Five-year follow-up of a phase I trial of donor-derived modified immune cell infusion in kidney transplantation.

Background: The administration of modified immune cells (MIC) before kidney transplantation led to specific immunosuppression against the allogeneic donor and a significant increase in regulatory B lymphocytes. We wondered how this approach affected the continued clinical course of these patients. Methods: Ten patients from a phase I clinical trial who had received MIC infusions prior to kidney transplantation were retrospectively compared to 15 matched standard-risk recipients. Follow-up was until year five after surgery. Results: The 10 MIC patients had an excellent clinical course with stable kidney graft function, no donor-specific human leukocyte antigen antibodies (DSA) or acute rejections, and no opportunistic infections. In comparison, a retrospectively matched control group receiving standard immunosuppressive therapy had a higher frequency of DSA (log rank P = 0.046) and more opportunistic infections (log rank P = 0.033). Importantly, MIC patients, and in particular the four patients who had received the highest cell number 7 days before surgery and received low immunosuppression during follow-up, continued to show a lack of anti-donor T lymphocyte reactivity in vitro and high CD19+CD24hiCD38hi transitional and CD19+CD24hiCD27+ memory B lymphocytes until year five after surgery. Conclusions: MIC infusions together with reduced conventional immunosuppression were associated with good graft function during five years of follow-up, no de novo DSA development and no opportunistic infections. In the future, MIC infusions might contribute to graft protection while reducing the side effects of immunosuppressive therapy. However, this approach needs further validation in direct comparison with prospective controls. Trial registration: https://clinicaltrials.gov/, identifier NCT02560220 (for the TOL-1 Study). EudraCT Number: 2014-002086-30.

Induction of Long-Lasting Regulatory B Lymphocytes by Modified Immune Cells in Kidney Transplant Recipients.

BACKGROUND: We recently demonstrated that donor-derived modified immune cells (MICs)-PBMCs that acquire immunosuppressive properties after a brief treatment-induced specific immunosuppression against the allogeneic donor when administered before kidney transplantation. We found up to a 68-fold increase in CD19 + CD24 hi CD38 hi transitional B lymphocytes compared with transplanted controls. METHODS: Ten patients from a phase 1 clinical trial who had received MIC infusions before kidney transplantation were followed to post-transplant day 1080. RESULTS: Patients treated with MICs had a favorable clinical course, showing no donor-specific human leukocyte antigen antibodies or acute rejections. The four patients who had received the highest dose of MICs 7 days before surgery and were on reduced immunosuppressive therapy showed an absence of in vitro lymphocyte reactivity against stimulatory donor blood cells, whereas reactivity against third party cells was preserved. In these patients, numbers of transitional B lymphocytes were 75-fold and seven-fold higher than in 12 long-term survivors on minimal immunosuppression and four operationally tolerant patients, respectively ( P <0.001 for both). In addition, we found significantly higher numbers of other regulatory B lymphocyte subsets and a gene expression signature suggestive of operational tolerance in three of four patients. In MIC-treated patients, in vitro lymphocyte reactivity against donor blood cells was restored after B lymphocyte depletion, suggesting a direct pathophysiologic role of regulatory B lymphocytes in donor-specific unresponsiveness. CONCLUSIONS: These results indicate that donor-specific immunosuppression after MIC infusion is long-lasting and associated with a striking increase in regulatory B lymphocytes. Donor-derived MICs appear to be an immunoregulatory cell population that when administered to recipients before transplantation, may exert a beneficial effect on kidney transplants. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: MIC Cell Therapy for Individualized Immunosuppression in Living Donor Kidney Transplant Recipients (TOL-1), NCT02560220.

Individualised immunosuppression with intravenously administered donor-derived modified immune cells compared with standard of care in living donor kidney transplantation (TOL-2 Study): protocol for a multicentre, open-label, phase II, randomised controlled trial.

INTRODUCTION: Donor-derived modified immune cells (MIC) induced long-term specific immunosuppression against the allogeneic donor in preclinical models of transplantation. In a phase I clinical trial (TOL-1 Study), MIC treatment resulted in a cellular phenotype that was directly and indirectly suppressive to the recipient's immune system allowing for reduction of conventional immunosuppressive therapy. Here, we describe a protocol for a randomised controlled, multicentre phase-IIb clinical trial of individualised immunosuppression with intravenously administered donor MIC compared with standard-of-care (SoC) in living donor kidney transplantation (TOL-2 Study). METHODS AND ANALYSIS: Sixty-three living donor kidney transplant recipients from six German transplant centres are randomised 2:1 to treatment with MIC (MIC group, N=42) or no treatment with MIC (control arm, N=21). MIC are manufactured from donor peripheral blood mononuclear cells under Good Manufacturing Practice conditions. The primary objective of this trial is to determine the efficacy of MIC treatment together with reduced conventional immunosuppressive therapy in terms of achieving an operational tolerance-like phenotype compared with SoC 12 months after MIC administration. Key secondary endpoints are the number of patient-relevant infections as well as a composite of biopsy-proven acute rejection, graft loss, graft dysfunction or death. Immunosuppressive therapy of MIC-treated patients is reduced during follow-up under an extended immunological monitoring including human leucocyte antigen-antibody testing, and determination of lymphocyte subsets, for example, regulatory B lymphocytes (Breg) and antidonor T cell response. A Data Safety Monitoring Board has been established to allow an independent assessment of safety and efficacy. ETHICS AND DISSEMINATION: Ethical approval has been provided by the Ethics Committee of the Medical Faculty of the University of Heidelberg, Heidelberg, Germany (AFmu-580/2021, 17 March 2022) and from the Federal Institute for Vaccines and Biomedicines, Paul-Ehrlich-Institute, Langen, Germany (Vorlage-Nr. 4586/02, 21 March 2022). Written informed consent will be obtained from all patients and respective donors prior to enrolment in the study. The results from the TOL-2 Study will be published in peer-reviewed medical journals and will be presented at symposia and scientific meetings. TRIAL REGISTRATION NUMBER: NCT05365672.

CD4+CD25+CD127-Foxp3+ and CD8+CD28- Tregs in Renal Transplant Recipients: Phenotypic Patterns, Association With Immunosuppressive Drugs, and Interaction With Effector CD8+ T Cells and CD19+IL-10+ Bregs.

Introduction: Gaps still exist regarding knowledge on regulatory cells in transplant recipients. We studied the phenotypic patterns of CD4+, CD8+CD28- Tregs, and CD19+IL-10+ Bregs in the blood of healthy controls (HC), end-stage kidney disease patients (ESKD), early and late stable renal transplant recipients (Tx), and transplant recipients with steroid-treated acute cellular rejection 1 week-3 months after successful treatment. We also investigated the relationship between immunosuppressive drugs and the aforementioned regulatory cells in transplant recipients. Methods: We recruited 32 HC, 83 ESKD, 51 early Tx, 95 late Tx, and 9 transplant patients with a recent steroid-treated acute cellular rejection. Besides CD19+IL-10+ Bregs, we analyzed absolute and relative frequencies of CD4+CD25+CD127-Foxp3+ Tregs and CD8+CD28- Tregs and their expression of IL-10, TGF-ß, IFN-g, and Helios. Results: We found a negative correlation between absolute CD4+CD25+CD127-Foxp3+ Treg and relative CD19+IL-10+ Breg frequencies in early Tx recipients (r=-0.433, p=0.015, n=31). In that group, absolute CD4+CD25+CD127-Foxp3+ Tregs were negatively associated with steroid dose and tacrolimus trough levels (r=-0.377, p = 0.021, n=37; r=-0.43, p=0.033, n=25, respectively), opposite to IL-10+ Bregs, whose frequency apparently was not negatively affected by potent immunosuppression early posttransplant. We found also lower CD4+CD25+CD127-Foxp3+ Tregs in patients treated with basiliximab or rATG as compared with ESKD patients (p=0.001 and p <0.001, respectively). No difference in absolute IL-10+ Bregs could be detected among these 3 patient groups. Early Tx recipients showed lower CD4+CD25+CD127-Foxp3+ Tregs within 3 months of antibody induction than after 3 months (p = 0.034), whereas IL-10+ Bregs showed higher relative counts during the first 3 months post antibody induction than after 3 months (p = 0.022). Our findings suggest that IL-10+ Bregs decrease with time posttransplantation independent of the effect of antibody induction and dose of other immunosuppressive drugs. Conclusion: These findings suggest that CD19+IL-10+ Bregs and CD4+CD25+CD127-Foxp3+ Tregs behave in opposite ways during the early posttransplant period, possibly due to a predominant negative impact of high doses of immunosuppressants on Tregs. CD19+IL-10+Bregs do not seem to be suppressed by antibody induction and early potent immunosuppression with chemical drugs.

Relationship of transitional regulatory B and regulatory T cells and immunosuppressive drug doses in stable renal transplant recipients.

OBJECTIVES: Regulatory B cells (Bregs) and T cells (Tregs) are thought to be involved in the regulation of graft acceptance in renal transplant recipients. However, mechanisms that affect Breg differentiation and interaction with Tregs are rather unclear. METHODS: Using eight-color-fluorescence flow cytometry, Tregs and CD19+ CD24hiCD38hi Bregs were analyzed in whole blood samples of 80 stable kidney transplant recipients, 20 end-stage renal disease (ESRD) patients and 32 healthy controls (HC). In addition, differentiation of Bregs and Tregs was studied in different micromilieus using cocultures with strongly enriched B-lymphocytes and autologous peripheral blood mononuclear cells stimulated with CpG and phytohemagglutinin. RESULTS: Bregs were higher in HC than in ESRD patients and lowest in transplant recipients. Bregs were higher early as compared to late posttransplant. Posttransplant, high Bregs were associated with higher glomerular filtration rate (GFR) and lower C-reactive protein (CRP). Higher doses and blood levels of ciclosporine, tacrolimus, and mycophenolate mofetil as well as higher doses of steroids were not associated with low Bregs. In contrast, most Treg subsets were lower when blood levels of ciclosporine, tacrolimus, and mycophenolate mofetil were higher. Tregs were not associated with Bregs, GFR, CRP plasma levels, and occurrence of rejection or infection. In vitro, differentiation of Bregs was strongly dependent on T cell support and was blocked by excessive or lacking T-cell help. Tregs were not associated with Breg numbers in vitro. CONCLUSION: Bregs appear to be insensitive to high doses of posttransplant immunosuppressive drugs. The protracted Breg decrease posttransplant might be caused by impaired T cell support attributable to immunosuppressive drugs.

Higher CD19+CD25+ Bregs are independently associated with better graft function in renal transplant recipients.

BACKGROUND: The Identification of B cell subsets with regulatory functions might open the way to new therapeutic strategies in the field of transplantation, which aim to reduce the dose of immunosuppressive drugs and prolong the graft survival. CD25 was proposed as a marker of a B-cell subset with an immunosuppressive action termed Bregs. The effect of CD19 + CD25 + Bregs on graft function in renal transplant recipients has not yet been elucidated. We investigated a potential impact of CD19 + CD25 + Bregs on renal graft function as well as a possible interaction of CD19 + CD25 + Bregs with peripheral Tregs in healthy controls, end-stage kidney disease patients (ESKD), and renal transplant recipients. Moreover, we aimed to investigate the association of CD19 + CD25 + Bregs with serum IL-10, TGF-ß1, and IFN-γ in the same study groups. METHOD: Thirty-one healthy controls, ninety renal transplant recipients, and eighteen ESKD patients were enrolled. We evaluated the CD19 + CD25 + Bregs and Treg absolute counts. Next, we investigated CD19 + CD25 + Bregs as predictors of good graft function in multiple regression and ROC analyses. Finally, we evaluated the association between CD19 + CD25+ Bregs and serum IL-10, TGF-ß, and IFN-γ. RESULTS: ESKD patients and renal transplant recipients showed lower counts of CD19 + CD25+ Bregs compared to healthy controls (p < 0.001). Higher CD19 + CD25+ Breg counts were independently associated with a better GFR in renal transplant recipients (unstandardized B coefficient = 9, p = 0.02). In these patients, higher CD19 + CD25+ Bregs were independently associated with higher Treg counts (unstandardized B = 2.8, p = 0.004). In ROC analysis, cut-offs for CD19 + CD25 + Breg counts and serum TGF-ß1 of 0.12 cell/µl and 19,635.4 pg/ml, respectively, were shown to provide a good sensitivity and specificity in identifying GFR ≥ 30 ml/min (AUC = 0.67, sensitivity 77%, specificity 43%; AUC = 0.65, sensitivity 81%, specificity 50%, respectively). Finally, a significant positive association between CD19 + CD25+ Bregs and TGF-ß1 was shown in renal transplant recipients (r = 0.255, p = 0.015). CONCLUSIONS: Our findings indicate that higher counts of CD19 + CD25+ Bregs are independently associated with better renal function and higher absolute Treg counts in renal transplant recipients.

Circulating NKG2A-NKG2D+ CD56dimCD16+ Natural Killer (NK) Cells as Mediators of Functional Immunosurveillance in Kidney Transplant Recipients.

BACKGROUND Recently, in patients with long-term functioning allografts, we showed that high NKG2D+ NK cell numbers in the peripheral blood were associated with a higher glomerular filtration rate, whereas high NKG2A+ NK cells were associated with a lower glomerular filtration rate. Both NK cell determinants react with ligands (MIC A/B, HLA-E) expressed on stressed cells, such as virus-infected cells, tumor cells, or cells activated during graft rejection. In the present study, we attempted to characterize these 2 NK cell subsets further. MATERIAL AND METHODS Using flow cytometry, NK cell subsets were analyzed in whole-blood samples of 35 stable kidney transplant recipients (serum creatinine mean±SD: 1.44±0.45 mg/dl). Blood was obtained 95-3786 days after transplant (mean±SD: 1168±1011 days after transplant). RESULTS High proportions of NKG2A-NKG2D+ NK cells were strongly associated with high numbers of CD56dimCD16+ (p=0.001) NK cells co-expressing CD107 (P=0.001) and granzyme B (P=0.045), suggesting that NKG2A-NKG2D+ NK cells are predominantly cytotoxic. In contrast, high numbers of NKG2A+NKG2D- NK cells were strongly associated with low numbers of CD56dimCD16+ NK cells expressing CD107 (P=0.026), CD25 (p=0.008), TGF-ßR (P=0.028), and TGF-ß (P=0.005), suggesting that patients with high proportions of NKG2A+NKG2D- NK cells have low proportions of NK cell subsets with cytotoxic phenotype. CONCLUSIONS A high proportion of NKG2A+NKG2D- NK cells is associated with decreased counts of NKG2A-NKG2D+ CD56dimCD16+ cytotoxic NK cells in the circulation. This may result in impaired immunosurveillance. We would like to hypothesize that NKG2A-NKG2D+ CD56dimCD16+ cytotoxic NK cells eliminate MIC A/B-expressing stressed cells which possess a potential to harm the transplant. Further studies will have to evaluate whether the proportion of NKG2A-NKG2D+ CD56dimCD16+ cytotoxic NK cells is a useful biomarker for the prediction of an uncomplicated postoperative course in kidney transplant recipients.

NK cell subsets in idiopathic recurrent miscarriage and renal transplant patients.

The present review article compares NK cell subsets and cytokine patterns determined in the peripheral blood as well as results of functional in-vitro assays using peripheral NK cells of idiopathic recurrent miscarriage (iRM) patients with corresponding results obtained in female healthy controls and female renal transplant recipients with good long-term graft function. Immune mechanisms, inducing transplant rejection in long-term transplant recipients might also be able to induce rejection of semi-allogeneic fetal cells in patients with iRM. Consequently, the immune status of transplant recipients with good stable long-term graft function should be different from the immune status of iRM patients. iRM patients show a strong persistent cytotoxic NK cell response in the periphery. Simultaneously, immunostimulatory Th1 as well as immunosuppressive Th2 type lymphocytes in the blood are strongly activated but plasma levels of immunosuppressive Th2 type cytokines are abnormally low. In-vitro, unstimulated NK cell cultures of iRM patients show a strong spontaneous TGF-ß1 release in the supernatant but lower TGF-ß1 levels after stimulation with tumor cell line K562, suggesting strong consumption of TGF-ß1 by pre-activated NK cells of iRM patients that might contribute to the low systemic Th2 type plasma levels. iRM patients do not show a systemic switch to a Th2 type cytokine pattern and one might hypothesize that low TGF-ß plasma levels indicate low TGF-ß levels in the micromilieu immediately before fetal rejection. Persistent TGF-ß deficiency implies a persistent unfavorable micromilieu for pregnancy resulting in failing tolerance induction due to lack of TGF-ß, a condition that might contribute to iRM.

Phase I trial of donor-derived modified immune cell infusion in kidney transplantation.

BACKGROUNDPreclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor.METHODSIn this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day -2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day -2 (n = 3, group B) or day -7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360.RESULTSMIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature.CONCLUSIONMIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs.TRIAL REGISTRATIONEudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220.FUNDINGFederal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany.

Patients with idiopathic recurrent miscarriage have abnormally high TGFß+ blood NK, NKT and T cells in the presence of abnormally low TGFß plasma levels.

BACKGROUND: Previously, we demonstrated up-regulated activated CD4+ and CD8+ T lymphocytes as well as up-regulated cytotoxic NK cells in the blood of patients with idiopathic recurrent miscarriage. In the present study, we tried to identify deficiencies in counter-regulating immune mechanisms of these patients. METHOD: Cytokines were determined in NK cells and in plasma samples of 35 healthy controls, 33 patients with idiopathic recurrent miscarriage, 34 patients with end stage renal disease, 10 transplant patients early and 37 transplant patients late post-transplant using flow-cytometry and luminex. In addition, cytokines were studied in supernatants of cell cultures with peripheral blood mononuclear cells stimulated in-vitro with tumor cell line K562. RESULTS: Patients with idiopathic recurrent miscarriage exhibited the highest absolute cell counts of circulating TGFß1+ NK, NKT and T lymphocytes and the lowest TGFß1 plasma levels of all study groups (for all p < 0.050). In-vitro, peripheral blood mononuclear cells of patients with idiopathic recurrent miscarriage showed high spontaneous TGFß1 production that could not be further increased by stimulation with K562, indicating increased consumption of TGFß1 by activated cells in the cell culture. Moreover, patients with idiopathic recurrent miscarriage had abnormally high IL4+ as well as abnormally high IFNy+ NK cells (p < 0.010) but similar IL10+ NK cell numbers as female healthy controls and showed the lowest plasma levels of IL10, TGFß3, IL1RA, IL1ß, IL5, IL6, IL8, IL17, TNFα, GM-CSF, TPO and VEGF and the highest plasma levels of G-CSF, FGF-basic, CCL3 and CXCL5 as compared to female HC and female transplant recipients (for all p < 0.050). CONCLUSIONS: Patients with idiopathic recurrent miscarriage show an activated immune system that can hardly be stimulated further and cannot be efficiently down-regulated by up-regulated TGFß1+ and IL4+ NK, NKT and T lymphocytes which are present concomitantly in these patients. The strongly decreased TGFß and IL10 plasma levels indicate deficient down-regulation and reflect a dysbalance of the immune system in patients with idiopathic recurrent miscarriage. These findings may be relevant for explaining the pathogenesis of idiopathic recurrent miscarriage.

Donor organ intervention before kidney transplantation: Head-to-head comparison of therapeutic hypothermia, machine perfusion, and donor dopamine pretreatment. What is the evidence?

Therapeutic hypothermia, hypothermic pulsatile machine perfusion (MP), and renal-dose dopamine administered to stable brain-dead donors have shown efficacy to reduce the dialysis requirement after kidney transplantation. In a head-to-head comparison of the three major randomized controlled trials in this field, we estimated the number-needed-to-treat for each method, evaluated costs and inquired into special features regarding long-term outcomes. The MP and hypothermia trials used any dialysis requirement during the first postoperative week, whereas the dopamine trial assessed >1 dialysis session as primary endpoint. Compared to controls, the respective rates declined by 5.7% with MP, 10.9% with hypothermia, and 10.7% with dopamine. Costs to prevent one endpoint in one recipient amount to approximately $17 000 with MP but are negligible with the donor interventions. MP resulted in a borderline significant difference of 4% in 3-year graft survival, but a point of interest is that the preservation method was switched in 25 donors (4.6%) for technical reasons. Graft survival was not improved with dopamine on intention-to-treat but suggested an exposure-response relationship with infusion time. MP was less efficacious and cost-effective to prevent posttransplant dialysis. Whether the benefit on early graft dysfunction achieved with any method will improve long-term graft survival remains to be established.

Pretransplant Cancer in Kidney Recipients in Relation to Recurrent and De Novo Cancer Incidence Posttransplantation and Implications for Graft and Patient Survival.

BACKGROUND: Whether kidney transplant recipients who were treated for a malignant tumor before transplantation are at an increased risk of developing a tumor posttransplantation has not been adequately quantified and characterized. METHODS: We studied more than 270 000 patients on whom pretransplant and posttransplant malignancy data were reported to the Collaborative Transplant Study. More than 4000 of these patients were treated for pretransplant malignancy. The posttransplant tumor incidence in these patients was compared to that in recipients without a pretransplant tumor. Cox regression, considering multiple confounders, was applied. RESULTS: Significant increases in posttransplant tumor incidence with hazard ratio ranging from 2.10 to 5.47 (all P < 0.001) were observed for tumors in the site-specific pretransplant locations, suggesting tumor recurrences. There were also significantly increased de novo tumors in new locations with hazard ratio ranging from 1.28 to 1.89. Pretransplant basal cell carcinoma of the skin and male genital cancer were associated with significantly increased death-censored graft survival, suggesting impaired immune responsiveness against transplanted kidneys. Time interval from pretransplant tumor occurrence to transplantation and posttransplant mammalian target of rapamycin inhibitor treatment was not found to be of significant relevance in this study. CONCLUSIONS: Patients who experienced a pretransplant tumor are at significant risk of tumor recurrence, regardless of the length of interval between tumor treatment and transplantation. There is also some increased risk for de novo tumors, suggesting impaired immune surveillance. Impaired tumor immunity appears to extend to a lower rate of transplant rejection because patients with pretransplant tumors tended to show improved death-censored graft survival.

Pulse Pressure and Outcome in Kidney Transplantation: Results From the Collaborative Transplant Study.

BACKGROUND: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) are important predictors of graft and patient survival in renal transplantation. Pulse pressure (PP), the difference between systolic and diastolic pressure, has been associated with cardiovascular and renal morbidity in nontransplant epidemiological studies and clinical trials. METHODS: In this large retrospective analysis of prospectively collected data, transplant recipients from 1995 to 2015 were examined for patient and death-censored graft survival. RESULTS: In 43 006 recipients, a higher 1-year PP was significantly associated with inferior 10-year patient and death-censored graft survival. In patients 60 years or older, SBP but not DBP was associated with 10-year survival, an effect that was pronounced in patients with a normal SBP of <140 mm Hg and an increased PP of 60 mm Hg or greater, highlighting the superior impact of PP on survival in elderly recipients. In recipients 60 years or older, higher PP was associated with increased mortality due to circulatory system diseases but not to infection or cancer. The combination of PP 60 mm Hg or greater and high SBP of 140 mm Hg or greater showed the strongest association with death-censored graft survival across all age groups. CONCLUSIONS: We found convincing evidence that PP 1-year posttransplant is predictive of patient survival, especially in elderly recipients with normal SBP. Combined analysis of SBP and PP showed that high PP confers additional predictive information for patient survival beyond that derived from analysis of SBP alone. With regard to prediction of death-censored graft survival, the combination of high SBP and high PP showed the best correlation across all age groups.

No Increase in Colon Cancer Risk Following Induction with Neu5Gc-Bearing Rabbit Anti-T Cell IgG (ATG) in Recipients of Kidney Transplants.

Because of a mutation of the gene allowing the synthesis of the Neu5Gc form of neuraminidic acid, humans lack the Neu5Gc present in other mammals and develop anti-Neu5Gc. However, humans can absorb dietary Neu5Gc and normal colon epithelium displays minute amounts of Neu5Gc. The potential "physiological" formation of in situ immune complexes has been proposed as a risk factor for colon cancer and as the link between red meat-rich diet and colon carcinoma. In this article, we took advantage of evidence that polyclonal rabbit IgG (ATG) elicits an immune response against Neu5Gc and we consulted a large data base of allograft recipients treated or not with animal-derived IgG to discuss this hypothesis. Based on data from 173,960 and 38,505 patients without and with ATG induction, respectively, we found no evidence that exposure to higher levels of anti-Neu5Gc is associated with a higher incidence of colon carcinoma.

The Risk of Failure With HLA Mismatch and Recipient Age in First Pediatric (<18 years) Kidney Transplants.

BACKGROUND: Even in the modern era of kidney transplantation with improved surgical techniques, immunosuppression, and clinical care, HLA matching has been shown to be important in allograft survival in adults who receive an organ from either a deceased or living donor. We now explore the impact of genetic matching in pediatric first-kidney transplants. METHODS: Using the United Network for Organ Sharing data, we identified 18 602 first pediatric (<18 years) kidney transplants between October 1, 1987, and December 31, 2016. Recipients were classified by number of HLA mismatches and donor origin. Cox proportional hazard analyses, adjusting for recipient and donor transplant covariates, were performed to study the impact of HLA on kidney allograft survival. RESULTS: For the fully adjusted Cox model there was a 30% increase in the hazard of allograft failure for 1 HLA mismatch, when compared with 0 mismatched recipients, and a 92% increase in risk for 6 mismatches. Although pediatric allografts from living donors survive as long or longer than those from deceased persons, they have a higher hazard of failure as a function of HLA mismatch. Kidney allografts from deceased donors HLA mismatched 0 to 3 were found to survive as long as organs from living donors HLA mismatched 4 to 6. In the full Cox model, there was a strong, linear effect on the hazard of allograft failure with quartile of age such that the youngest patients at age of transplant had the longest surviving grafts. CONCLUSIONS: HLA plays an important role in the survival of first pediatric kidney transplants. The better the match, and the earlier the transplant is performed in the child's life, the lower is the risk that the organ will fail.

Changes of NK cell subsets with time post-transplant in peripheral blood of renal transplant recipients.

BACKGROUND: There is evidence that NK cells with low cytotoxicity but strong immunoregulatory characteristics contribute to good graft outcome. We attempted to investigate which NK cell subsets increase post-transplant and might affect graft function. METHOD: Lymphocyte and NK cell subsets were determined in whole blood using eight-colour-fluorescence flow cytometry in patients pre-transplant and post-transplant. In total, 31 transplant recipients were studied. RESULTS: When cell numbers were compared in 9 patients pre- and 6 months post-transplant, post-transplant CD56dimCD16+ (p = 0.011) NK cells with the phenotype CD158a+ (p = 0.008), CD158e+ (p = 0.038), NKG2A+ (p = 0.008), NKG2D+ (p = 0.011), IFNyR+ (p = 0.008), perforin+ (p = 0.008), granzymeB+ (p = 0.008), perforin+granzymeB+ (p = 0.008) and perforin-granzymeB- (p = 0.021) were lower than those pre-transplant, indicating a post-transplant reduction of cytotoxic NK cells. In 28 patients NK cell subsets were analyzed with respect to time post-transplant (median 888 days post-transplant). CD56dimCD16+ NK cells co-expressing CD158a (p = 0.014), NKG2D (p = 0.047), IL4R (p = 0.038), IL10R (p = 0.008) and IFNy (p = 0.036) as well as CD56bright NK cells with the phenotype TGFß+ (p = 0.017), TGFR+ (p = 0.035), CD158a+ (p = 0.042) and perforin-granzymeB- (p = 0.048) increased with time post-transplant. CONCLUSION: Post-transplant, cytotoxic NK cells were lower than pre-transplant and remained low, whereas NK cell subsets with potentially immunoregulatory properties increased.

Long- and short-term outcomes in renal allografts with deceased donors: A large recipient and donor genome-wide association study.

Improvements in immunosuppression have modified short-term survival of deceased-donor allografts, but not their rate of long-term failure. Mismatches between donor and recipient HLA play an important role in the acute and chronic allogeneic immune response against the graft. Perfect matching at clinically relevant HLA loci does not obviate the need for immunosuppression, suggesting that additional genetic variation plays a critical role in both short- and long-term graft outcomes. By combining patient data and samples from supranational cohorts across the United Kingdom and European Union, we performed the first large-scale genome-wide association study analyzing both donor and recipient DNA in 2094 complete renal transplant-pairs with replication in 5866 complete pairs. We studied deceased-donor grafts allocated on the basis of preferential HLA matching, which provided some control for HLA genetic effects. No strong donor or recipient genetic effects contributing to long- or short-term allograft survival were found outside the HLA region. We discuss the implications for future research and clinical application.

Cell therapeutic approaches to immunosuppression after clinical kidney transplantation.

Refinement of immunosuppressive strategies has led to further improvement of kidney graft survival in recent years. Currently, the main limitations to long-term graft survival are life-threatening side effects of immunosuppression and chronic allograft injury, emphasizing the need for innovative immunosuppressive regimens that resolve this therapeutic dilemma. Several cell therapeutic approaches to immunosuppression and donor-specific unresponsiveness have been tested in early phase I and phase II clinical trials in kidney transplantation. The aim of this overview is to summarize current cell therapeutic approaches to immunosuppression in clinical kidney transplantation with a focus on myeloid suppressor cell therapy by mitomycin C-induced cells (MICs). MICs show great promise as a therapeutic agent to achieve the rapid and durable establishment of donor-unresponsiveness in living-donor kidney transplantation. Cell-based therapeutic approaches may eventually revolutionize immunosuppression in kidney transplantation in the near future.

Influence of Blood Pressure and Calcineurin Inhibitors on Kidney Function After Heart or Liver Transplantation.

BACKGROUND: Chronic kidney disease is common after heart or liver transplantation, with calcineurin inhibitors (CNI) considered the key contributor. A possible influence of posttransplant blood pressure has not been extensively examined. METHODS: Data from adult recipients of a first heart or liver transplant were analyzed regarding the relationship between blood pressure at year 1, renal function at year 5, and CNI therapy. RESULTS: Although we confirmed the well-known detrimental effect of increased 1-year systolic blood pressure on 5-year kidney graft survival, heart or liver graft survival was not affected. However, among 2534 heart transplant recipients with good renal function at year 1, increasing systolic blood pressure at year 1 was associated with higher rates of poor renal function at year 5 posttransplant. This association was confirmed on multivariate analysis overall (odds ratio, 1.25 per 20 mm Hg increment; P < 0.001) and within subgroups. Similar results were observed in 1822 liver transplant recipients (odds ratio, 1.35; P < 0.001). Neither the type of CNI nor CNI dose or trough level at year 1 showed a significant association with kidney function at year 5. CONCLUSIONS: One-year blood pressure was identified as the major modifiable risk factor associated with deteriorating kidney function between years 1 and 5 after heart or liver transplantation.