. Data on clinical outcome and possible covariates were collected retrospectively. Results Pretransplant DSA were associated with lower overall graft survival, with a hazard ratio of 2.53 for living donation (95% confidence interval [95% CI], 1.49 to 4.29; P<0.001) and 1.59 for deceased donation (95% CI, 1.21 to 2.11; P=0.001). ABO-incompatible transplantation was associated with w...
Background: Acute cellular rejection (ACR) is associated with complications after kidney transpla... more Background: Acute cellular rejection (ACR) is associated with complications after kidney transplantation, such as graft dysfunction and graft loss. Early risk assessment is therefore critical for the improvement of transplantation outcomes. In this work, we retrospectively analyzed a pre-transplant HLA antigen bead assay data set that was acquired by the e:KID consortium as part of a systems medicine approach. Results: The data set included single antigen bead (SAB) reactivity profiles of 52 low-risk graft recipients (negative complement dependent cytotoxicity crossmatch, PRA < 30%) who showed detectable pre-transplant anti-HLA 1 antibodies. To assess whether the reactivity profiles provide a means for ACR risk assessment, we established a novel approach which differs from standard approaches in two aspects: the use of quantitative continuous data and the use of a multiparameter classification method. Remarkably, it achieved significant prediction of the 38 graft recipients who experienced ACR with a balanced accuracy of 82.7% (sensitivity = 76.5%, specificity = 88.9%). Conclusions: The resultant classifier achieved one of the highest prediction accuracies in the literature for pre-transplant risk assessment of ACR. Importantly, it can facilitate risk assessment in non-sensitized patients who lack donor-specific antibodies. As the classifier is based on continuous data and includes weak signals, our results emphasize that not only strong but also weak binding interactions of antibodies and HLA 1 antigens contain predictive information.
Background: BK virus (BKV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivations are ... more Background: BK virus (BKV), Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivations are common after kidney transplantation and associated with increased morbidity and mortality. Although CMV might be a risk factor for BKV and EBV, the effects of combined reactivations remain unknown. The purpose of this study is to ascertain the interaction and effects on graft function of these reactivations. Methods: 3715 serum samples from 540 kidney transplant recipients were analysed for viral load by qPCR. Measurements were performed throughout eight visits during the first post-transplantation year. Clinical characteristics, including graft function (GFR), were collected in parallel. Findings: BKV had the highest prevalence and viral loads. BKV or CMV viral loads over 10,000 copies•mL −1 led to significant GFR impairment. 57 patients had BKV-CMV combined reactivation, both reactivations were significantly associated (p = 0.005). Combined reactivation was associated with a significant GFR reduction one year post-transplantation of 11.7 mL•min −1 •1.73 m −2 (p = 0.02) at relatively low thresholds (BKV > 1000 and CMV > 4000 copies•mL −1). For EBV, a significant association was found with CMV reactivation (p = 0.02), but no GFR reduction was found. Long cold ischaemia times were a further risk factor for high CMV load. Interpretation: BKV-CMV combined reactivation has a deep impact on renal function one year posttransplantation and therefore most likely on long-term allograft function, even at low viral loads. Frequent viral monitoring and subsequent interventions for low BKV and/or CMV viraemia levels and/or long cold ischaemia time are recommended. Fund: Investigator Initiated Trial; financial support by German Federal Ministry of Education and Research (BMBF).
Chronic kidney disease stage 5 (CKD5) dialysis patients who stay long term in uremic environment ... more Chronic kidney disease stage 5 (CKD5) dialysis patients who stay long term in uremic environment often exhibit several, poorly defined, immune impairments. In this study, we assessed peripheral virus-specific effector/ memory cells and subpopulations of T, B and DC cells using ELISPOT and FACS methods in 74 low-risk kidney transplant candidates without anti-HLA antibodies, prior to transplantation in pre-emptive (never experienced dialysis) and dialysis cohorts. There was difference in circulating marginal zone B cells (MZB) (IgD high CD27 high) between dialysis patients and those receiving kidney grafts pre-emptively (P = .002). Patients treated on dialysis > 12 months had also 4.2-fold greater risk of increased absolute numbers of MZB (95%CI:1.6-11.2; P = .004). There were no other differences in B-, T-and DC-cell subsets. Numbers of effector/memory T cells reactive to major opportunistic virus-specific antigens (CMV, BKV and EBV) were not affected by dialysis. Nonsensitised dialysis-treated patients displayed significantly more circulating MZB compared to those CKD5 patients that had never undergone dialysis therapy.
Background. Recurrent urinary tract infections (UTIs) increase mortality and reduce graft surviva... more Background. Recurrent urinary tract infections (UTIs) increase mortality and reduce graft survival after renal transplantation. Strategies to prevent recurrent UTIs include L-methionine, cranberry juice, and antibiotics. Data on the efficacy of cranberry and L-methionine, however, are controversial in the general population; there are few data in renal transplant recipients. Methods. We performed a retrospective analysis of 82 transplant recipients with recurrent UTIs, who underwent prophylaxis with cranberry juice (2 ϫ 50 mL/d, n ϭ 39, 47.6%), or L-methionine (3 ϫ 500 mg/d, n ϭ 25, 30.5%), or both modalities (n ϭ 18, 21.9%). Thirty patients without prophylaxis served as controls. We analyzed symptoms, pyuria/nitrituria, and incidence of UTI events during 1 year before versus after initiation of prophylaxis. Results. Prophylaxis highly significantly decreased the annual UTI incidence by 58.3% (P Ͻ .001) in the study population with no change in the control group (P ϭ .85); in addition, 53.7% of symptomatic patients reported relief of symptoms and pyuria/nitrituria disappeared in 42.4% of the dipstick-positive patients (P Ͻ .001 each). Cranberry reduced the annual number of UTI episodes by 63.9% from 3.6 Ϯ 1.4 to 1.3 Ϯ 1.3/year (P Ͻ .001) and L-methionine by 48.7% from 3.9 Ϯ 1.8 to 2.0 Ϯ 1.3/year (P Ͻ .001). Conclusion. Cranberry juice and L-methionine successfully reduced the incidence of UTI after renal transplantation.
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Papers by Petra Reinke