KLRG1+ NK cells protect T-bet-deficient mice from pulmonary metastatic colorectal carcinoma.

We studied the developmental and functional mechanisms behind NK cell-mediated antitumor responses against metastatic colorectal carcinoma (CRC) in mice. In particular, we focused on investigating the significance of T-box transcription factors and the immunotherapeutic relevance of IL-15 in the development and function of tumor-reactive NK cells. Pulmonary CRC metastases were experimentally seeded via an adoptive i.v. transfer of luciferase-expressing CT26 CRC cells that form viewable masses via an in vivo imaging device; genetically deficient mice were used to dissect the antitumor effects of developmentally different NK cell subsets. IL-15 precomplexed to IL-15 receptor-α was used in immunotherapy experiments. We found that mice deficient for the T-box transcription factor T-bet lack terminally differentiated antitumor CD27(low)KLRG1(+) NK cells, leading to a terminal course of rapid-onset pulmonary CRC metastases. The importance of this NK cell subset for effective antitumor immunity was shown by adoptively transferring purified CD27(low)KLRG1(+) NK cells into T-bet-deficient mice and, thereby, restoring immunity against lung metastasis formation. Importantly, immunity to metastasis formation could also be restored in T-bet-deficient recipients by treating mice with IL-15 precomplexed to IL-15 receptor-α, which induced the development of eomesodermin(+)KLRG1(+) NK cells from existing NK cell populations. Thus, contingent upon their T-bet-dependent development and activation status, NK cells can control metastatic CRC in mice, which is highly relevant for the development of immunotherapeutic approaches in the clinic.

Morbidity of hepatic resection for intermediate and advanced hepatocellular carcinoma.

PURPOSE: According to current treatment guidelines, surgical resection of hepatocellular carcinoma (HCC) is mostly restricted to a limited subgroup of patients. Due to improved surgical techniques and perioperative management, liver resections may also be performed more extendedly and also in cirrhotic livers with clinical signs of portal hypertension in selected patients. In this study, the clinical and long-term outcomes of liver resection in HCC patients with or without liver cirrhosis were evaluated. METHODS: One hundred fifty-eight patients undergoing liver resection for primary HCC at our institution were identified. Logistic and Cox regression analyses were used to identify prognostic parameters for postoperative complications and survival. RESULTS: In our cohort of patients, there was no association between clinical parameters or extent of surgical resection and postoperative morbidity. Only Barcelona Clinic Liver Cancer (BCLC) stage C patients were at significantly higher risk for major complications (OR 5.27, P = 0.009). Risk factors influencing long-term survival were patient age (HR 1.026, P = 0.027) and BCLC stage C (HR 3.47, P = 0.002). Compared to patients without liver cirrhosis, BCLC stage A and B patients undergoing resection were at similar risk for the development of severe complications and long-term mortality. CONCLUSION: Liver resection as potentially curative therapy can be performed in selected patients in BCLC stage B, as well as in patients with clinical signs of portal hypertension. The resection of HCC-classified BCLC stage C is feasible but associated with significant morbidity and mortality.

Double deficiency for RORγt and T-bet drives Th2-mediated allograft rejection in mice.

Although Th1, Th2, and Th17 cells are thought to be major effector cells in adaptive alloimmune responses, their respective contribution to allograft rejection remains unclear. To precisely address this, we used mice genetically modified for the Th1 and Th17 hallmark transcription factors T-bet and RORγt, respectively, which allowed us to study the alloreactive role of each subset in an experimental transplant setting. We found that in a fully mismatched heterotopic mouse heart transplantation model, T cells deficient for T-bet (prone to Th17 differentiation) versus RORγt (prone to Th1 differentiation) rejected allografts at a more accelerated rate, indicating a predominance of Th17- over Th1-driven alloimmunity. Importantly, T cells doubly deficient for both T-bet and RORγt differentiated into alloreactive GATA-3-expressing Th2 cells, which promptly induced allograft rejection characterized by a Th2-type intragraft expression profile and eosinophilic infiltration. Mechanistically, Th2-mediated allograft rejection was contingent on IL-4, as its neutralization significantly prolonged allograft survival by reducing intragraft expression of Th2 effector molecules and eosinophilic allograft infiltration. Moreover, under IL-4 neutralizing conditions, alloreactive double-deficient T cells upregulated Eomesodermin (Eomes) and IFN-γ, but not GATA-3. Thus, in the absence of T-bet and RORγt, Eomes may salvage Th1-mediated alloimmunity that underlies IL-4 neutralization-resistant allograft rejection. We summarize that, whereas Th17 cells predictably promote allograft rejection, IL-4-producing GATA-3(+) Th2 cells, which are generally thought to protect allogeneic transplants, may actually be potent facilitators of organ transplant rejection in the absence of T-bet and RORγt. Moreover, Eomes may rescue Th1-mediated allograft rejection in the absence of IL-4, T-bet, and RORγt.

Unconventional RORγt+ T cells drive hepatic ischemia reperfusion injury.

An emerging body of evidence suggests a pivotal role of CD3(+) T cells in mediating early ischemia reperfusion injury (IRI). However, the precise phenotype of T cells involved and the mechanisms underlying such T cell-mediated immune responses in IRI, as well as their clinical relevance, are poorly understood. In this study, we investigated early immunological events in a model of partial warm hepatic IRI in genetically targeted mice to study the precise pathomechanistic role of RORγt(+) T cells. We found that unconventional CD27(-)γδTCR(+) and CD4(-)CD8(-) double-negative T cells are the major RORγt-expressing effector cells in hepatic IRI that play a mechanistic role by being the main source of IRI-mediating IL-17A. We further show that unconventional IRI-mediating T cells are contingent on RORγt, as highlighted by the fact that a genetic deficiency for RORγt, or its therapeutic antagonization via digoxin, is protective against hepatic IRI. Therefore, identification of CD27(-)γδTCR(+) and CD4(-)CD8(-) double-negative T cells as the major source of IL-17A via RORγt in hepatic IRI opens new therapeutic options to improve liver transplantation outcomes.

Neuroendocrine tumors of the pancreas: a retrospective single-center analysis using the ENETS TNM-classification and immunohistochemical markers for risk stratification.

BACKGROUND: This study was performed to assess the 2006 introduced ENETS TNM-classification with respect to patient survival and surgical approach for patients who underwent surgery for a neuroendocrine tumor of the pancreas (PNET). METHODS: Between 2001 and 2010 38 patients after resection of a PNET were investigated regarding tumor localization and size. Further, patient survival with regards to the new TNM-classification, the operation methods and immunohistochemical markers was analyzed. RESULTS: The estimated mean survival time of the 38 patients was 91 ± 10 months (female 116 ± 9, male 56 ± 14 months; p = 0.008). The 5-year survival rate was 63.9%. Patient survival differed significantly depending on tumor size (pT1 107 ± 13, pT2 94 ± 16, pT3 44 ± 7 and pT4 18 ± 14 months; P = 0.006). Patients without lymph node metastasis survived significantly longer compared to patients with positive lymph node status (108 ± 9 vs. 19 ± 5 months; P < 0.001). However, survival in patients with and without distant metastasis did not differ significantly (92 ± 11 vs. 80 ± 23 months; P = 0.876). Further, the tumor grading significantly influenced patient survival (G1 111 ± 12, G2 68 ± 12 and G3 21 ± 14 months; P = 0.037). CONCLUSIONS: As part of the TNM-classification especially lymph node status and also tumor size and grading were identified as important factors determining patient survival. Further, gender was demonstrated to significantly influence survival time. If an R0 resection was achieved in patients with distant metastases patient survival was comparable to patients without metastasis.

Bile duct damage after cold storage of deceased donor livers predicts biliary complications after liver transplantation.

BACKGROUND & AIMS: The aim of this study was to examine the development of biliary epithelial damage between organ retrieval and transplantation and its clinical relevance for patients. METHODS: Common bile duct samples during donor hepatectomy, after cold storage, and after reperfusion were compared to healthy controls by hematoxylin and eosin (H&E) staining and immunofluorescence for tight junction protein 1 and Claudin-1. A bile duct damage score to quantify biliary epithelial injury was developed and correlated with recipient and donor data and patient outcome. RESULTS: Control (N=16) and donor hepatectomy bile ducts (N=10) showed regular epithelial morphology and tight junction architecture. After cold storage (N=37; p=0.0119), and even more after reperfusion (N=62; p=0.0002), epithelial damage, as quantified by the bile duct damage score, was markedly increased, and both tight junction proteins were detected with inappropriate morphology. Patients with major bile duct damage after cold storage had a significantly increased risk of biliary complications (relative risk 18.75; p<0.0001) and graft loss (p=0.0004). CONCLUSIONS: In many cases, the common bile duct epithelium shows considerable damage after cold ischemia with further damage occurring after reperfusion. The extent of epithelial damage can be quantified by our newly developed bile duct damage score and is a prognostic parameter for biliary complications and graft loss. Possibly, in an intraoperative histological examination, this bile duct damage score may influence decision-making in transplantation surgery.

Right portal vein ligation combined with in situ splitting induces rapid left lateral liver lobe hypertrophy enabling 2-staged extended right hepatic resection in small-for-size settings.

OBJECTIVE: To evaluate a new 2-step technique for obtaining adequate but short-term parenchymal hypertrophy in oncologic patients requiring extended right hepatic resection with limited functional reserve. BACKGROUND: Patients presenting with primary or metastatic liver tumors often face the dilemma that the remaining liver tissue may not be sufficient. Preoperative portal vein embolization has thus far been established as the standard procedure for achieving resectability. METHODS: Two-staged hepatectomy was performed in patients who preoperatively appeared to be marginally resectable but had a tumor-free left lateral lobe. Marginal respectability was defined as a left lateral lobe to body weight ratio of less than 0.5. In the first step, surgical exploration, right portal vein ligation (PVL), and in situ splitting (ISS) of the liver parenchyma along the falciform ligament were performed. Computed tomographic volumetry was performed before ISS and before completion surgery. RESULTS: The study included 25 patients with primary liver tumors (hepatocellular carcinoma: n = 3, intrahepatic cholangiocarcinoma: n = 2, extrahepatic cholangiocarcinoma: n = 2, malignant epithelioid hemangioendothelioma: n = 1, gallbladder cancer: n = 1 or metastatic disease [colorectal liver metastasis]: n = 14, ovarian cancer: n = 1, gastric cancer: n = 1). Preoperative CT volumetry of the left lateral lobe showed 310 mL in median (range = 197-444 mL). After a median waiting period of 9 days (range = 5-28 days), the volume of the left lateral lobe had increased to 536 mL (range = 273-881 mL), representing a median volume increase of 74% (range = 21%-192%) (P < 0.001). The median left lateral liver lobe to body weight ratio was increased from 0.38% (range = 0.25%-0.49%) to 0.61% (range = 0.35-0.95). Ten of 25 patients (40%) required biliary reconstruction with hepaticojejunostomy. Rapid perioperative recovery was reflected by normalization of International normalized ratio (INR) (80% of patients), creatinine (84% of patients), nearly normal bilirubin (56% of patients), and albumin (64% of patients) values by day 14 after completion surgery. Perioperative morbidity was classified according to the Dindo-Clavien classification of surgical complications: grade I (12 events), grade II (13 events), grade III (14 events, III a: 6 events, III b: 8 events), grade IV (8 events, IV a: 3 events, IV b: 5 events), and grade V (3 events). Sixteen patients (68%) experienced perioperative complications. Follow-up was 180 days in median (range: 60-776 days) with an estimated overall survival of 86% at 6 months after resection. CONCLUSIONS: Two-step hepatic resection performing surgical exploration, PVL, and ISS results in a marked and rapid hypertrophy of functional liver tissue and enables curative resection of marginally resectable liver tumors or metastases in patients that might otherwise be regarded as palliative.

DX5+NKT cells display phenotypical and functional differences between spleen and liver as well as NK1.1-Balb/c and NK1.1+ C57Bl/6 mice.

BACKGROUND: Natural killer T cells represent a linkage between innate and adaptive immunity. They are a heterogeneous population of specialized T lymphocytes composed of different subsets. DX5+NKT cells are characterized by expression of the NK cell marker DX5 in the context of CD3. However, little is known about the phenotype and functional capacity of this unique cell population. Therefore, we investigated the expression of several T cell and NK cell markers, as well as functional parameters in spleen and liver subsets of DX5+NKT cells in NK1.1- Balb/c mice and compared our findings to NK1.1+ C57Bl/6 mice. RESULTS: In the spleen 34% of DX5+NKT cells expressed CD62L and they up-regulated the functional receptors CD154 as well as CD178 upon activation. In contrast, only a few liver DX5+NKT cells expressed CD62L, and they did not up-regulate CD154 upon activation. A further difference between spleen and liver subsets was observed in cytokine production. Spleen DX5+NKT cells produced more Th1 cytokines including IL-2, IFN-γ and TNF-α, while liver DX5+NKT cells secreted more Th2 cytokines (e.g. IL-4) and even the Th17 cytokine, IL-17a. Furthermore, we found inter-strain differences. In NK1.1+ C57Bl/6 mice DX5+NKT cells represented a distinct T cell population expressing less CD4 and more CD8. Accordingly, these cells showed a CD178 and Th2-type functional capacity upon activation. CONCLUSION: These results show that DX5+NKT cells are a heterogeneous population, depending on the dedicated organ and mouse strain, that has diverse functional capacity.

Study protocol: a pilot study to determine the safety and efficacy of induction-therapy, de novo MPA and delayed mTOR-inhibition in liver transplant recipients with impaired renal function. PATRON-study.

BACKGROUND: Patients undergoing liver transplantation with preexisting renal dysfunction are prone to further renal impairment with the early postoperative use of Calcineurin-inhibitors. However, there is only little scientific evidence for the safety and efficacy of de novo CNI free "bottom-up" regimens in patients with impaired renal function undergoing liver transplantation. This is a single-center study pilot-study (PATRON07) investigating safety and efficacy of CNI-free, "bottom-up" immunosuppressive (IS) strategy in patients undergoing liver transplantation (LT) with renal impairment prior to LT. METHODS/DESIGN: Patients older than 18 years with renal impairment at the time of liver transplantation eGFR < 50 ml/min and/or serum creatinine levels > 1.5 mg/dL will be included. Patients in will receive a CNI-free combination therapy (basiliximab, MMF, steroids and delayed Sirolimus). Primary endpoint is the incidence of steroid resistant acute rejection within the first 30 days after LT. The study is designed as prospective two-step trial requiring a maximum of 29 patients. In the first step, 9 patients will be included. If 8 or more patients show no signs of biopsy proven steroid resistant rejection, additional 20 patients will be included. If in the second step a total of 27 or more patients reach the primary endpoint the regimen is regarded to be safe and efficient. DISCUSSION: If a CNI-free-"bottom-up" IS strategy is safe and effective, this may be an innovative concept in contrast to classic top-down strategies that could improve the patient short and long-time renal function as well as overall complications and survival after LT. The results of PATRON07 may be the basis for a large multicenter RCT investigating the new "bottom-up" immunosuppressive strategy in patients with poor renal function prior to LT.http://www.clinicaltrials.gov-identifier: NCT00604357.

Improved outcome after 'bottom-up' immunosuppression in liver transplant recipients with preoperative renal impairment.

BACKGROUND: Most patients with high MELD scores have impaired renal function prior to transplantation. PATIENT AND METHODS: A retrospective case control study was conducted with initial low immunosuppression, which was increased when patients rejected or were clinically stable beyond day 30 ('bottom-up'). RESULTS: Thirty patients with impaired renal function were included. Fifteen were treated with de novo cyclosporine A (CsA; group A), and 15 had 'bottom-up' immunosuppression (group B). Baseline renal function was similar: serum creatinine (SCr) median 1.8 mg/dl (range: 1.5-4.0 mg/dl; group A) versus 2.4 mg/dl (range: 1.5-4.0 mg/dl; group B; p = 0.24). The requirement for renal replacement therapy was significantly lower in group B (p = 0.032). Ten received 'bottom-up' immunosuppression [4 CsA/1 sirolimus (Sir) 'on demand' after rejection, 5 Sir (stable)] beyond day 30. By months 6 and 12 (1.6 mg/dl vs. 1.2 mg/dl), SCr values were significantly better in group B (p = 0.006). Renal function in group B did not differ between patients receiving CsA or Sir. Overall complication rates, survival and biopsy-proven acute rejection were similar, although BANFF scores were higher in group B (p = 0.004). CONCLUSION: Successful implementation of 'bottom-up' immunosuppression in liver transplant recipients with high lab-MELD scores and renal dysfunction at the time of transplantation has the potential to substantially improve short- and long-term outcomes.

Murine DX5+NKT Cells Display Their Cytotoxic and Proapoptotic Potentials against Colitis-Inducing CD4+CD62Lhigh T Cells through Fas Ligand.

INTRODUCTION: It has been previously shown that immunoregulatory DX5+NKT cells are able to prevent colitis induced by CD4+CD62Lhigh T lymphocytes in a SCID mouse model. The aim of this study was to further investigate the underlying mechanism in vitro. METHODS: CD4+CD62Lhigh and DX5+NKT cells from the spleen of Balb/c mice were isolated first by MACS, followed by FACS sorting and cocultured for up to 96 h. After polyclonal stimulation with anti-CD3, anti-CD28, and IL-2, proliferation of CD4+CD62Lhigh cells was assessed using a CFSE assay and activity of proapoptotic caspase-3 was determined by intracellular staining and flow cytometry. Extrinsic apoptotic pathway was blocked using an unconjugated antibody against FasL, and activation of caspase-3 was measured. RESULTS: As previously shown in vivo, DX5+NKT cells inhibit proliferation of CD4+CD62Lhigh cells in vitro after 96 h coculture compared to a CD4+CD62Lhigh monoculture (proliferation index: 1.39 ± 0.07 vs. 1.76 ± 0.12; P = 0.0079). The antiproliferative effect of DX5+NKT cells was likely due to an induction of apoptosis in CD4+CD62Lhigh cells as evidenced by increased activation of the proapoptotic caspase-3 after 48 h (38 ± 3% vs. 28 ± 3%; P = 0.0451). Furthermore, DX5+NKT cells after polyclonal stimulation showed an upregulation of FasL on their cell surface (15 ± 2% vs. 2 ± 1%; P = 0.0286). Finally, FasL was blocked on DX5+NKT cells, and therefore, the extrinsic apoptotic pathway abrogated the activation of caspase-3 in CD4+CD62Lhigh cells. CONCLUSION: Collectively, these data confirmed that DX5+NKT cells inhibit proliferation of colitis-inducing CD4+CD62Lhigh cells by induction of apoptosis. Furthermore, DX5+NKT cells likely mediate their cytotoxic and proapoptotic potentials via FasL, confirming recent reports about iNKT cells. Further studies will be necessary to evaluate the therapeutical potential of these immunoregulatory cells in patients with colitis.

Extended Pancreas Donor Program-The EXPAND Study: A Prospective Multicenter Trial Testing the Use of Pancreas Donors Older Than 50 Years.

BACKGROUND: Pancreas transplantation is the only curative treatment option for patients with juvenile diabetes. Organ shortage and restrictive allocation criteria are the main reasons for increasing waitlists, leading to severe morbidity and mortality. We designed a study to increase the donor pool with extended donor criteria (EDC) organs (donor age, 50-60 years; body mass index, 30-34 kg/m). METHODS: Utilization of EDC organs required the implementation of a new allocation system within Eurotransplant. The study was a prospective, multicenter, 2-armed trial. The primary endpoint was pancreas function after 3 months. Rejection episodes, kidney function, and waitlist time were secondary endpoints. Patients receiving an EDC organ were study group patients; recipients of standard organs were control group patients. Follow-up was 1 year. RESULTS: Seventy-nine patients were included in 12 German centers, 18 received EDC organs and 61 received standard organs. Recipient demographics were similar. Mean EDC donor age was 51.4 ± 5 years versus 31.7 ± 12 in the control group. Insulin-free graft survival was 83.3% for EDC and 67.2% for standard organs (P = 0.245) after 3 months. One-year pancreas survival was 83.3% and 83.5% in the EDC versus standard group. One-year kidney allograft survival was approximately 94% in both groups. Rejection episodes and morbidity were similar. CONCLUSIONS: The Extended Pancreas Donor Program (EXPAND) shows in a prospective trial that selected EDC organs of donors older than 50 years can be used with outcomes similar to standard-criteria organs, therefore showing potential to reduce organ shortage and waiting times. This study substantiates the full implementation of EDC organs in a pancreas allocation system.

Extended pancreas donor program - the EXPAND study rationale and study protocol.

BACKGROUND: Simultaneous pancreas kidney transplantation (SPK), pancreas transplantation alone (PTA) or pancreas transplantation after kidney (PAK) are the only curative treatment options for patients with type 1 (juvenile) diabetes mellitus with or without impaired renal function. Unfortunately, transplant waiting lists for this indication are increasing because the current organ acceptability criteria are restrictive; morbidity and mortality significantly increase with time on the waitlist. Currently, only pancreas organs from donors younger than 50 years of age and with a body mass index (BMI) less than 30 are allocated for transplantation in the Eurotransplant (ET) area. To address this issue we designed a study to increase the available donor pool for these patients. METHODS/DESIGN: This study is a prospective, multicenter (20 German centers), single blinded, non-randomized, two armed trial comparing outcome after SPK, PTA or PAK between organs with the currently allowed donor criteria versus selected organs from donors with extended criteria. Extended donor criteria are defined as organs procured from donors with a BMI of 30 to 34 or a donor age between 50 and 60 years. Immunosuppression is generally standardized using induction therapy with Myfortic, tacrolimus and low dose steroids. In principle, all patients on the waitlist for primary SPK, PTA or PAK are eligible for the clinical trial when they consent to possibly receiving an extended donor criteria organ. Patients receiving an organ meeting the current standard criteria for pancreas allocation (control arm) are compared to those receiving extended criteria organ (study arm); patients are blinded for a follow-up period of one year. The combined primary endpoint is survival of the pancreas allograft and pancreas allograft function after three months, as an early relevant outcome parameter for pancreas transplantation. DISCUSSION: The EXPAND Study has been initiated to investigate the hypothesis that locally allocated extended criteria organs can be transplanted with similar results compared to the currently allowed standard ET organ allocation. If our study shows a favorable comparison to standard organ allocation criteria, the morbidity and mortality for patients waiting for transplantation could be reduced in the future. TRIAL REGISTRATION: Trial registered at: NCT01384006.

Distribution of intrahepatic T, NK and CD3(+)CD56(+)NKT cells alters after liver transplantation: Shift from innate to adaptive immunity?

BACKGROUND: The liver is an immunological organ containing a large number of T, NK and NKT cells, but little is known about intrahepatic immunity after LTx. Here, we investigated whether the distribution of T, NK and CD3(+)CD56(+)NKT cells is altered in transplanted livers under different circumstances. METHODS: Core biopsies of transplanted livers were stained with antibodies against CD3 and CD56. Several cell populations including T (CD3(+)CD56(-)), NK (CD3(-)CD56(+)) and NKT cells (CD3(+)CD56(+)) were studied by fluorescence microscopy. Cell numbers were analyzed in relation to the time interval after LTx, immunosuppressive therapy and stage of acute graft rejection (measured with the rejection activity index: RAI) compared to tumor free liver tissue from patients after liver resection due to metastatic disease as control. RESULTS: Recruitment of CD3(+)CD56(+)NKT cells revealed a significant decrease during high RAI scores in comparison to low and middle RAI scores (RAI 7-9: 0.03±0.01/HPF vs. RAI 4-6: 0.1±0.005/HPF). CD3(+)CD56(+)NKT cells were also lower during immunosuppressive therapy with tacrolimus (0.03±0.01/HPF) than with cyclosporine (0.1±0.003/HPF), cyclosporine/MMF (0.1±0.003/HPF) or sirolimus (0.1±0.01/HPF) treatment. Intrahepatic T cell numbers increased significantly 50days after LTx compared to control liver tissue (4.5±0.2/HPF vs. 1.9±0.1/HPF). In contrast, NK cells (0.3±0.004/HPF) were significantly fewer in all biopsies after LTx compared to the control (0.7±0.04/HPF). CONCLUSIONS: These data indicate significant alterations in the hepatic recruitment of T, NK and CD3(+)CD56(+)NKT cells after LTx. The increase in T cells and the decrease in NK and CD3(+)CD56(+)NKT cells suggest a shift from innate to adaptive hepatic immunity in the liver graft.

Calcineurin inhibitor minimization protocols in liver transplantation.

Liver transplant recipients are at increasingly high risk for suffering from impaired renal function and probable need of renal replacement therapy. Extended criteria organs and transplantation of patients with higher model for end-stage liver disease scores further increase this problem. Acute and chronic nephrotoxicity are the trade-off in immunosuppression with potent calcineurin inhibitors (CNIs). As a good renal function is associated with better graft and patient survival, CNI minimization protocols have been developed. Current strategies to overcome CNI toxicity include reduction or withdrawal of CNIs concurrently with switching over to mammalian target of rapamycin inhibitor or mycophenolate mofetil (MMF)-based regimens. This strategy caused an improvement in renal function in a significant number of liver transplantation patients according to several studies. However, total CNI avoidance seems to result in higher rejection rates. To prevent chronic renal dysfunction in patients prone to or with acute renal failure, CNI delay - with induction therapy for bridging - followed by low-dose CNI in combination with MMF are proven strategies without risking higher rejection rates. An individualized, tailor-made immunosuppressive regime, with a special focus on renal function is recommended. This review gave an overview on CNI minimization protocols in liver transplantation also focusing on recently analyzed studies.

DX5+ NKT cells induce the death of colitis-associated cells: involvement of programmed death ligand-1.

NKT cells are activated by CD1d and show an immune regulating function. Here, we investigated whether DX5+ NKT cells could be used to reduce colitis in a chronic colitis mouse model and studied the potential immunological mechanisms involved. Chronic colitis was induced either by transfer of enriched CD62L+ CD4+ T cells to severe-combined-immunodeficient mice or by feeding dextran sodium sulfate to immune competent mice. DX5+ NKT cells were transferred to mice with chronic colitis. Co-transfer of DX5+ NKT cells, but not CD8+ control cells, prevented the onset of colitis, and the immune regulatory effect of DX5+ NKT cells was completely abrogated by injecting CD1d blocking antibody. Moreover, DX5+ NKT cells reduced established colitis in both chronic colitis models. In vitro, DX5+ NKT cells induced cell death of colon-infiltrating lymphocytes isolated from diseased mice. This effect was inhibited in the presence of either anti-CD1d or anti-programmed death ligand-1 (PD-L1) blocking antibodies. The specific potency of DX5+ NKT cells in regulating chronic colitis in two mouse models is demonstrated. In vitro testing suggests that DX5+ NKT cells activated by CD1d induce cell death of colitis-inducing lymphocytes, which is mediated through PD-L1. Therefore, DX5+ NKT cells could be important in the regulation of immune responses associated with chronic colitis.