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Immunosuppressive Strategies (immunosuppressive + strategy)
Selected AbstractsImmunosuppression using the mTOR inhibition mechanism affects replacement of rat liver with transplanted cells,HEPATOLOGY, Issue 2 2006Yao-Ming Wu Successful grafting of tissues or cells from mismatched donors requires systemic immunosuppression. It is yet to be determined whether immunosuppressive manipulations perturb transplanted cell engraftment or proliferation. We used syngeneic and allogeneic cell transplantation assays based on F344 recipient rats lacking dipeptidyl peptidase IV enzyme activity to identify transplanted hepatocytes. Immunosuppressive drugs used were tacrolimus (a calcineurin inhibitor) and its synergistic partners, rapamycin (a regulator of the mammalian target of rapamycin [mTOR]) and mycophenolate mofetil (an inosine monophosphate dehydrogenase inhibitor). First, suitable drug doses capable of inducing long-term survival of allografted hepatocytes were identified. In pharmacologically effective doses, rapamycin enhanced cell engraftment by downregulating hepatic expression of selected inflammatory cytokines but profoundly impaired proliferation of transplanted cells, which was necessary for liver repopulation. In contrast, tacrolimus and/or mycophenolate mofetil perturbed neither transplanted cell engraftment nor their proliferation. Therefore, mTOR-dependent extracellular and intracellular mechanisms affected liver replacement with transplanted cells. In conclusion, insights into the biological effects of specific drugs on transplanted cells are critical in identifying suitable immunosuppressive strategies for cell therapy. (HEPATOLOGY 2006;44:410,419.) [source] Disengaging the IL-2 Receptor with Daclizumab Enhances IL-7,Mediated Proliferation of CD4+ and CD8+ T CellsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2009P. Monti Allograft rejection is mainly driven by the production of IL-2, which expands T cells by linking the IL-2 receptor (IL-2R) composed of three subunits: CD25, CD122 and CD132. Daclizumab, widely used in immunosuppression, is a humanized anti-CD25 antibody that disrupts IL-2 signaling by binding to CD25 and preventing the assembly of the high-affinity IL-2R. Here we show that Daclizumab, while blocking the T-cell response to IL-2, increases CD4+ and CD8+ T-cell proliferative response to the homeostatic cytokine IL-7. The IL-7R shares CD132 with the IL-2R and blocking of CD25 by Daclizumab results in the enhanced formation of the IL-7R that in turn allows IL-7 to bind more efficiently on the cell surface. The consequently increased IL-7R signaling boosts intracellular phosphorylated STAT5 and T-cell proliferation. In addition, treatment with Daclizumab delays the internalization of CD127 upon IL-7 treatment, retaining T-cell sensitivity to IL-7 for a prolonged time. This effect of Daclizumab highlights the redundancy of the cytokine system, which may influence T-cell proliferation in transplanted patients, and provides information to improve future immunosuppressive strategies. [source] Influence of Cyclooxygenase-2 (COX-2) Gene Promoter Polymorphism ,765 on Graft Loss After Renal TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2009C. Courivaud A G,C polymorphism has been identified in the human cyclooxygenase-2 (COX-2) gene promoter at position ,765 with C allele leading to a decreased promoter activity with low prostaglandin E2 (PGE2) production. PGE2 has strong immunomodulatory properties that could influence graft survival. We studied the association between this polymorphism and allograft failure in two independent cohorts of renal transplant recipients (RTRs) including a total of 603 patients. The functional effect of COX-2 gene promoter polymorphism was analyzed by measuring serum levels of PGE2. Median follow-up was 8.7 and 7.9 years for the first and second cohort, respectively. Analysis of 603 patients identified 20 CC (3.3%), 179 GC (29.7%) and 404 GG (67%) carriers. Patients with the GG genotype had significantly higher serum PGE2 concentrations than patients with the C allele. Carriers with a C allele have an independent increased risk of graft loss (hazard ratio (HR) 2.43 [95% CI 1.19,4.97], p = 0.015 for cohort 1; HR 1.72 [95% CI 0.99,3.77], p = 0.051 for cohort 2) compared to GG patients. COX-2 gene promoter polymorphism at position ,765 (G,C) is associated with a higher rate of graft loss in RTRs. Such findings may be used to influence immunosuppressive strategies and optimize patient management. [source] Skin Cancer in Organ Transplant Recipients,Where Do We Stand Today?AMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2008C. Ulrich Skin cancers are the most frequent malignancies in organ transplant recipients (OTR), with 95% being nonmelanoma skin cancers (NMSC), especially squamous (SCC) and basal cell carcinomas. Most OTR with a first SCC subsequently develop multiple NMSC within 5 years, highlighting the concept of ,field cancerization', and are also at high risk for noncutaneous cancers. In order to reduce the tumor burden in these patients, their management requires an interdisciplinary approach including revision of immunosuppression, new dermatological treatments and adequate education about photoprotection in specialized dermatology clinics for OTR. Whereas surgery remains the gold-standard therapy for NMSC, noninvasive methods have shown promising results to treat superficial keratoses and subclinical lesions on large body areas. Although the threshold of skin cancer necessitating revision of immunosuppression is debated, this measure should be envisaged at the occurrence of the first SCC, or in case of multiple non-SCC NMSC. While the role of immunosuppressants in the occurrence of NMSC is widely recognized, the best immunosuppressive strategies remain to be defined. Presently, randomized prospective studies assess the burden of new skin tumors, as well as graft and patient survival, in patients with one or several NMSC after the introduction of mTOR (mammalian target of rapamycin) inhibitors. [source] Obesity following kidney transplantation and steroid avoidance immunosuppressionCLINICAL TRANSPLANTATION, Issue 3 2008Eric A. Elster Abstract:, Obesity is an important co-morbidity within end-stage renal disease (ESRD) and renal transplant populations. Previous studies have suggested that chronic corticosteroids result in increased body weight post-transplant. With the recent adoption of steroid-sparing immunosuppressive strategies, we evaluated the effect of these strategies on body mass index (BMI) after renal transplantation. We examined 95 renal transplant recipients enrolled in National Institutes of Health clinical transplant trials over the past three yr who received either lymphocyte depletion-based steroid sparing or traditional immunosuppressive therapy that included steroids for maintenance immunosuppression. Recipients were overweight prior to transplant and no significant differences existed in pre-transplant BMI among treatment groups. Regardless of therapy, BMI increased post-transplant in all recipients. The BMI increase consisted of an average weight gain of 5.01 ± 7.12 kg (mean, SD) post-transplant. Additionally, in a number of recipients placed on maintenance steroids, subsequent withdrawal at a mean of 100 d post-transplant had no impact on weight gain. Thus, body weight and BMI increase following kidney transplantation, even in the absence of steroids. Thus, patients gain weight after renal transplantation regardless of the treatment strategy. Steroid avoidance alone does not reduce risk factors associated with obesity in our patient population. [source] Impact of cyclosporine 2-h level and mycophenolate mofetil dose on clinical outcomes in de novo heart transplant patients receiving anti-thymocyte globulin inductionCLINICAL TRANSPLANTATION, Issue 2 2003Marcelo Cantarovich Abstract: Background: Cyclosporine (CsA) 2-h post-dose level (C2) correlates better than trough levels (C0) with the area under the curve. We evaluated the clinical impact of C2 and mycophenolate mofetil (MMF) dose in adult heart transplant patients receiving anti-thymocyte globulin (ATG) induction. Methods: Two immunosuppressive strategies were sequentially evaluated. In Group 1 (13 patients), simultaneous C0/C2 (ng/mL) were analyzed. CsA dose monitoring was initially based on C0 : <3 months: 200,300, 4,6 months: 150,250, 6,9 months: 100,200, and on C2 thereafter (as in Group 2). In Group 2 (nine patients), C2 monitoring was implemented: <3 months: 600,800, 4,6 months: 500,700, >6 months: 400,600. All patients received ATG induction, corticosteroids, and MMF (1.0 g b.i.d. in Group 1 and 1.5 g b.i.d. in Group 2). Results: Patients in Group 2 received higher MMF doses during the first trimester. C2 at 1, 3, 6, 12, 24, and 36 months was, respectively, 1199 ± 476, 1202 ± 587, 999 ± 467, 664 ± 203, 593 ± 208, and 561 ± 147 in Group 1, and 809 ± 160 (p = 0.02), 644 ± 178 (p = 0.003), 664 ± 169 (p = 0.02), 616 ± 221, 464 ± 234, and 451 ± 165 in Group 2. The incidence of acute rejection (grade ,3A) at 6, 12, 24, and 36 months was, respectively, 38.5, 38.5, 46, and 54% in Group 1, and 11, 44, 56, and 56% in Group 2 (p = NS). At 3 months, the creatinine clearance was 25% lower in Group 1. Thereafter, renal function remained stable in both groups. Conclusion: Our results suggest that heart transplant patients receiving ATG induction may experience similar outcomes with either a higher C2 and a lower MMF dose or a lower C2 and a higher MMF dose. These results could be considered to design prospective studies to optimize C2 monitoring, to reduce the incidence of acute rejection without increasing the risk of renal dysfunction. [source] Mycophenolate mofetil without antibody induction in cadaver vs. living donor pediatric renal transplantationPEDIATRIC TRANSPLANTATION, Issue 2 2003O. Ojogho Abstract: Mycophenolate mofetil (MMF) is a new immunosuppressive agent that blocks de novo purine synthesis in T and B lymphocytes via a potent selective inhibition of inosine monophosphate dehydrogenase. MMF has been shown to significantly reduce the incidence of acute rejection in both adult and pediatric renal transplantation. The impact of MMF on routine antibody induction therapy in pediatric renal transplantation has not been defined. Remarkably, a recent North American Pediatric Transplant Cooperative Study concluded that T-cell antibody induction therapy was deleterious for patients who received MMF. Our study examines the use of MMF in an evolving immunosuppressive strategy to avoid antibody induction in both living (LD) and cadaver (CAD) donor pediatric renal transplantation. We retrospectively analyzed the records of 43 pediatric renal transplants that received MMF-based triple therapy without antibody induction therapy between November 1996 and April 2000. We compared CAD (n = 17) with LD (n = 26). The two groups were similar demographically except that CAD had significantly younger donors than LD, 26.1 ± 13.7 vs. 36.2 ± 9.2 yr (p = 0.006). All the patients received MMF at 600 mg/m2/b.i.d. (maximum dose of 2 g/d) and prednisone with cyclosporine (86%) or tacrolimus (14%). Mean follow-up was >36 months for each group. Acute rejection rate at 6 months was 11.8% (CAD) vs. 15.4% (LD) (p = 0.999) and at 1 yr was 23.5% (CAD) vs. 26.9% (LD) (p = 0.999). Mean estimated glomerular filtration rate (ml/min/1.73 m2) at 6 months was 73.3 ± 15.3 (CAD) vs. 87.6 ± 24.2 (LD) (p = 0.068). Patient survival at 1, 2, and 3 yr was 100, 100, and 100% for CAD vs. 100, 96, and 96% for LD, respectively. Graft survival at 1, 2, and 3 yr was 100, 100, and 94% for CAD vs. 96, 88, and 71% for LD, respectively. Graft loss in CAD was because of chronic rejection (n = 2) while in LD it was because of non-compliance (n = 6), post-transplant lymphoproliferative disorder (n = 1), and sepsis (n = 1). In conclusion, MMF without antibody induction in both CAD and LD pediatric renal transplantation provides statistically similar and effective prophylaxis against acute rejection at 6 months and 1 yr post-transplant. The short-term patient and graft survival rates are excellent, however, non-compliance remains a serious challenge to long-term graft survival. Additional controlled studies are needed to define the role of MMF without antibody induction therapy in pediatric renal transplantation. [source] Immunoprophylaxis with Basiliximab Compared with Antithymocyte Globulin in Renal Transplant Patients Receiving MMF-containing Triple TherapyAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2002Yvon Lebranchu Acute graft rejection remains a major problem in renal transplant recipients, and there is no consensus on the optimal immunosuppressive strategy. Immunoprophylaxis with Thymoglobulin® or basiliximab has significantly reduced the incidence of acute rejection episodes and graft loss following kidney transplantation. This open, randomized, multicenter study investigated the efficacy and tolerability of basiliximab (20 mg day 0, day 4) plus early cyclosporine from day 0 (n = 50) compared with Thymoglobulin® plus delayed cyclosporine (n = 50) in adult kidney transplant patients. In addition, all patients received steroids and mycophenolate mofetil (MMF) at standard doses from day 0. Patient and graft survival rates at 12 months were 98 and 94% in the basiliximab group, respectively, compared with 100 and 96% in the Thymoglobulin® group. The incidences of biopsy-confirmed acute rejection (8.0% in each group) and treatment failure (14% in the basiliximab group vs. 8% in the Thymoglobulin group) were comparable in the two groups. There was a nonsignificant tendency to more dialysis (14 vs. 6%), and fewer cytomegalovirus (CMV) infections (p =,0.005) in the basiliximab group, but the percentage of clinical CMV was not different between the two groups (6 vs. 12%). Both strategies give excellent results, despite the differences in patterns, in nonhyperimmunized patients receiving their first cadaveric renal allograft. [source] Therapeutic drug monitoring for everolimus in kidney transplantation using 12-month exposure, efficacy, and safety dataCLINICAL TRANSPLANTATION, Issue 2 2005Marc I Lorber Abstract:, The aims of the current study were to determine whether therapeutic drug monitoring (TDM) might benefit kidney transplant recipients receiving everolimus, and to establish dosage recommendations when everolimus is used in combination with cyclosporine and corticosteroids. The analysis was based on data from 779 patients enrolled in two 12-month trials. Everolimus trough concentrations ,3 ng/mL were associated with a reduced incidence in biopsy-proven acute rejection (BPAR) in the first month (p = 0.0001) and the first 6 months (p = 0.0001), and reduced graft loss compared with lower concentrations (4% vs. 20%, respectively). By contrast, cyclosporine in the standard concentration range had no impact on BPAR within the same timeframes. Most patients receiving everolimus 1.5 or 3 mg/d achieved trough concentrations above the therapeutic threshold of 3 ng/mL, regardless of reductions in cyclosporine dose. TDM simulation showed that just two dose adjustments would achieve median everolimus trough values ,3 ng/mL in 95% of patients during the first 6 months. This investigation indicates that improved efficacy is likely when TDM is considered as an integral component of the immunosuppressive strategy of everolimus. [source] | ||||||||||