G. Tisone

Multiparameter immune profiling of operational tolerance in liver transplantation

Immunosuppressive drugs can be completely withdrawn in up to 20% of liver transplant recipients, commonly referred to as ‘operationally’ tolerant. Immune characterization of these patients, however, has not been performed in detail, and we lack tests capable of identifying tolerant patients among recipients receiving maintenance immunosuppression. In the current study we have analyzed a variety of biological traits in peripheral blood of operationally tolerant liver recipients in an attempt to define a multiparameter ‘fingerprint’ of tolerance. Thus, we have performed peripheral blood gene expression profiling and extensive blood cell immunophenotyping on 16 operationally tolerant liver recipients, 16 recipients requiring on‐going immunosuppressive therapy, and 10 healthy individuals. Microarray profiling identified a gene expression signature that could discriminate tolerant recipients from immunosuppression‐dependent patients with high accuracy. This signature included genes encoding for γδ T‐cell and NK receptors, and for proteins involved in cell proliferation arrest. In addition, tolerant recipients exhibited significantly greater numbers of circulating potentially regulatory T‐cell subsets (CD4+CD25+ T‐cells and Vδ1+ T cells) than either non‐tolerant patients or healthy individuals. Our data provide novel mechanistic insight on liver allograft operational tolerance, and constitute a first step in the search for a non‐invasive diagnostic signature capable of predicting tolerance before undergoing drug weaning.

Using transcriptional profiling to develop a diagnostic test of operational tolerance in liver transplant recipients

A fraction of liver transplant recipients are able to discontinue all immunosuppressive therapies without rejecting their grafts and are said to be operationally tolerant to the transplant. However, accurate identification of these recipients remains a challenge. To design a clinically applicable molecular test of operational tolerance in liver transplantation, we studied transcriptional patterns in the peripheral blood of 80 liver transplant recipients and 16 nontransplanted healthy individuals by employing oligonucleotide microarrays and quantitative real-time PCR. This resulted in the discovery and validation of several gene signatures comprising a modest number of genes capable of identifying tolerant and nontolerant recipients with high accuracy. Multiple peripheral blood lymphocyte subsets contributed to the tolerance-associated transcriptional patterns, although NK and gammadeltaTCR+ T cells exerted the predominant influence. These data suggest that transcriptional profiling of peripheral blood can be employed to identify liver transplant recipients who can discontinue immunosuppressive therapy and that innate immune cells are likely to play a major role in the maintenance of operational tolerance in liver transplantation.

Prospective multicenter clinical trial of immunosuppressive drug withdrawal in stable adult liver transplant recipients

Lifelong immunosuppression increases morbidity and mortality in liver transplantation. Discontinuation of immunosuppressive drugs could lessen this burden, but the safety, applicability, and clinical outcomes of this strategy need to be carefully defined. We enrolled 102 stable liver recipients at least 3 years after transplantation in a single‐arm multicenter immunosuppression withdrawal trial. Drugs were gradually discontinued over a 6 to 9‐month period. The primary endpoint was the development of operational tolerance, defined as successful immunosuppressive drug cessation maintained for at least 12 months with stable graft function and no histopathologic evidence of rejection. Out of the 98 recipients evaluated, 57 rejected and 41 successfully discontinued all immunosuppressive drugs. In nontolerant recipients rejection episodes were mild and resolved over 5.6 months (two nontolerant patients still exhibited mild gradually improving cholestasis at the end of follow‐up). In tolerant recipients no progressive clinically significant histological damage was apparent in follow‐up protocol biopsies performed up to 3 years following drug withdrawal. Tolerance was independently associated with time since transplantation (odds ratio [OR] 1.353; P = 0.0001), recipient age (OR 1.073; P = 0.009), and male gender (OR 4.657; P = 0.016). A predictive model incorporating the first two clinical variables identified subgroups of recipients with very high (79%), intermediate (30%‐38%), and very low (0%) likelihood of successful withdrawal. Conclusion: When conducted at late timepoints after transplantation, immunosuppression withdrawal is successful in a high proportion of carefully selected liver recipients. A combination of clinical parameters could be useful to predict the success of this strategy. Additional prospective studies are now needed to confirm these results and to validate clinically applicable diagnostic biomarkers. (Hepatology 2013;58:1824–1835)

Intra-graft expression of genes involved in iron homeostasis predicts the development of operational tolerance in human liver transplantation.

Following organ transplantation, lifelong immunosuppressive therapy is required to prevent the host immune system from destroying the allograft. This can cause severe side effects and increased recipient morbidity and mortality. Complete cessation of immunosuppressive drugs has been successfully accomplished in selected transplant recipients, providing proof of principle that operational allograft tolerance is attainable in clinical transplantation. The intra-graft molecular pathways associated with successful drug withdrawal, however, are not well defined. In this study, we analyzed sequential blood and liver tissue samples collected from liver transplant recipients enrolled in a prospective multicenter immunosuppressive drug withdrawal clinical trial. Before initiation of drug withdrawal, operationally tolerant and non-tolerant recipients differed in the intra-graft expression of genes involved in the regulation of iron homeostasis. Furthermore, as compared with non-tolerant recipients, operationally tolerant patients exhibited higher serum levels of hepcidin and ferritin and increased hepatocyte iron deposition. Finally, liver tissue gene expression measurements accurately predicted the outcome of immunosuppressive withdrawal in an independent set of patients. These results point to a critical role for iron metabolism in the regulation of intra-graft alloimmune responses in humans and provide a set of biomarkers to conduct drug-weaning trials in liver transplantation.

A pilot study on the safety and effectiveness of immunosuppression without prednisone after liver transplantation

BACKGROUND Corticosteroids are commonly used in the immunosuppression therapy after liver transplantation, yet are associated with considerable side effects. Retrospective studies have shown that corticosteroids can be safely withdrawn from months to years after transplant. We prospectively investigated the effects of early immunosuppression without the use of corticosteroids on graft outcome and transplant complications. METHODS Forty-five patients undergoing liver transplantation were randomized to receive immunosuppression composed of cyclosporine microemulsion and azathioprine with (n=22) or without prednisone (n=23), in conventional doses. In those patients who received prednisone, this was withdrawn within 3 months after transplant. The median follow-up of survivors was 14 months (range: 6-24). The study end points were to determine graft survival and function, infectious complications, including hepatitis C virus (HCV)-RNA levels in HCV-infected recipients, acute rejection, kidney function, and metabolic complications. RESULTS Eleven deaths occurred, 6 of which were in the prednisone group. Two-year survival did not differ between patients treated with or without prednisone (70.2% vs. 78.3%, P=0.83), nor did the causes of death. No differences were observed with regard to graft function, renal function, and infectious complications. In the subset of patients who received transplants for HCV-related cirrhosis, the dynamics of virus replication HCV-RNA was faster among those treated with prednisone. The incidence and severity of acute rejection was similar in the two groups. More than 80% of acute rejections in both groups were classified as mild or moderate and underwent spontaneous resolution. Only two patients in each group had severe acute rejection requiring additional treatment with high-dose steroids. Patients receiving prednisone tended to have greater biochemical signs of cholestasis, higher serum cholesterol and glucose levels, and more frequent insulin requirement than those treated without corticosteroids. CONCLUSIONS Liver transplantation can be performed safely without using corticosteroids in the early postoperative course, and there is no need for routine aggressive steroid treatment of established acute rejections.

Everolimus with very low-exposure cyclosporine a in de novo kidney transplantation: a multicenter, randomized, controlled trial.

Background. In combination with everolimus (EVL), cyclosporine A (CsA) may be used at low exposure, so reducing the risk of renal dysfunction in renal transplant recipients (RTR). We evaluated whether higher exposure of EVL could allow a further reduction of CsA. Methods. De novo RTR were randomized to standard exposure EVL (C0 3–8 ng/mL) with low-concentration CsA (C2 maintenance levels 350–500 ng/mL, group A) or higher EVL exposure (C0 8–12 ng/mL) with very low-concentration CsA (C2 maintenance levels 150–300 ng/mL, group B). The primary endpoints were 6-month creatinine clearance (CrCl) and biopsy-proven acute rejection (BPAR) rate. After 6 months, patients were followed up (observational extension) to 12 months. Results. Two hundred eighty-five RTR (97% from deceased donors) were enrolled. Two patients per group died (1.4%). The 6-month death-censored graft survival was 90.2% in group A and 97.9% in group B and was unchanged at 12 months (P=0.007). There was no significant difference between groups at 6 months in CrCl (59.9 vs. 57.8 mL/min) and BPAR rates (14.7% vs. 11.9%) and also at 12 months (CrCl 62.5±20.7 vs. 61.3±22.0 mL/min, BPAR 14.7% vs. 14.1%). No significant differences were seen in treated acute rejections, steroid-resistant acute rejections, treatment failures, or delayed graft function, although there was a trend to better results in group B. Conclusions. EVL given at higher exposure for 6 months plus very low CsA concentration may obtain low acute rejection rate and good graft survival in De novo renal transplantation. However, there was no difference between groups in CrCl.

Alpha-fetoprotein and modified response evaluation criteria in Solid Tumors progression after locoregional therapy as predictors of hepatocellular cancer recurrence and death after transplantation.

Locoregional therapy (LRT) is being increasingly used for the management of hepatocellular cancer (HCC) in patients listed for liver transplantation (LT). Although several selection criteria have been developed, stratifications of survival according to the pathology of explanted livers and pre‐LT LRT are lacking. Radiological progression according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST) and alpha‐fetoprotein (AFP) behavior was reviewed for 306 patients within the Milan criteria (MC‐IN) and 116 patients outside the Milan criteria (MC‐OUT) who underwent LRT and LT between January 1999 and March 2010. A prospectively collected database originating from 6 collaborating European centers was used for the study. Sixty‐one patients (14.5%) developed HCC recurrence. For both MC‐IN and MC‐OUT patients, an AFP slope > 15 ng/mL/month and mRECIST progression were unique independent risk factors for HCC recurrence and patient death. When the radiological Milan criteria (MC) status was combined with radiological and biological progression, MC‐IN and MC‐OUT patients without risk factors had similarly excellent 5‐year tumor‐free and patient survival rates. MC‐IN patients with at least 1 risk factor had worse outcomes, and MC‐OUT patients with at least 1 risk factor had the poorest survival (P < 0.001). In conclusion, both radiological and biological modifications permit documentation of the response to LRT in patients waiting for LT. According to these 2 parameters, tumor progression significantly increases the risk of recurrence and patient death not only for MC‐OUT patients but also for MC‐IN patients. The monitoring of both parameters in combination with the initial radiological MC status is an essential element for further refining the selection criteria for potential liver recipients with HCC. Liver Transpl 19:1108‐1118, 2013.

Balancing Donor and Recipient Risk Factors in Liver Transplantation: The Value of D‐MELD With Particular Reference to HCV Recipients

Donor–recipient match is a matter of debate in liver transplantation. D‐MELD (donor age × recipient biochemical model for end‐stage liver disease [MELD]) and other factors were analyzed on a national Italian database recording 5946 liver transplants. Primary endpoint was to determine factors predictive of 3‐year patient survival. D‐MELD cutoff predictive of 5‐year patient survival <50% (5yrsPS<50%) was investigated. A prognosis calculator was implemented (http://www.D‐MELD.com). Differences among D‐MELD deciles allowed their regrouping into three D‐MELD classes (A < 338, B 338–1628, C >1628). At 3 years, the odds ratio (OR) for death was 2.03 (95% confidence interval [CI], 1.44–2.85) in D‐MELD class C versus B. The OR was 0.40 (95% CI, 0.24–0.66) in class A versus class B. Other predictors were hepatitis C virus (HCV; OR = 1.42; 95% CI, 1.11–1.81), hepatitis B virus (HBV; OR = 0.69; 95% CI, 0.51–0.93), retransplant (OR = 1.82; 95% CI, 1.16–2.87) and low‐volume center (OR = 1.48; 95% CI, 1.11–1.99). Cox regressions up to 90 months confirmed results. The hazard ratio was 1.97 (95% CI, 1.59–2.43) for D‐MELD class C versus class B and 0.42 (95% CI, 0.29–0.60) for D‐MELD class A versus class B. Recipient age, HCV, HBV and retransplant were also significant. The 5yrsPS<50% cutoff was identified only in HCV patients (D‐MELD ≥ 1750). The innovative approach offered by D‐MELD and covariates is helpful in predicting outcome after liver transplantation, especially in HCV recipients.

Switch to 1.5 grams MMF monotherapy for CNI-related toxicity in liver transplantation is safe and improves renal function, dyslipidemia, and hypertension

Although mycophenolate mofetil (MMF) monotherapy has been successfully used in liver transplant recipients suffering from calcineurin‐inhibitor (CNI)‐related chronic toxicity, still no consensus has been reached on its safety, efficacy and tolerability. We attempted the complete weaning off CNI in 42 individuals presenting chronic renal dysfunction and/or dyslipidemia and/or arterial hypertension and simultaneously introduced 1.5 gm/day MMF. CNI could be completely withdrawn in 41 cases. A total of 32 (75%) patients are currently on ≤1.5 gm/day of MMF. Mean follow‐up from the introduction of MMF is 31.5 months and mean length of follow‐up from the beginning of MMF monotherapy is 27.3 months. Renal function improved in 31/36 (89%) cases. Blood levels of cholesterol and triglycerides decreased in 13 of 17 (76%) and 15 of 17 (89%) patients, respectively. Arterial hypertension improved in 4 of 5 (80%) cases. A total of 8 patients showed a single episode of fluctuation of liver function tests during tapering off CNI. This feature was interpreted as an acute rejection (AR), based on the resolution of the clinical setting after escalation of MMF daily dose to 2 gm. A further patient developed a biopsy‐proven AR insensitive to MMF adjustment, requiring reinstitution of the CNI dose. No deaths or major toxicity requiring MMF discontinuation occurred. In conclusion, low dose MMF monotherapy is safe, effective, and well tolerated. Liver Transpl, 2007.

2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody‐mediated liver allograft rejection at the 11th (Paris, France, June 5–10, 2011), 12th (Comandatuba, Brazil, August 19–23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5–10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody‐mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.