Minimal Immunosuppression Research Articles

Progressive Multifocal Leukoencephalitis In A Patient With Systemic Lupus Erythematosus On Hydroxychloroquine

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the central nervous system. Reactivation of the polyomavirus JC in immunosuppressed patients induces a lytic infection of oligodendrocytes. The disease is usually fatal in a few months and survivors experience severe neurologic deficits. It is well known to be associated with conditions such as HIV, malignancies, organ transplant recipients and those with chronic inflammatory diseases on immunosuppressive therapy. Review of the medical literature revealed only a few case reports of this disease occurring in minimally immunosuppressed patients (1,3,6). We report a patient with systemic lupus erythematosus on minimal iatrogenic immunosuppression that subsequently developed PML.

Mechanisms and Mediators of Inflammation: Potential Models for Skin Rejection and Targeted Therapy in Vascularized Composite Allotransplantation

Vascularized composite allotransplantation (VCA) is an effective treatment option for patients suffering from limb loss or severe disfigurement. However, postoperative courses of VCA recipients have been complicated by skin rejection, and long-term immunosuppression remains a necessity for allograft survival. To widen the scope of this quality-of-life improving procedure minimization of immunosuppression in order to limit risks and side effects is needed. In some aspects, the molecular mechanisms and dynamics of skin allograft rejection seem similar to inflammatory skin conditions. T cells are key players in skin rejection and are recruited to the skin via activation of adhesion molecules, cytokines, and chemokines. Blocking these molecules has not only shown success in the treatment of inflammatory dermatoses, but also prolonged graft survival in various models of solid organ transplantation. In addition to T cell recruitment, ectopic lymphoid structures within the allograft associated with chronic rejection in solid organ transplantation might contribute to the strong alloimmune response towards the skin. Selectively targeting the molecules involved offers exciting novel therapeutic options in the prevention and treatment of skin rejection after VCA.

Handtransplantation - Fiktion oder Realität?

Hand transplantation has been indicated in selective patients after traumatic upper extremity amputation and only performed in a few centers around the world for the last decade. In comparison to solid organ transplantation, there is a challenge to overcome the host immunological barrier due to complex antigenicity of the different included tissues, the skin being the most susceptible to rejection. Patients require lifelong immunosuppression for non life-threatening conditions. Minimization of maintenance immunosuppression represents the key step for promoting wider applicability of hand transplantation. Current research is working towards the understanding mechanisms of composite tissue allograft (CTA) rejection. Worldwide, in 51 patients 72 hands (21 double hand transplants) and once both arms have been successfully transplanted since 1998.

Allospecific CD154 + T-cytotoxic memory cells as potential surrogate for rejection risk in pediatric intestine transplantation

Clinical end-points dictate large trial enrollments and exclude children with the rare intestine transplant procedure (ITx), who experience higher drug-related morbidity. We evaluate the novel rejection-risk parameter, allo-(antigen)-specific CD154 + TcMs (i) as surrogates for ACR using Prentice's criteria, (ii) for association with immunosuppression targets to determine Fleming's surrogate end-point designation, and (iii) as time-to-event end-point in a simulated comparison of alemtuzumab (NCT#01208337, n = 14) and rabbit anti-human thymocyte globulin (rATG, n = 16) among 30 children with ITx. CD154 + TcM were measured in MLR before, and at 1-60 and 61-200 days after ITx (NCT#01163578). CD154 + TcM correlate significantly with rejection severity (Spearman r = 0.685, p = 2.03E-5) and associate with biopsy-proven ITx rejection with sensitivity/specificity of 94%/84% [corrected] independent of immunosuppressant. Previously stated sensitivity of 90% is incorrect. [corrected]. The rejection-risk threshold of CD154 + TcM resolves rapidly in 200-day follow-up (46 ± 20 vs. 158 ± 59 days, p = 0.009, K-M) with alemtuzumab, which demonstrates lower 90-day ACR incidence (50% vs. 69%, p=NS, Fisher's exact), and is associated with accelerated prednisone minimization to ≤2.5 mg/day, compared with rATG (120 ± 28 vs. 180 ± 30 days, p = 0.027, K-M). As a surrogate end-point, time-to-rejection-risk resolution measured with CD154 + TcM portends 50% reduction in sample sizes in a simulated trial of alemtuzumab vs. rATG. Rejection-risk assessment with CD154 + TcM may enable informed immunosuppression minimization, and preliminary efficacy comparisons in pediatric ITx.

The failure of immunosuppression withdrawal: Patient benefit is not detectable, inducible, or reproducible

(1) Immunosuppression is responsible for excellent patient outcomes. (2) Immunosuppression withdrawal fails in most patients. (3) Patients who may benefit from immunosuppression withdrawal cannot currently be identified. (4) No data suggest that immunosuppression withdrawal decreases patient morbidity (ie, nephrotoxicity). (5) The minimization of immunosuppression instead of withdrawal may be adequate for improving patient outcomes.

Next level of immunosuppression: Drug/immune monitoring

1. Current immunological monitoring relies heavily on clinical judgment and therapeutic drug levels and does not adequately assess the functional or donor-specific immunosuppression (IS) status of recipients of liver transplantation (LT). 2. Trough levels of drugs are arbitrary and are more clinically relevant for preventing supratherapeutic or subtherapeutic dosing and blood concentrations and for more closely monitoring at-risk populations (children, the elderly, and patients with organ dysfunction). The AUC or the post-dose levels may be more precise, but they have not been used extensively by transplant centers. 3. Data on drug/immune monitoring specific to LT are fairly limited; therefore, clinical practice is often borrowed from experiences with nonhepatic transplantation (mainly renal transplantation). 4. The monitoring of drug levels in patients taking generic immunosuppressants is challenging because the formulations may change with each prescription. The monitoring of drug or antibody levels is not yet clinically available for biological therapies (induction, lymphocyte-depleting, and maintenance agents). 5. Polymorphisms in drug metabolism (cytochrome P450 and P-glycoprotein) may be useful in selecting the initial and maintenance dosages of immunosuppressants and in preventing complications from over or underimmunosuppression. 6. Future immune monitoring assays should be focused on genomic or immunological predispositions and on specific reactivities to donor antigens to guide the appropriate dosing and minimization of IS after LT.

Changing picture of central nervous system complications in liver transplant recipients

Central nervous system (CNS) complications are common after liver transplantation (LT). According to the literature, the most common causes are infections and the neurotoxicity of immunosuppressive drugs (cyclosporine and tacrolimus). The aim of this study was to evaluate the incidence, clinical presentations, etiologies, and outcomes of CNS complications in a series of 395 consecutive LT recipients whose immunosuppression regimen was designed for low tacrolimus blood levels. An analysis of the 12-hour trough concentrations of tacrolimus in the study population showed that the target drug levels, which were designed to maintain minimal immunosuppression, were usually achieved. In all, 64 patients (16.2%) developed major neurological symptoms (37 within 30 days of LT). None of the observed CNS complications were caused by infections (viral, bacterial, or fungal), and only 3 of the 395 patients (0.8%) received a diagnosis of tacrolimus-related leukoencephalopathy. Cerebrovascular disease was identified in 15 patients (3.8%; 8 had cerebral hemorrhages, 5 had ischemic strokes, and 2 had subdural hemorrhages). Pontine myelinolysis was found in 2 patients (0.5%). Notably, no clear cause was identified for the remaining 44 cases (11.1%): brain imaging was negative for 22 cases, and diffuse hypoxic changes were present for the other 22. CNS complications were significantly associated with a reduction in 3-month patient survival (88.8% versus 95.4%) and 5-year patient survival (57.3% versus 84.1%). Among the pretransplant variables that were analyzed, the incidence of portosystemic encephalopathy, the peak serum bilirubin levels, and the lowest serum total cholesterol levels were significantly different between the 64-patient group with CNS complications and the asymptomatic group of 331 patients.

The BK virus in renal transplant recipients—review of pathogenesis, diagnosis, and treatment

The BK virus, a DNA virus from the Polyomavirus group, represents an opportunistic infection of immunosuppressed transplant recipients. Though the virus was discovered approximately 40 years ago, the emergence of BK virus nephropathy since 1995 onwards, with associated high graft loss rates, has revolutionized renal transplantation medicine. Kidney transplant professionals realized that the consequences of over-immunosuppression were as severe as the consequences of under-immunosuppression and we entered the era of immunosuppressive minimization. Despite this recognition, the optimal testing type for BK virus infections and frequency of testing are hotly debated. Similarly, optimal treatment strategies remain sources of intense controversy. The authors review the current strategies of screening, diagnosis, and possible treatment, and also review the amount and quality of evidence in favor or against. Similarities and differences between cytomegalovirus, Epstein-Barr virus, and BV virus, the three major viral infections in kidney transplantation, are highlighted.

Renal Graft Function and Low-Dose Cyclosporine Affect Mycophenolic Acid Pharmacokinetics in Kidney Transplantation

In kidney transplantation, the pharmacokinetics of mycophenolic acid (MPA), the active compound of mycophenolate mofetil (MMF), is influenced by concomitant immunosuppressive therapy, including cyclosporine (CsA). However, whether in the setting of immunosuppressive therapy minimization CsA still affects MPA pharmacokinetics, particularly in relation to varying degree of renal graft function deterioration, remains ill defined. One hundred thirty-five complete MPA profiles were sequentially collected from 56 kidney transplant recipients given MMF and low-dose CsA as part of their immunosuppressive therapy. MPA pharmacokinetic parameters were correlated with blood CsA area under the curve (AUC0-12) and graft function as measured glomerular filtration rate (GFR). The relative contribution of CsA exposure and GFR to MPA kinetics in relation to other clinical parameters was determined by multivariate analysis. Dose-adjusted MPA AUC0-12 negatively correlated with CsA AUC0-12. MPA exposure significantly increased when CsA AUC0-12 was below 2000 ng hr/mL. Stratification of MPA profiles according to stages of renal dysfunction showed that dose-adjusted MPA AUC0-12 was higher (P<0.001) in patients with severe (stage 4: 70.37±27.93 μg hr/mL/g MMF) than in those with mild (stage 2: 47.46±11.66 μg hr/mL/g MMF) or moderate (stage 3; 47.48±15.22 μg hr/mL/g MMF) renal insufficiency. At multivariate analysis GFR, serum albumin and hemoglobin levels, use of gastroprotective medications, and time posttransplant were identified as independent determinants of MPA AUC0-12. In stable renal transplant recipients given MMF, tapering CsA dose and deterioration of renal graft function contribute to increased MPA exposure. Thus, monitoring plasma MPA pharmacokinetics should be advised, especially in patients on minimized CsA therapy with severe renal insufficiency.

Efficacy of Pig-to-Rhesus Lamellar Corneal Xenotransplantation

PURPOSE. To solve the shortage of donor corneas, a decellularizing method based on hypertonic saline treatment was introduced, and a favorable outcome was observed in pig-to-rabbit lamellar corneal transplantation. This study was an investigation of the efficacy of pig-to-nonhuman primate lamellar corneal transplantation, using both decellularized and fresh porcine corneas to assess feasibility as a substitute for human corneas. METHODS. Nine Chinese rhesus macaques underwent lamellar corneal transplantation using both decellularized (n = 5) and fresh (n = 4) porcine corneas. Clinically acceptable graft size (7.5 mm in diameter) and minimal immunosuppression based on topical and systemic corticosteroids were applied. Rejection signs, histology of porcine grafts, and serial changes in recipients' blood profile, including memory T-cell subset, anti-α-Gal and donor pig-specific antibodies, and complement were evaluated. Changes in aqueous complement concentration were also assessed at 4 weeks after transplantation. RESULTS. Of the decellularized porcine lamellar grafts, 80% remained transparent for more than 6 months, whereas half of the fresh porcine lamellar grafts developed chronic rejection. Rejected grafts showed extensive cellular infiltration, predominantly CD8(+) T lymphocytes and macrophages. Immunologic profiles of the recipients with rejected grafts showed a significant increase in the concentration of aqueous complement, an enhancement of memory T cells, and an abrupt increase in donor pig-specific antibodies. CONCLUSIONS. The findings suggested that decellularized porcine cornea could be a promising substitute for human corneal allograft. Fresh porcine cornea may be a feasible option for a substitute if combined with more potent immunosuppression or if obtained from transgenic pigs with complement-regulatory proteins.

Some observations on prope tolerance

To outline the rationale of powerful depleting induction therapy with alemtuzumab and minimal maintenance immunosuppression after organ transplantation. The original observations in principle have been confirmed by many independent centres. Follow-up of the 'prope tolerance' protocol has confirmed a low incidence of rejection, infection and post transplant lymphoproliferative disorder (PTLD). Especially, encouraging results were obtained in African-Americans. There were few side effects and the regimen was well tolerated by patients. Treg cells were observed in the circulation, which could be an important factor in the mechanisms of graft acceptance using a prope tolerance regimen. There was a considerable reduction in the costs of the transplantation procedure. It is suggested that this minimalisation of maintenance immunosuppression is the best therapy currently available that we can offer to our patients.

Progressive multifocal leukoencephalopathy associated with isolated CD8+ T-lymphocyte deficiency mimicking tumefactive MS

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system (CNS) caused by lytic infection of oligodendrocytes by the polyomavirus JC (JCV). PML has classically been described in individuals with profound cellular immunosuppression. While some case reports have documented PML in individuals with minimal or occult immunosuppression, such cases are very rare and their pathogenesis is not well understood. We report a unique case of a 74 year-old woman who developed PML clinically mimicking tumefactive multiple sclerosis in the context of an idiopathic isolated CD8+ T-lymphocytopenia. Her course subsequently stabilized, concomitant to the development of a cellular immune response directed against JCV. We review the current literature of related cases and discuss the pathogenesis and implications of this rare presentation.

Operational Tolerance in Living-Related Renal Transplantation: A Single-Center Experience

Introduction Various methods have been tried to induce operational tolerance in organ transplantation. We present a single-center experience using 6 tolerance induction protocols (TIP) in living-related renal transplantation. Methods We evaluated 6 TIP protocols: (1) peripheral blood stem cells employed ( n = 38); (2) midified the protocol by portal infusion ( n = 292); (3) the second protocol plus TIP+DST+BM+intrathymic and intramarrow infusion plus low-dose, nonmyeloablative conditioning employed ( n = 174), (4) the third protocol of TIP plus cultured hematopoietic stem cells (HSC) with target-specific irradiation ( n = 290); (5) TIP 4 plus thymus, intramarrow infusion, and target-specific irradiation converted to total lymphoid irradiation (TLI) ( n = 366); and (6) TIP 5 plus bortzomib–TLI ( n = 165). Patient/donor demographics were comparable. Results We evaluated patient and graft survival, rejection episodes, recurrence, drug toxicity, and chimerism revealed; groups 4 and 5 showed better survival, graft function, chimerism, and decreased rejection episodes compared with previous protocols. Serum creatinine (mg/dL) at 1 year was 1.5, 1.39, 1.5, 1.51, 1.46, and 1.41, and at 5 years, 1.69, 1.72, 1.82 and 1.59, in groups 1–6, respectively. Chronic rejection episodes were 10.5%, 14.1%, 10.4%, 9.3%, 3.5%, 1.7%, and 1.8% respectively. Patient survival of groups 1, 2, and 3 at 1, 5, and 10 years was 86.5%, 56.8%, and 40.1%; 89.4%, 69.1%, and 56.4%; and 89.6%, 67.7%, and 64.6%, respectively; of group 4 for 1 and 5 years was 92.4% and 81.8%; for groups 5 and 6 for 1 year was 94% and 96.3%, respectively. The death-censored graft survival of groups 1, 2, and 3 at 1, 5, and 10 years was 91.9%, 70.3%, and 64.7%; 89%, 66%, and 57.6%; and 86.7%, 67%, and 42.5%, respectively. In group 4 for 1 and 5 years was 87.9% and 74.7%; and for groups 5 and 6 for 1 year was 94% and 96.5%, respectively. Conclusion TIP results showed improved graft/patient survivals, minimum immunosuppression, and fewer rejection episodes and recurrence.

Minimal But Essential Doses of Immunosuppression: A More Realistic Approach to Improve Long-Term Outcomes for Pediatric Living-Donor Liver Transplantation

Minimal But Essential Doses of Immunosuppression: A More Realistic Approach to Improve Long-Term Outcomes for Pediatric Living-Donor Liver Transplantation

80 Can Monotherapy after One Year Post-Transplant Be Effective without Increasing the Risk of Acute Cellular Rejection?

Purpose Multidrug immunosuppression is traditionally implemented to prevent acute cellular rejection (ACR) in cardiac transplant patients despite toxicities. Monotherapy, in contrast, raises concerns of higher risk of immune activation and ACR. We used noninvasive molecular diagnostic testing (MDT) with gene expression profiling to determine if cardiac transplant patients receiving monotherapy with a single calcineurin inhibitor were at greater risk of immune activation and ACR versus those on multi-drug immunosuppression. Methods and Materials 162 patients at least one year post-transplant underwent MDT. 47 (29%) patients were on monotherapy consisting of a single calcineurin inhibitor (CNI), either cyclosporine or tacrolimus. 115 patients were on multi-drug immunosuppression consisting of various combinations of CNI, antiproliferative agents, corticosteroids, and m-TOR inhibitors. Average (±SD) MDT scores were calculated for each group. Results An MDT threshold score of >34 provides a negative predictive value of 98.2 percent that 2R or greater ACR is absent in patients who are at least one year post-transplant. Mean (±SD) MDT scores in the monotherapy group were 28.44±4.62 compared to 29.11±4.08 in the multi-drug immunosuppression group. There was no significant difference in mean MDT scores between the groups (p=.3611). There was no difference in the incidence of 2R or greater ACR between patients on monotherapy and multi-drug immunosuppressive therapy (p=0.18). From the study period of 2005-2010, one patient on monotherapy versus eight patients on multi-drug therapy had 2R ACR. Conclusions 29% of patients more than one year post-transplant were safely managed on monotherapy using MDT. There were no significant differences between the average MDT scores for patients on monotherapy versus multi-drug immunosuppression. Monotherapy did not put patients at increased risk of ACR but facilitated minimization of immunosuppression, potentially improving patient compliance and decreasing risk of adverse side effects.

Transplantation as a subfield of regenerative medicine

Interview by Lauren Constable, Commissioning EditorGiuseppe Orlando, MD, PhD, is a research scientist at the Nuffield Department of Surgical Sciences at the University of Oxford, in quality of Marie Curie International Outgoing Fellow. He obtained his degrees in medicine and general surgery from the Tor Vergata University of Rome (Italy), where he also obtained his PhD in transplant sciences. In addition, he trained at the Liver Unit of the Paul Brousse Hospital (Villejuif, France), at the General Surgery and Liver Transplant Unit of the Cliniques Saint Luc (Brussels, Belgium) and at the Wake Forest Institute for Regenerative Medicine (Winston Salem, NC, USA). He specialized in liver and kidney transplantation, and is currently specializing in engineering and regeneration of transplantable abdominal organs. His main fields of investigation are: minimal immunosuppression and clinical operational tolerance after abdominal organ transplantation; renal, pancreas, liver and intestinal bioengineering; the respinse of the immune system to bioengineered body parts. Dr. Orlando’s main achievements have been in the field of steroid-free immunosuppression, immunosuppression minimization and clinical tolerance after liver transplantation and is on the board and a regular reviewer for a number of journals. He has authored or coauthored several research papers, review articles and book chapters on liver and kidney transplantation and regenerative medicine.

Clinical Significance of Regulatory T-Cell–Related Gene Expression in Peripheral Blood After Renal Transplantation

Regulatory T cells (Tregs) have been suggested to be deeply associated with immune tolerance and long-term graft survival in transplantation. Some recipients with stable graft function (ST) could possibly minimize immunosuppression during the maintenance period. However, effective assays for assessing the suitability of patients have yet to be established. The purpose of this study was to elucidate the clinical relevance of Treg-related gene expression such as forkhead box P3 (Foxp3) in peripheral blood after renal transplantation. Several key molecules related to the function of immune cells such as Treg, including Foxp3, transforming growth factor-β, cytotoxic T-lymphocyte antigen-4, chemokine receptor 7, toll-like receptor 4, granzyme B, T-bet, GATA3, RORC, α1,2-mannosidase, and proteasome subunit β 10 were examined in the peripheral blood of 272 renal transplant recipients by quantitative real-time reverse-transcriptase polymerase chain reaction. The expression levels were compared between recipients with chronic rejection and ST. Foxp3 messenger RNA (mRNA) levels were reduced immediately after transplantation and gradually recovered. Pretransplantation levels were closely correlated with 1 year posttransplantation levels. Recipients with chronic rejection had significantly lower levels of Foxp3, chemokine receptor 7, and granzyme B mRNA, and higher levels of toll-like receptor 4 and proteasome subunit β 10 mRNA compared with those with ST, although Foxp3 was the most relevant marker. There is a possibility that monitoring mRNA expression levels of Treg-related molecules in peripheral blood might offer useful information on patient selection and early detection of rejection when immunosuppression minimization strategy is implemented in renal transplantation.

Renal Transplantation in Hepatitis C Positive Patients: A Single Centre Experience

Introduction. Hepatitis C virus (HCV) infection is an independent risk factor for renal transplantation (RTx). Immunosuppression minimization can render better quality of life to these patients. Methods. We analyzed 132 HCV-positive RTx patients (group A) transplanted under tolerance induction protocol (TIP) and compared them with 79 controls (group B) transplanted using standard triple drugs. TIP consisted of 1 donor-specific transfusion, peripheral blood stem cell infusion, portal infusion of bone marrow, and target-specific irradiation. Their immunosuppression was cyclosporin, 2 ± 1 mg/kg BW/day + prednisone, 10 mg/day. Results. TIP had no side effects. Although unequal in size, the groups were well balanced. Group A patient survival at 1, 5, and 10 years was 92.4%, 70.4%, and 63.7%, respectively, versus 75.6%, 71.7%, and 55.7% in later, and graft survival was 92.9%, 81.5%, and 79.1% versus 91.7%, 75.7%, and 67.7%, respectively. Mean serum creatinine (mg/dL) at these time periods in former was 1.38, 1.72, and 1.87, versus 1.3, 1.75, and 2.1 in later. Altered liver functions were noted in 22% patients in former versus 31% in later. Group A had lesser rejection episodes. Conclusion. RTx using TIP in HCV-positive patients is a viable option with acceptable outcome.

Transplantation tolerance: Clinical potential of regulatory T cells.

The major challenge in transplantation medicine remains long-term allograft acceptance, with preserved allograft function under minimal chronic immunosuppression. To safely achieve the goal of sustained donor-specific T and B cell non-responsiveness, research efforts are now focusing on therapies based on cell subsets with regulatory properties. In particular the transfusion of human regulatory T cells (Treg) is currently being evaluated in phase I/II clinical trials for the treatment of graft versus host disease following hematopoietic stem cell transplantation, and is also under consideration for solid organ transplantation. The purpose of this review is to recapitulate current knowledge on naturally occurring as well as induced human Treg, with emphasis on their specific phenotype, suppressive function and how these cells can be manipulated in vitro and/or in vivo for therapeutic purposes in transplantation medicine. We highlight the potential but also possible limitations of Treg-based strategies to promote long-term allograft survival. It is evident that the bench-to-beside translation of these protocols still requires further understanding of Treg biology. Nevertheless, current data already suggest that Treg therapy alone will not be sufficient and needs to be combined with other immunomodulatory approaches in order to induce allograft tolerance.

State of the art on the research for biomarkers allowing individual, tailor-made minimization of immunosuppression

In order to avoid toxic side effects by long-term immunosuppressive treatment, transplant research therefore focuses on new strategies to either induce tolerance or allow partial or complete immunosuppressive weaning whenever possible. This can be only safely achieved when guided by biomarkers reflecting the individual immune reactivity. Here we summarize the recent efforts to identify biomarkers and functional assays which allow an individualized minimization or complete weaning of immunosuppression in stable or 'operational' tolerant transplant patients, respectively. Data obtained by two main collaborative networks, 'RISET' and 'Immune Tolerance Network' have provided a better characterization of operational tolerant kidney patients. In both studies an increased numbers of B cells and a B-cell-associated peripheral gene signature were discovered. Long-term observation of tolerant liver transplant patients undergoing immunosuppressive minimization highlight the importance of surveillance or protocol biopsies. Additionally, functional assays such as IFN-γ ELISPOT or urine markers have been shown to predict long-term graft outcome. With the recent findings we have gained a better understanding of operational tolerant patients and have identified biomarkers and assays which will be very helpful when guiding partial or complete immunosuppressive minimization. For the future, collaborative efforts are needed to design and perform prospective multicenter trials to validate the identified biomarkers across different laboratories and laboratory platforms.