Immunosuppression Weaning Research Articles

Late Treatment With Autologous Expanded Regulatory T-cell Therapy After Alemtuzumab Induction Is Safe and Facilitates Immunosuppression Minimization in Living Donor Renal Transplantation.

The TWO Study (Transplantation Without Overimmunosuppression) aimed to investigate a novel approach to regulatory T-cell (Treg) therapy in renal transplant patients, using a delayed infusion protocol at 6 mo posttransplant to promote a Treg-skewed lymphocyte repopulation after alemtuzumab induction. We hypothesized that this would allow safe weaning of immunosuppression to tacrolimus alone. The COVID-19 pandemic led to the suspension of alemtuzumab use, and therefore, we report the unique cohort of 7 patients who underwent the original randomized controlled trial protocol. This study presents a unique insight into Treg therapy combined with alemtuzumab and is therefore an important proof of concept for studies in other diseases that are considering lymphodepletion. Living donor kidney transplant recipients were randomized to receive autologous polyclonal Treg at week 26 posttransplantation, coupled with weaning doses of tacrolimus, (Treg therapy arm) or standard immunosuppression alone (tacrolimus and mycophenolate mofetil). Primary outcomes were patient survival and rejection-free survival. Successful cell manufacturing and cryopreservation until the 6-mo infusion were achieved. Patient and transplant survival was 100%. Acute rejection-free survival was 100% in the Treg-treated group at 18 mo after transplantation. Although alemtuzumab caused a profound depletion of all lymphocytes, including Treg, after cell therapy infusion, there was a transient increase in peripheral Treg numbers. The study establishes that delayed autologous Treg therapy is both feasible and safe, even 12 mo after cell production. The findings present a new treatment protocol for Treg therapy, potentially expanding its applications to other indications.

The Effects of Sustained Immunosuppression Withdrawal After Liver Transplantation on Metabolic Syndrome.

Liver transplant (LT) recipients often experience adverse effects of immunosuppressive (IS) drugs, especially on metabolic profiles. Selected LT recipients can achieve successful IS withdrawal; however, its effects on metabolic syndrome (MS) are unknown. This is a retrospective single-center study investigating the incidence and/or regression of MS in 75 selected LT recipients who were previously enrolled in prospective IS withdrawal trials between 1999 and 2017. Patients who were transplanted due to nonalcoholic steatohepatitis/metabolic-associated fatty liver disease were excluded, as well as those with a follow-up <3 y after IS weaning. Forty-four patients (58.7%) achieved sustained withdrawal or minimization of immunosuppression (WMIS) and 31 patients (41.3%) required reintroduction of immunosuppression (no-WMIS). Among LT recipients who were metabolically healthy (n = 52, 69.3%) before the start of IS weaning, there was a significantly lower rate of de novo MS in WMIS patients compared with no-WMIS patients after 5 y (8.3% and 47.8%, respectively, P = 0.034). Of 23 LT recipients (30.7%) who had MS at the time of commencing IS withdrawal, complete regression of MS was observed in 47.1% of WMIS patients and in none (0%) of the no-WMIS patients after 5 y (P = 0.054). Furthermore, individual components of MS were better controlled in IS-weaned patients, such as arterial hypertension and abnormal serum lipids. Achievement of sustained IS withdrawal reduces the incidence of de novo MS development in metabolically healthy patients and increases the likelihood of MS regression in patients with established MS. The foreseeable long-term beneficial effects of these favorable metabolic changes on morbidity and mortality of LT recipients require further investigation.

Allograft nephrectomy vs. no nephrectomy for failed renal transplants.

The role of allograft nephrectomy (AN) in failed renal transplants is a topic of debate, owing to controversial results reported in the literature and the fact that most of the studies are limited by a retrospective design and small numbers of participants. Allograft nephrectomy is most likely of benefit in the patient with recurrent allograft intolerance syndrome (AIS) following pulse steroids. Immunosuppression weaning in the presence of clinical signs related to a chronic inflammatory state is also reasonable grounds to pursue AN. Studies are mainly inconclusive but suggest that AN has no overall benefit for allograft survival after retransplant. This topic is still of interest in the transplant field and is particularly relevant for patients who are likely to require retransplantation within their lifetime. Further assessment is needed in the form of randomized controlled trials that control for various AN indications and immunosuppression regimens, and have clearly defined survival outcomes.

Continuation of immunosuppression vs. immunosuppression weaning in potential repeat kidney transplant candidates: a care management perspective.

Management of immunosuppression in patients with a failing or failed kidney transplant requires a complete assessment of their clinical condition. One of the major considerations in determining immunosuppression is whether or not such an individual is considered a candidate for re-transplantation. Withdrawal of immunosuppression in a re-transplant candidate can result in allosensitization and markedly reduce the chances of a repeat transplant. In this review, we summarize the effects of immunosuppression reduction on HLA sensitization, discuss the impacts of allosensitization in these patients, and explore reduction protocols and future directions. Risks of chronic immunosuppression, medical management of the failing allograft, and the effect of nephrectomy are covered elsewhere in this issue.

Revisiting maintenance immunosuppression in patients with renal transplant failure: early weaning of immunosuppression versus prolonged maintenance-systematic review and meta-analysis.

Prolonged immunosuppressionafter dialysis start has been assumed to reduce sensitization, need forgraft nephrectomy, and to favor re-transplantation. In contrast, immunosuppression is considered to increase the risk of mortality, infection, and malignancy. We aimed to assess the evidence regarding superiority of early or late withdrawal of maintenance immunosuppression post renal transplant failure. A literature search of the PubMed, WOS, Ovid, and Scopus databases was conducted. Combined relative risks, (RRs), mean differences, and 95% confidence intervals (CIs) were calculated by using a random-effect model. Ten studies involving 1187 patients with kidney transplant failurewere included. No difference could be detected between patients with early withdrawal of immunosuppressive drugs(≤ 3months) or prolonged immunosuppressive treatment (> 3months) regarding mortality (95% CI 0.91-2.28), panel reactive antibodies (PRAs) (95% CI - 0.75-30.10), re-transplantation rate (95% CI 0.55-1.35), infectious episodes (95% CI 0.67, 1.17), cancer (95% CI 0.26-1.54), and graft nephrectomy (95% CI 0.82-1.63). Similarly, no difference was found between immunosuppressive drug withdrawal over < 6 or ≥ 6months regarding mortality (95% CI 0.16, 2.89), re-transplantation rate (95% CI 0.85-1.55), cancer (95% CI 0.37-1.63), and allograft nephrectomy (95% CI 0.87-4.33). Prolonged maintenance immunosuppression post kidney transplant failureis not associated with increased risk of mortality, infection, or malignancy, or reduced risk of sensitization or allograft nephrectomy compared with early withdrawal.

Low dose interleukin-2 selectively expands circulating regulatory T cells but fails to promote liver allograft tolerance in humans

CD4+CD25+Foxp3+ regulatory T cells (Tregs) are essential to maintain immunological tolerance and have been shown to promote liver allograft tolerance in both rodents and humans. Low-dose IL-2 (LDIL-2) can expand human endogenous circulating Tregs invivo, but its role in suppressing antigen-specific responses and promoting Treg trafficking to the sites of inflammation is unknown. Likewise, whether LDIL-2 facilitates the induction of allograft tolerance has not been investigated in humans. We conducted a clinical trial in stable liver transplant recipients 2-6 years post-transplant to determine the capacity of LDIL-2 to suppress allospecific immune responses and allow for the complete discontinuation of maintenance immunosuppression (ClinicalTrials.gov NCT02949492). One month after LDIL-2 was initiated, those exhibiting at least a 2-fold increase in circulating Tregs gradually discontinued immunosuppression over a 4-month period while continuing LDIL-2 for a total treatment duration of 6 months. All participants achieved a marked and sustained increase in circulating Tregs. However, this was not associated with the preferential expansion of donor-reactive Tregs and did not promote the accumulation of intrahepatic Tregs. Furthermore, LDIL-2 induced a marked IFNγ-orchestrated transcriptional response in the liver even before immunosuppression weaning was initiated. The trial was terminated after the first 6 participants failed to reach the primary endpoint owing to rejection requiring reinstitution of immunosuppression. The expansion of circulating Tregs in response to LDIL-2 is not sufficient to control alloimmunity and to promote liver allograft tolerance, due, at least in part, to off-target effects that increase liver immunogenicity. Our trial provides unique insight into the mechanisms of action of immunomodulatory therapies such as LDIL-2 and their limitations in promoting alloantigen-specific effects and immunological tolerance. The study is registered at ClinicalTrials.gov (NCT02949492). The administration of low-dose IL-2 is an effective way of increasing the number of circulating regulatory T cells (Tregs), an immunosuppressive lymphocyte subset that is key for the establishment of immunological tolerance, but its use to promote allograft tolerance in the setting of clinical liver transplantation had not been explored before. In liver transplant recipients on tacrolimus monotherapy, low-dose IL-2 effectively expanded circulating Tregs but did not increase the number of Tregs with donor specificity, nor did it promote their trafficking to the transplanted liver. Low-dose IL-2 did not facilitate the discontinuation of tacrolimus and elicited, as an off-target effect, an IFNγ-orchestrated inflammatory response in the liver that resembled T cell-mediated rejection. These results, supporting an unexpected role for IL-2 in regulating the immunogenicity of the liver, highlight the need to carefully evaluate systemic immunoregulatory strategies with investigations that are not restricted to the blood compartment and involve target tissues such as the liver.

Minimal Development of Liver Fibrosis in Adult Tolerant Liver Transplant Recipients Late After Immunosuppressive Drug Weaning and Transplantation

Operationally tolerant liver transplant (LTx)-recipients can be weaned off immunosuppressive (IS) drugs without development of graft rejection. However, it is feared that liver fibrosis might develop after complete IS weaning. The purpose of this small single-center study was to assess liver fibrosis in adult tolerant LTx recipients long after LTx and IS weaning. Liver fibrosis was assessed in adult tolerant LTx-recipients (n=9) using noninvasive transient elastography and measurements of multiple pro- and antifibrotic serum markers associated with liver fibrosis. The data was collected for 2 subsequent years; 8 and 9 years after IS weaning and 19 and 20 years after transplantation. Healthy individuals (n=9) matched for age and sex were included as a reference for fibrosis-related serum markers. This study was conducted in accordance with the Declaration of Helsinki and approved by the medical ethics committee of our institution. Transient elastography indicated that 7 of 9 tolerant LTx recipients had no or minimal liver fibrosis (F0-F1), whereas 2 recipients had moderate or severe liver fibrosis (F2-F3). Most fibrosis-related serum markers in tolerant LTx recipients were within or close to the range obtained for healthy individuals. The results from this small, single-center study indicated that most adult tolerant LTx recipients have no or minimal liver graft fibrosis long after transplantation and IS weaning, and their fibrosis-related serum marker profile indicates an absence of a profibrotic status.

P8.071: Outcomes in Kidney Transplant Recipients With Allograft Failure Who Return to Dialysis

Background: Kidney transplant recipients (KTR) who return to dialysis (RTD) have high morbidity. Whether to continue immunosuppression (IS) after RTD remains uncertain and involves balancing IS-related risks with preventing terminal rejection and allo-sensitization that may preclude re-transplantation. Objectives: We conducted a quality improvement study to characterize IS practices following RTD, and determine incidence of potential IS-related complications, catastrophic IS-related events, and re-transplantation for patients in whom IS was weaned early vs. late. Methods: We identified all adult KTR who RTD and survived >6 months between January 2015-June 2020 at a large Canadian transplant center using this center’s transplant and dialysis databases. Comorbidities, medications, and outcomes were captured from electronic charts on pre-specified forms from RTD until death, re-transplantation, or Aug 2021. Early IS weaning was defined as discontinuing at least one agent excluding prednisone within 6 months of RTD. Results: Of 49 included patients, 27(55%) discontinued one IS agent by 6 months, while 22(45%) were maintained on two for a median of 34 months (range 7-78 months). During median follow-up of 29 months (range 3-78), there were no between-group differences in the proportion of patients who experienced all-cause (16/27 vs. 12/22) or infection-related (8/27 vs. 7/22) hospitalisations, ICU admission (5/27 vs. 5/22), malignancy (3/27 vs. 2/22), death (6/27 vs.4/22), terminal rejection (3/27 vs. 2/22), or re-transplantation (7/27 vs. 5/22). Median baseline PRA was significantly higher in early vs. late groups, suggesting confounding by indication. Two catastrophic IS events (disseminated tuberculosis, PTLD) occurred in late weaners. Conclusion: Almost half of KTR continued long-term double IS after RTD, and retransplantation rates were low. Cancer and death were not increased in late vs. early IS weaners, but catastrophic infection and PTLD occurred only in late weaners. Early discontinuation of one IS agent did not result in lower probability of re-transplantation and should be considered to reduce infectious complications.

Reducing Immunosuppression in Patients with De Novo Lung Carcinoma after Liver Transplantation Could Significantly Prolong Survival

Simple SummaryLong-term immunosuppressive therapy following liver transplantation is associated with an increased risk for the development of de novo lung carcinoma. However, data on the management of the immunosuppression following the diagnosis of lung cancer are missing to the present day. In this retrospective analysis, we investigate factors associated with improved survival of liver transplant recipients with diagnosis of de novo lung carcinoma with a particular emphasis on the impact of immunosuppression. Our findings suggest that strict reduction of immunosuppression has a beneficial effect on survival in this particular situation and, thus, should be an early intervention following diagnosis. Liver transplant recipients with the diagnosis of de novo lung cancer should be offered surgical treatment if technically feasible as a potential curative therapeutic option to improve limited prognosis. Further investigations concerning dosage findings and reduction of immunosuppression in organ recipients should be the targets of subsequent studies.(1) Background: Liver transplantation (LT) is an established treatment for selected patients with end-stage liver disease resulting in a subsequent need for long-term immunosuppressive therapy. With cumulative exposure to immunosuppression (IS), the risk for the development of de novo lung carcinoma increases. Due to limited therapy options and prognosis after diagnosis of lung cancer, the question of the mode and extent of IS in this particular situation is raised. (2) Methods: All patients diagnosed with de novo lung cancer in the follow-up after LT were identified from the institution’s register of liver allograft recipients (Charité—Universitätsmedizin Berlin, Germany) transplanted between 1988 and 2021. Survival analysis was performed based on the IS therapy following diagnosis of lung cancer and the oncological treatment approach. (3) Results: Among 3207 adult LTs performed in 2644 patients at our institution, 62 patients (2.3%) developed de novo lung carcinoma following LT. Lung cancer was diagnosed at a median interval of 9.7 years after LT (range 0.7–27.0 years). Median survival after diagnosis of lung carcinoma was 13.2 months (range 0–196 months). Surgical approach with curative intent significantly prolonged survival rates compared to palliative treatment (median 67.4 months vs. 6.4 months). Reduction of IS facilitated a significant improvement in survival (median 38.6 months vs. 6.7 months). In six patients (9.7%) complete IS weaning was achieved with unimpaired liver allograft function. (4) Conclusion: Reduction of IS therapy after the diagnosis of de novo lung cancer in LT patients is associated with prolonged survival. The risk of acute rejection does not appear to be increased with restrictive IS management. Therefore, strict reduction of IS should be an early intervention following diagnosis. In addition, surgical resection should be attempted, if technically feasible and oncologically meaningful.

The use of transient elastography in identifying sub-clinical chronic ductopenic rejection in adult liver transplant recipients: A case series

BackgroundTransient elastography has become a standard tool for the accurate non-invasive assessment of liver stiffness and fat content. Liver transplant recipients can develop allograft fibrosis during long-term follow-up despite normal or mildly abnormal liver chemistries. Tapering of immunosuppression in long-term liver transplant survivors is performed relying solely on liver chemistries. It is important to know if underlying liver histology would be abnormal or if rejection was present as this would alter the desire to decrease stable maintenance doses of immunosuppression. MethodsWe present our experience of five liver transplant recipients who had transient elastography performed prior to consideration of weaning of their immunosuppression. ResultsAll five patients showed signs of elevated liver stiffness on transient elastography in the setting of normal to slightly abnormal liver tests with very stable immunosuppressant doses. This prompted the performance of liver biopsies which demonstrated immune-mediated liver injury and thus negated the immunosuppression withdrawal. ConclusionTransient elastography has utility as a non-invasive method to evaluate allograft health in long-term liver transplant survivors and can be useful in the decision-making process for immunosuppression weaning.

Clinical liver transplant tolerance: Recent topics.

Immunosuppression is essential after organ transplantation to prevent severe graft injury due to rejection, but in long-term, transplanted organs are generally accepted with minimal dose of immunosuppression, and adverse effects of it such as renal dysfunction, diabetes and development of malignancies might become to exceed over the benefits in majority of the cases. Accordingly, to achieve the immunologic tolerance has been the ultimate goal in organ transplantation, and the liver has been well recognized as the tolerogenic organ compared to other organs. We referred the reported studies showing the actual protocol to achieve the immunologic tolerance after clinical liver transplantation. Actually, two main procedures as "elective weaning of immunosuppression" and/or "cell therapy" using various immune-related cells have been introduced to induce the immunologic tolerance in clinical liver transplantation. The cell therapy, especially using regulatory T-cell has been reported to achieve definitive immunologic tolerance in living donor liver transplantation. Although it is still developing, the induction of immunologic tolerance in clinical liver transplantation is realistic. Herein, the current topics of immunologic tolerance in liver transplantation is described.

The Failing Kidney Transplant Allograft. Transplant Nephrectomy: Current State-of-the-Art.

This review provides a critical literature overview of the risks and benefits of transplantectomy in patients with a failed allograft. Additionally, it offers a summary of related problems, primarily alloantibody sensitization in the event of nephrectomy and immunosuppression weaning. Transplant nephrectomy has high morbidity and mortality rates. The morbidity of transplant nephrectomy (4.3 to 82%) is mostly due to hemorrhage or infection. Mortality rates range from 1.2 to 39%, and most are due to sepsis. Transvascular graft embolization has been described as a less invasive alternative technique for the management of symptomatic graft rejection, with minimal complications compared with transplantectomy. The number of patients with a failed allograft returning to dialysis is increasing. The role of allograft nephrectomy in the management of asymptomatic transplant failure is still controversial and up today continues to depend on the usual clinical practice of each institution. The less invasive transvascular embolization could have applicability in asymptomatic patients with the obvious lower morbidity and mortality rate.

Is diverting loop ileostomy necessary for completion proctectomy with ileal pouch-anal anastomosis? A multicenter randomized trial of the GETAID Chirurgie group (IDEAL trial): rationale and design (NCT03872271)

BackgroundThere is no quality evidence of the benefit of defunctioning ileostomy (DI) in ileal pouch-anal anastomoses (IPAAs) performed for inflammatory bowel disease (IBD), but most surgical teams currently resort to DI. In the case of a staged procedure with subtotal colectomy first, completion proctectomy with IPAA is performed for healthy patients, namely, after nutritional support, inflammation reduction and immunosuppressive agent weaning. Therefore, the aim of this trial is to assess the need for systematic DI after completion proctectomy and IPAA for IBD.Methods/designThis is a multicenter randomized open trial comparing completion proctectomy and IPAA without (experimental) or with (control) DI in patients presenting with ulcerative colitis or indeterminate colitis. Crohn’s disease patients will not be included. The design is a superiority trial. The main objective is to compare the 6-month global postoperative morbidity, encompassing both surgical and medical complications, between the two groups. The morbidity of DI closure will be included, as appropriate. The sample size calculation is based on the hypothesis that the overall 6-month morbidity rate is 30% in the case of no stoma creation (i.e., experimental group) vs. 55% otherwise (control group). With the alpha risk and power are fixed to 0.05 and 0.80, respectively, and considering a dropout rate of 10%, the objective is set to 194 patients. The secondary objectives are to compare both strategies in terms of morbi-mortality at 6 months and functional results as well as quality of life at 12 months, namely, the 6-month major morbidity and unplanned reoperation rates, 6-month anastomotic leakage rate, 6-month mortality, length of hospital stay, 6-month unplanned readmission rate, quality of life assessed 3 and 12 months from continuity restoration (i.e., either IPAA or stoma closure), functional results assessed 3 and 12 months from continuity restoration, 12-month pouch results, 12-month cost-utility analysis, and 12-month global morbidity.DiscussionThe IDEAL trial is a nationwide multicenter study that will help choose the optimal strategy between DI and no ileostomy in completion proctectomy with IPAA for IBD.Trial registrationClinicalTrial.gov: NCT03872271, date of registration March 13th, 2019.

De novo malignancies after liver transplantation: The effect of immunosuppression-personal data and review of literature.

BACKGROUNDImmunosuppression has undoubtedly raised the overall positive outcomes in the post-operative management of solid organ transplantation. However, long-term exposure to immunosuppression is associated with critical systemic morbidities. De novo malignancies following orthotopic liver transplants (OLTs) are a serious threat in pediatric and adult transplant individuals. Data from different experiences were reported and compared to assess the connection between immunosuppression and de novo malignancies in liver transplant patients.AIMTo study the role of immunosuppression on the incidence of de novo malignancies in liver transplant recipients.METHODSA systematic literature examination about de novo malignancies and immunosuppression weaning in adult and pediatric OLT recipients was described in the present review. Worldwide data were collected from highly qualified institutions performing OLTs. Patient follow-up, immunosuppression discontinuation and incidence of de novo malignancies were reported. Likewise, the review assesses the differences in adult and pediatric recipients by describing the adopted immunosuppression regimens and the different type of diagnosed solid and blood malignancy.RESULTSEmerging evidence suggests that the liver is an immunologically privileged organ able to support immunosuppression discontinuation in carefully selected recipients. Malignancies are often detected in liver transplant patients undergoing daily immunosuppression regimens. Post-transplant lymphoproliferative diseases and skin tumors are the most detected de novo malignancies in the pediatric and adult OLT population, respectively. To date, immunosuppression withdrawal has been achieved in up to 40% and 60% of well-selected adult and pediatric recipients, respectively. In both populations, a clear benefit of immunosuppression weaning protocols on de novo malignancies is difficult to ascertain because data have not been specified in most of the clinical experiences.CONCLUSIONThe selected populations of tolerant pediatric and adult liver transplant recipients greatly benefit from immunosuppression weaning. There is still no strong clinical evidence on the usefulness of immunosuppression withdrawal in OLT recipients on malignancies. An interesting focus is represented by the complete reconstitution of the immunological pathways that could help in decreasing the incidence of de novo malignancies and may also help in treating liver transplant patients suffering from cancer.

Association between musk antibody concentrations and the myasthenia gravis composite score in 3 patients: A marker of relapse?

Muscle-specific tyrosine kinase (MuSK) autoantibody related myasthenia gravis is characterized by bulbar and respiratory manifestations, a poor response to anticholinergics, and a generally good response to plasma exchange and rituximab. It is not known if MuSK-antibody (Ab) levels could be used to predict the clinical course Methods: Three patients for whom frequent long-term monitoring of MuSK-Ab levels and the Myasthenia Gravis Composite (MGC) scores were performed are described. A close relationship existed between the MuSK-Ab concentrations and the MGC score. Furthermore, a rise in Ab concentration preceded a more serious clinical relapse in all patients Conclusions: These findings suggest that MuSK-Ab concentrations may be a useful biomarker for the long-term monitoring of MuSK myasthenia gravis, particularly while in clinical remission. This may allow preemptive escalation of therapy to prevent clinical relapse, and conversely permitting greater weaning of unnecessary immunosuppression. Muscle Nerve, 2019.

Tomotherapy and Hematopoietic Stem Cells for Tolerance to Kidney Transplants in Rhesus Macaques

NIH NHP Transplantation Tolerance Cooperative Study Group. The goal of this project was to develop a tolerance induction protocol for kidney transplantation (tx) in a rhesus macaque model that would permit complete elimination of all immunosuppression (IS). We hypothesized that tolerance to MHC 1-haplotype mismatched kidney tx between living related donor/recipient pairs can be achieved by establishing a mixed chimeric state. The chimeric state would be achieved using a newly established post-kidney tx, non-myeloablative, helical tomotherapy-based total lymphoid irradiation (TLI)-based conditioning regimen followed by donor mobilized peripheral blood-CD34+ hematopoietic stem cell (HSC)/T cell (CD3+) infusions (Figure 1). The hypotheses was tested in a series of 5 HSC-only txs followed by 18 kidney txs with (n=11) and without (n=7) donor HSC infusions. The kidney allografts came from blood group compatible, T and B cell flow cytometric crossmatch negative donors. All recipient animals underwent IS withdrawal according to the same schedule and were followed for rejection. We determined the proportion of recipients that achieved chimerism and that could be withdrawn from all IS for greater than 3 years, while maintaining normal allograft function. Mixed chimerism in the recipient was assessed by quantifying the proportion and duration of donor/recipient DNA, using STR, in various immune cellular lineages circulating within the peripheral blood post-tx. Results are shown in There were 11 kidney+HSC txs. Two achieved transient multilineage chimerism for at least 3 months and both were long-term tolerant survivors (still alive and off IS for more than 3 years). Nine animals in the kidney+HSC group did not achieve any evidence of chimerism – all lost the kidney tx before or during the IS weaning (5 due to rejection, 4 with engraftment syndrome, 1 each from infection and PTLD). All animals in the kidney tx-alone control group lost kidney function, with one having prolonged graft survival without IS, but eventually succumbed to chronic antibody mediated rejection. Furthermore, we assessed the correlation between the presence (n=5, including 3 with HSC-only infusions) or absence (n=8, including 2 with HSC-only infusions and excluding the 4 engraftment syndrome cases) of achieving chimerism and the development of de novo donor specific antibody (DSA) (Figure 3). DSA was absent in all 5 animals that achieved chimerism. Development of early de novo DSA, primarily against Class II MHC, was associated with lack of development of mixed chimerism, and therefore, inability to successfully eliminate IS. The study demonstrated that this TLI-based tolerance induction protocol can result in chimerism and operational tolerance in the rhesus macaque model across a 1-haplo mismatch. However, challenges remain to enhance the frequency of achieving chimerism. Future studies to extend the protocol to animals that are more MHC disparate will include modifications of the conditioning regimen to minimize development of DSA and engraftment syndrome. Funding supported by NIH NIAID.

Cost Effectiveness of Immunosuppression Withdrawal after Liver Transplantation

Background Lifelong immunosuppression (IS) after liver transplantation (LT) is associated with severe side effects and increased recipients morbidity and mortality. Achievement of clinical operational tolerance has been reported up to 40% of LT recipients. We herein report the cost savings reached for the Italian National Health System with operational tolerant recipients. Methods Seventy five LT recipients were previously enrolled for IS withdrawal at our institution between April 1998 and December 2015. Study population included: 32 (42%) patients tolerant that completed the withdrawal of IS therapy; 41 (54%) patients transient tolerant who underwent IS resumption after clinical or biopsy-proven sign of rejection; two (3%) patients non-tolerant who developed early rejection at the first step of drug reduction. The endpoint of this study was to assess the long-term cost saving of IS withdrawal. Results The IS weaning results in a cost saving for the national health Italian system of 634.000 Euros (Figure 1) for a period of 95 months (IQR= 23-109). As a matter of fact, the participation to the IS withdrawal protocol did not result in patient or graft loss during the follow up period. Conclusion: The long term IS withdrawal represents a remarkable cost saving for the national health system without exposing recipients to graft loss.

Using a weaning immunosuppression protocol in liver transplantation recipients with hepatocellular carcinoma: a compromise between the risk of recurrence and the risk of rejection?

Hepatocellular carcinoma (HCC) recurrence rate after liver transplantation (LT) is still up to 15-20%, despite a careful selection of candidates and optimization of the management within the waiting list. To reduce tumour recurrence, the currently adopted post-transplant strategies are based on the administration of a tailored immunosuppression (IS) regimen. Drug-induced depression of the immune system is essential in preventing graft rejection, however has a well-established association with oncogenesis. The immune system has a key role as a defending mechanism against cancer development, preventing vascular invasion and metastasis. Thus, IS drugs represent one of few modifiable non-oncological risk factors for tumour recurrence. In HCC recipients, a tailored IS therapy, with the aim to minimize drugs' doses, is essential to gain the optimal balance between the risk of rejection and the risk of tumour recurrence. So far, a complete withdrawal of IS drugs after LT is reported to be safely achievable in 25% of patients (defined as "operational tolerant"), without the risk of patient and graft loss. The recent identification of non-invasive "bio-markers of tolerance", which permit to identify patients who could successfully withdraw IS therapies, opens new perspectives in the management of HCC after LT. IS withdrawal could potentially reduce the risk of tumour recurrence, which represents the major drawback in HCC recipients. Herein, we review the current literature on IS weaning in patients who underwent LT for HCC as primary indication and we report the largest experiences on IS withdrawal in HCC recipients.

Infusion of mesenchymal stromal cells after deceased liver transplantation: A phase I–II, open-label, clinical study

Mesenchymal stromal cell (MSC) infusion could be a means to establish tolerance in solid organ recipients. The aim of this prospective, controlled, phase I study was to evaluate the feasibility, safety and tolerability of a single infusion of MSCs in liver transplant recipients. Ten liver transplant recipients under standard immunosuppression received 1.5-3×106/kg third-party unrelated MSCs on postoperative day 3±2, and were prospectively compared to a control group of ten liver transplant recipients. As primary endpoints, MSC infusion toxicity was evaluated, and infectious and cancerous complications were prospectively recorded until month 12 in both groups. As secondary endpoints, rejection rate, month-6 graft biopsies, and peripheral blood lymphocyte phenotyping were compared. Progressive immunosuppression weaning was attempted from month 6 to 12 in MSC recipients. No variation in vital parameters or cytokine release syndrome could be detected during and after MSC infusion. No patient developed impairment of organ functions (including liver graft function) following MSC infusion. No increased rate of opportunistic infection or de novo cancer was detected. As secondary endpoints, there was no difference in overall rates of rejection or graft survival. Month-6 biopsies did not demonstrate a difference between groups in the evaluation of rejection according to the Banff criteria, in the fibrosis score or in immunohistochemistry (including Tregs). No difference in peripheral blood lymphocyte typing could be detected. The immunosuppression weaning in MSC recipients was not successful. No side effect of MSC infusion at day 3 after liver transplant could be detected, but this infusion did not promote tolerance. This study opens the way for further MSC or Treg-based trials in liver transplant recipients. Therapy with mesenchymal stromal cells (MSCs) has been proposed as a means to improve results of solid organ transplantation. One of the potential MSC role could be to induce tolerance after liver transplantation, i.e. allowing the cessation of several medications with severe side effects. This study is the first-in-man use of MSC therapy in ten liver transplant recipients. This study did not show toxicity after a single MSC infusion but it was not sufficient to allow withdrawal of immunosuppression. Eudract: # 2011-001822-81, ClinicalTrials.gov: # NCT 01429038.

“Cryptic” mediastinal tuberculosis with myasthenia-thymoma complex

Mediastinal tuberculosis, although common in endemic areas, is rare in association with myasthenia-thymoma complex. Immunosuppressive therapy for myasthenia with thymoma might increase the susceptibility for mediastinal tuberculosis. Previous reports suggest aggravation of myasthenic symptoms with this association. This rare combination of pathologies adds to the diagnostic dilemma of the surgeon. Further research is warranted in the management aspects of this combination as regards to the timing of radiotherapy, weaning of immunosuppression and anti-tubercular therapy after maximal thymectomy. This case report emphasises the possibility of mediastinal tuberculosis as a differential diagnosis for mediastinal lymphadenopathy in the setting of a preoperative diagnosis of invasive thymoma.