Vincent Donckier

Characterization of human DNGR-1+ BDCA3+ leukocytes as putative equivalents of mouse CD8α+ dendritic cells

In mouse, a subset of dendritic cells (DCs) known as CD8α+ DCs has emerged as an important player in the regulation of T cell responses and a promising target in vaccination strategies. However, translation into clinical protocols has been hampered by the failure to identify CD8α+ DCs in humans. Here, we characterize a population of human DCs that expresses DNGR-1 (CLEC9A) and high levels of BDCA3 and resembles mouse CD8α+ DCs in phenotype and function. We describe the presence of such cells in the spleens of humans and humanized mice and report on a protocol to generate them in vitro. Like mouse CD8α+ DCs, human DNGR-1+ BDCA3hi DCs express Necl2, CD207, BATF3, IRF8, and TLR3, but not CD11b, IRF4, TLR7, or (unlike CD8α+ DCs) TLR9. DNGR-1+ BDCA3hi DCs respond to poly I:C and agonists of TLR8, but not of TLR7, and produce interleukin (IL)-12 when given innate and T cell–derived signals. Notably, DNGR-1+ BDCA3+ DCs from in vitro cultures efficiently internalize material from dead cells and can cross-present exogenous antigens to CD8+ T cells upon treatment with poly I:C. The characterization of human DNGR-1+ BDCA3hi DCs and the ability to grow them in vitro opens the door for exploiting this subset in immunotherapy.

Early Liver Transplantation for Severe Alcoholic Hepatitis

BACKGROUND A 6-month abstinence from alcohol is usually required before patients with severe alcoholic hepatitis are considered for liver transplantation. Patients whose hepatitis is not responding to medical therapy have a 6-month survival rate of approximately 30%. Since most alcoholic hepatitis deaths occur within 2 months, early liver transplantation is attractive but controversial. METHODS We selected patients from seven centers for early liver transplantation. The patients had no prior episodes of alcoholic hepatitis and had scores of 0.45 or higher according to the Lille model (which calculates scores ranging from 0 to 1, with a score ≥ 0.45 indicating nonresponse to medical therapy and an increased risk of death in the absence of transplantation) or rapid worsening of liver function despite medical therapy. Selected patients also had supportive family members, no severe coexisting conditions, and a commitment to alcohol abstinence. Survival was compared between patients who underwent early liver transplantation and matched patients who did not. RESULTS In all, 26 patients with severe alcoholic hepatitis at high risk of death (median Lille score, 0.88) were selected and placed on the list for a liver transplant within a median of 13 days after nonresponse to medical therapy. Fewer than 2% of patients admitted for an episode of severe alcoholic hepatitis were selected. The centers used 2.9% of available grafts for this indication. The cumulative 6-month survival rate (±SE) was higher among patients who received early transplantation than among those who did not (77 ± 8% vs. 23 ± 8%, P<0.001). This benefit of early transplantation was maintained through 2 years of follow-up (hazard ratio, 6.08; P = 0.004). Three patients resumed drinking alcohol: one at 720 days, one at 740 days, and one at 1140 days after transplantation. CONCLUSIONS Early liver transplantation can improve survival in patients with a first episode of severe alcoholic hepatitis not responding to medical therapy. (Funded by Société Nationale Française de Gastroentérologie.).

Laparoscopic liver resection of benign liver tumors: Results of a multicenter European experience

Objective: The objective of this study was to assess the feasibility, safety, and outcome of laparoscopic liver resection for benign liver tumors in a multicenter setting. Background: Despite restrictive, tailored indications for resection in benign liver tumors, an increasing number of articles have been published concerning laparoscopic liver resection of these tumors. Methods: A retrospective study was performed in 18 surgical centres in Europe regarding their experience with laparoscopic resection of benign liver tumors. Detailed standardized questionnaires were used that focused on patients characteristics, clinical data, type and characteristics of the tumor, technical details of the operation, and early and late clinical outcome. Results: From March 1992 to September 2000, 87 patients suffering from benign liver tumor were included in this study: 48 patients with focal nodular hyperplasia (55%), 17 patients with liver cell adenoma (21%), 13 patients with hemangioma (15%), 3 patients with hamartoma (3%), 3 patients with hydatid liver cysts (3%), 2 patients with adult polycystic liver disease (APLD) (2%), and 1 patient with liver cystadenoma (1%). The mean size of the tumor was 6 cm, and 95% of the tumors were located in the left liver lobe or in the anterior segments of the right liver. Liver procedures included 38 wedge resections, 25 segmentectomies, 21 bisegmentectomies (including 20 left lateral segmentectomies), and 3 major hepatectomies. There were 9 conversions to an open approach (10%) due to bleeding in 45% of the patients. Five patients (6%) received autologous blood transfusion. There was no postoperative mortality, and the postoperative complication rate was low (5%). The mean postoperative hospital stay was 5 days (range, 2–13 days). At a mean follow-up of 13 months (median, 10 months; range, 2–58 months), all patients are alive without disease recurrence, except for the 2 patients with APLD. Conclusions: Laparoscopic resection of benign liver tumors is feasible and safe for selected patients with small tumors located in the left lateral segments or in the anterior segments of the right liver. Despite the use of a laparoscopic approach, selective indications for resection of benign liver tumors should remain unchanged. When performed by expert liver and laparoscopic surgeons in selected patients and tumors, laparoscopic resection of benign liver tumor is a promising technique.

Cold ischemia is a major determinant of acute rejection and renal graft survival in the modern era of immunosuppression.

Background. The aim of our study was to examine, in a recent cohort of kidney transplant recipients who have received modern immunosuppressive therapy, the respective role of cold ischemia time (CIT) and delayed graft function (DGF) on acute rejection (AR) rates and long-term graft survival. Methods. We retrospectively reviewed the charts of 611 renal transplantations between 1996 and 2005. Most patients received a calcineurin inhibitor as maintenance therapy, either cyclosporine (43%) or tacrolimus (52%) and 76% of the patients received an antilymphocyte induction therapy. Study endpoints were DGF, first-year AR, and long-term graft survival. Uni- and multivariate analyses were performed to determine factors that may have influenced the study outcomes. Results. DGF was observed in 16.2% of patients. Both older donor age and longer CIT were significant risk factors for DGF. DGF rates were similar whether patients received a calcineurin inhibitor before transplantation or not. AR occurred in 16.5% of grafts during the first year. Independent predictors of AR by multivariate analysis were duration of dialysis, CIT, current panel-reactive lymphocytotoxic antibody more than 5%, and the number of human leukocyte antigen-A, B, and DR mismatches. Each hour of cold ischemia increases the risk of rejection by 4%. With respect to death-censored graft survival, three pretransplant parameters emerged as independent predictors of graft loss: younger recipient age, peak panel-reactive lymphocytotoxic antibody more than 5% and longer CIT. The detrimental effect of CIT on graft survival was entirely because of its propensity to trigger AR. When AR was added to the multivariate Cox model, CIT was no longer significant whereas first-year AR became the most important predictor of graft loss (Hazards ratio, 4.6). Conclusion. Shortening CIT will help to decrease not only DGF rates but also AR incidence and hence graft loss. Patients with prolonged CIT should receive adequate immunosuppression, possibly with antilymphocyte preparations, to prevent AR occurrence.

Critical role of interleukin 4 in the induction of neonatal transplantation tolerance

Neonatal injection of semiallogeneic cells is known to promote differentiation of donor-specific CD4+ T cells into TH2-like cells in the peripheral lymphoid organs. We reasoned that the propensity of neonatal T cells to synthesize high levels of IL-4 might be involved in this polarization of the alloreactive response and thereby in the development of neonatal transplantation tolerance. First, analysis of cytokine gene expression in lymph nodes after neonatal injection of 107 (A/J×BALB/c)Fl cells in BALB/c mice indicated that IL-4 but not IL-2 is rapidly produced by CD4+ cells after allogeneic challenge in vivo. To determine whether the early production of IL-4 was involved in the establishment of allotolerance, BALB/c mice neo-natally injected with (A/JxBALB/c)Fl spleen cells received on days 1 and 3 after birth 1 mg of anti-IL-4 mAb (11B11) or the same amount of control mAb. When grafted with A/J skin at 4 weeks, 88% of mice treated with control mAb retained their graft for more than 50 days, whereas rejection occurred within 30 days in 93% of mice treated with anti-IL-4 mAb. Analysis of T cell functions after in vitro restimulation with A/J spleen cells indicated that early IL-4 neutralization did not prevent donor-specific CTL unresponsiveness but allowed the emergence of alloreactive T cells secreting increased levels of IL-2 and IFN–y. We conclude that early production of IL-4 is critical for the establishment of neonatal transplantation tolerance in this strain combination, which has disparities across the entire H-2 region.

Advancement of mesenchymal stem cell therapy in solid organ transplantation (MISOT).

There is evolving interest in the use of mesenchymal stem cells (MSC) in solid organ transplantation. Pre-clinical transplantation models show efficacy of MSC in prolonging graft survival and a number of clinical studies are planned or underway. At a recent meeting of the MISOT consortium (MSC In Solid Organ Transplantation) the advances of these studies were evaluated and mechanisms underlying the potential effects of MSC discussed. Continued discussion is required for definition of safety and eventually efficacy endpoints for MSC therapy in solid organ transplantation.

IL-12 prevents neonatal induction of transplantation tolerance in mice.

We investigated the effect of IL‐12 on the induction of transplantation tolerance by neonatal injection of allogenic cells. We first observed that injection of newborn BALB/c mice with IL‐12 and (A/J × BALB/c) F1 spleen cells prevented the Th2 alloimmune response induced by neonatal inoculation of F1 cells alone and allowed the differentiation of T cells secreting high amounts of IL‐2 and IFN‐γ in mixed lymphocyte cultures with donor‐type stimulators. Furthermore, IL‐12 administration resulted in the emergence of anti‐donor cytotoxic T lymphocyte responses although at lower levels than in control uninjected mice. In parallel, we found that mice injected at birth with IL‐12 and F1 cells did not develop chimerism and were able to reject a donor‐type skin graft as efficiently as control mice. We conclude that IL‐12 inhibits the Th2 polarization of the newborn response to alloantigens and prevents thereby the establishment of transplantation tolerance.

Invasive aspergillosis in patients with severe alcoholic hepatitis

BACKGROUND & AIMS Severe alcoholic hepatitis (AH) has a poor short-term prognosis. Although infections are frequent complications of AH, the incidence of invasive aspergillosis (IA) and its impact on outcome remain unknown. METHODS We prospectively followed 94 biopsy-proven severe AH episodes for 3 months. We retrospectively reviewed our diagnosis of IA based on EORTC/MSG and AspICU criteria, except for host factors. RESULTS Fifteen IA (6 proven, 8 probable, and 1 possible) were diagnosed after a median delay of 26 days following diagnosis of AH. The sites of infection were the lungs (n=11) and central nervous system (n=2), while IA was disseminated in 2 cases. Baseline MELD score ≥24 and ICU admission were independent risk factors for IA. Thirteen IA occurred in the context of corticosteroids, and 2 had received no specific treatment for AH. Non-response to corticosteroids at day 7 was not a risk factor for IA, but IA was associated with absence of liver improvement at day 28. Despite antifungal treatment, 3-month transplant-free survival of patients with IA was 0% compared to 53% in those without IA. IA, Lille score ≥0.45, and overt encephalopathy were independent predictors of transplant-free mortality. CONCLUSIONS IA is a frequent complication of severe AH and carries a very high risk of mortality. Systematic screening for IA should be recommended in these patients. Further studies are needed to identify high-risk populations requiring antifungal prophylactic treatment.

Liver transplantation from donation after cardiac death donors: initial Belgian experience 2003–2007

The Belgian experience with donation after cardiac death (DCD) liver transplantation (LT) was retrospectively reviewed, particularly evaluating patient and graft survivals, and biliary complications. From 2003 to 2007, 58 DCD‐LT were performed in Belgium. Mean procurement total warm ischemia time was 25 ± 2 min (mean ± SEM). Mean cold ischemia time was 451 ± 18 min. Mean follow‐up was 23 ± 2.2 months. Post‐transplant peak aspartate aminotransminases was 2241 ± 338 UI/l. Patient survivals at 1 month, 1 and 3 years, were 91.3%, 83.3% and 66.9% respectively. Graft survivals at 1 month, 1 and 3 years, were 84.4%, 72.4% and 48.8% respectively. Two patients (3.4%) developed primary nonfunction. Regarding the biliary complications, seven grafts (12%) were lost because of intrahepatic cholangiopathy, and 12 other patients (20.6%) developed bile duct stenoses requiring endoscopic and/or surgical management. The rate of symptomatic ischemic biliary lesions for grafts surviving more than 3 months was 38% (19/50). Although DCD organ donors may be a source of viable liver grafts, results were inferior to those obtained with donation after brain death LT in this series. Prognostic criteria have to be developed to improve results of DCD‐LT.

Ethical considerations regarding early liver transplantation in patients with severe alcoholic hepatitis not responding to medical therapy.

A recent study proposed that liver transplantation may represent life-saving treatment in patients with severe alcoholic hepatitis not responding to medical therapy. In this pilot experience, stringent patient selection resulted in major improvement of short-term survival with low rates of post-transplant alcohol relapse. In the context of organ shortage, which imposes a need for strict selection of transplant candidates, these results raise major ethical questions. Reluctance to perform liver transplantation in alcoholics is based on the fact that alcoholism is frequently considered to be self-inflicted and on fears of harmful post-transplant alcoholism recurrence. A minimal interval of sobriety lasting at least 6 months is a widely adopted criterion for the selection of patients with alcoholic liver disease for liver transplantation. In severe alcoholic hepatitis, the disastrous short-term prognosis in patients not responding to medical therapy does not allow one to reasonably impose an arbitrary period of 6-months of abstinence. This means that these patients must be either systematically excluded from transplantation or selected according to other criteria. Without significant pre-transplant abstinence, it might be argued that these patients do not merit a graft as they have not demonstrated their ability to gain control over their disease through durable modification of their behaviour. Consequently, this procedure could have a negative impact in the public, affecting organ donation and confidence in the fairness of transplant programs. In contrast, ethical principles recommend active treatment of patients, without discrimination, according to the best scientific knowledge. At this stage, we propose that there are no major ethical barriers for further evaluation of this new therapeutic option. The next steps should include transparent communication with the public and further studies to reproduce these results and identify the selection criteria that provide the best long-term outcomes.