Cyclosporine Prolongs Delayed Graft Function in Kidney Transplantation: Are Rabbit Anti-Human Thymocyte Globulins the Answer?

Alemtuzumab versus antithymocyte globulin induction therapies in kidney transplantation patients: A systematic review and meta-analysis of randomized controlled trials

Alemtuzumab (ALEM) is widely used as an induction therapy for organ transplantation, and numerous randomized controlled trials (RCTs) have been published to evaluate its efficacy and safety in kidney transplantation as compared with antithymocyte globulin (ATG). The purpose of this study was to compare the benefits and safety of ALEM with those of ATG for induction therapy.A systematic literature search in three electronic databases, including PubMed, EmBase, and Cochrane Library, since inception through October 2016, was conducted to identify potential RCTs for inclusion. Trials that investigated the risk of biopsy-proven acute rejection (BPAR), mortality, graft failure, delayed graft function (DGF), chronic allograft nephropathy (CAN), infections, cytomegalovirus (CMV) infections, new-onset diabetes mellitus after transplant (NODAT), and granulocyte colony stimulation factor (GCSF) use in kidney transplant recipients who received ALEM or ATG as an induction therapy were included. Relative risk (RR) and 95% confidence intervals (CIs) were calculated using a random-effects model.Six RCTs involving 446 kidney transplantation patients were included in this meta-analysis. The effects of ALEM therapy were not significantly different from those of ATG therapy, including the incidence of BPAR (RR: 0.77; 95% CI: 0.51-1.18; P = .229), mortality (RR: 0.64; 95% CI: 0.30-1.39; P = .263), graft failure (RR: 0.81; 95% CI: 0.49-1.33; P = .411), DGF (RR: 1.00; 95% CI: 0.60-1.67; P = .999), CAN (RR: 1.42; 95% CI: 0.44-4.57; P = .556), infections (RR: 1.00; 95% CI: 0.74-1.35; P = .989), CMV infections (RR: 0.70; 95% CI: 0.38-1.30; P = .263), NODAT (RR: 0.50; 95% CI: 0.18-1.36; P = .174), and GCSF use (RR: 1.16; 95% CI: 0.81-1.66; P = .413). Sensitivity analyses were consistent with the overall analysis for all effects except CAN, suggesting that the risk of CAN might be higher with ALEM therapy than ATG therapy (RR: 2.45; 95% CI: 1.02-5.94; P = .046).The findings of this study suggest that the beneficial effects of ALEM therapy are greater than those of ATG therapy in kidney transplantation patients; however, the effects were not statistically significant because of the limited number of trials. Further large-scale RCTs are needed to verify the treatment effects of ALEM.

Immunosuppression for in vivo research: state-of-the-art protocols and experimental approaches

Almost every experimental treatment strategy using non-autologous cell, tissue or organ transplantation is tested in small and large animal models before clinical translation. Because these strategies require immunosuppression in most cases, immunosuppressive protocols are a key element in transplantation experiments. However, standard immunosuppressive protocols are often applied without detailed knowledge regarding their efficacy within the particular experimental setting and in the chosen model species. Optimization of such protocols is pertinent to the translation of experimental results to human patients and thus warrants further investigation. This review summarizes current knowledge regarding immunosuppressive drug classes as well as their dosages and application regimens with consideration of species-specific drug metabolization and side effects. It also summarizes contemporary knowledge of novel immunomodulatory strategies, such as the use of mesenchymal stem cells or antibodies. Thus, this review is intended to serve as a state-of-the-art compendium for researchers to refine applied experimental immunosuppression and immunomodulation strategies to enhance the predictive value of preclinical transplantation studies.

Prediction, prevention, and management of delayed graft function: where are we now?

Delayed graft function (DGF) remains a major barrier to improved outcomes after kidney transplantation. High-risk transplant recipients can be identified, but no definitive prediction model exists. Novel biomarkers to predict DGF in the first hours post-transplant, such as neutrophil gelatinase-associated lipocalin (NGAL), are under investigation. Donor management to minimize the profound physiological consequences of brain death is highly complex. A hormonal resuscitation package to manage the catecholamine "storm" that follows brain death is recommended. Donor pretreatment with dopamine prior to procurement lowers the rate of DGF. Hypothermic machine perfusion may offer a significant reduction in the rate of DGF vs simple cold storage, but costs need to be evaluated. Surgically, reducing warm ischemia time may be advantageous. Research into recipient preconditioning options has so far not generated clinically helpful interventions. Diagnostic criteria for DGF vary, but requirement for dialysis and/or persistent high serum creatinine is likely to remain key to diagnosis until current work on early biomarkers has progressed further. Management centers on close monitoring of graft (non)function and physiological parameters. With so many unanswered questions, substantial reductions in the toll of DGF in the near future seem unlikely but concentrated research on many levels offers long-term promise.

Ischemia and reperfusion injury in renal transplantation: hemodynamic and immunological paradigms

Ischemia and reperfusion injury is an inevitable event in renal transplantation. The most important consequences are delayed graft function, longer length of stay, higher hospital costs, high risk of acute rejection, and negative impact of long-term follow-up. Currently, many factors are involved in their pathophysiology and could be classified into two different paradigms for education purposes: hemodynamic and immune. The hemodynamic paradigm is described as the reduction of oxygen delivery due to blood flow interruption, involving many hormone systems, and oxygen-free radicals produced after reperfusion. The immune paradigm has been recently described and involves immune system cells, especially T cells, with a central role in this injury. According to these concepts, new strategies to prevent ischemia and reperfusion injury have been studied, particularly the more physiological forms of storing the kidney, such as the pump machine and the use of antilymphocyte antibody therapy before reperfusion. Pump machine perfusion reduces delayed graft function prevalence and length of stay at hospital, and increases long-term graft survival. The use of antilymphocyte antibody therapy before reperfusion, such as Thymoglobulin™, can reduce the prevalence of delayed graft function and chronic graft dysfunction.

Low-dose RATG with or without basiliximab in renal transplantation: a matched-cohort observational study

BACKGROUND/AIMS

In renal transplantation, peri-operative low-dose rabbit-antithymocyte-globulin (RATG) plus basiliximab induction prevented acute allograft rejection more effectively than post-operative RATG plus basiliximab induction. We investigated the specific antirejection contribution of basiliximab in this context.

METHODS

This single-center, observational, matched-cohort study evaluated allograft rejections (primary outcome), steroid exposure and side effects, GFR (iohexol plasma clearance) and treatment costs in 16 deceased-donor renal transplant recipients induced with RATG (0.5 mg/kg/day) and 32 age-, gender- and treatment-matched reference-patients given RATG plus basiliximab (20 mg on days 0 and 4).

RESULTS

Induction was well tolerated. At 18 months, 8 patients (50%) vs. 3 reference-patients (9.4%) rejected the graft [HR (95% CI): 6.53 (1.73-24.70), p = 0.006]. Difference was significant (p < 0.01) even after adjusting for recipient/donor age and gender, cold ischemia time and HLA mismatches. There were 1 antibody-mediated rejection and 2 moderate cellular rejections in patients vs. none in reference-patients (p = 0.032). The median (interquartile range) prednisone cumulative dose was remarkably higher in patients than reference-patients [4.78 (1.12-6.10) vs. 0.19 (0.18-3.81) grams, p = 0.002]. Three patients vs. 24 reference-patients were off-steroid at study end (p < 0.001). Three patients vs. no reference-patient developed new-onset diabetes (p = 0.003). Both inductions similarly depleted B-cells. Outcomes of AZA- vs. MMF-treated participants were similar. GFR was similar in all groups. Compared to MMF, AZA therapy saved ≈ EUR 2,500/year and by month 14.3 post-transplant compensated basiliximab costs.

CONCLUSION

In renal transplantation, basiliximab plus peri-operative low-dose RATG more efficiently prevented allograft rejection than RATG monotherapy, and minimized steroid exposure and toxicity. AZA- vs MMF-based maintenance immunosuppression largely compensated the extra costs of basiliximab.

Immunotherapy for acute kidney injury

Acute renal failure, now referred to as acute kidney injury, is a common and clinically important problem. Acute kidney injury frequently occurs as a result of acute tubular necrosis (ATN), which is often caused by a reduction in systemic blood pressure or renal blood flow (e.g., as observed in severe sepsis or during renal transplantation). The disease course in ATN is variable, including prolonged dialysis-dependence and chronic renal dysfunction, but there is currently no specific therapy for ATN. There is increasing evidence that the inflammatory response in ATN significantly contributes to disease severity and outcome. In this review, we summarize recent developments in the understanding of how the immune system responds to dying cells, and the relevance of these discoveries to ATN. In particular, NLRP3 inflammasome activation and IL-1β-mediated neutrophil recruitment are likely to play a key role and may provide novel therapeutic targets for immunotherapy in ATN.

Perioperative Minimal Induction Therapy: A Further Step toward More Effective Immunosuppression in Transplantation

Dual induction with low doses of rabbit anti-human thymoglobulin (RATG) and basiliximab effectively and safely prevented allograft rejection in high-risk renal transplant recipients. To assess whether treatment timing affects efficacy and tolerability, in this single-center, matched-cohort study, we compared posttransplant outcomes in 25 patients and 50 gender-, age-, and treatment-matched reference patients induced with the same course of 7 daily RATG infusions (0.5 mg/kg/day) started before or after engraftment, respectively. All subjects received basiliximab (20 mg) before and 4 days after transplantation, withdrew steroids within 6 days after surgery, and were maintained on steroid-free immunosuppression with cyclosporine and mycophenolate mofetil or azathioprine. Over 12 months after transplant, 1 patient (4%) and 13 reference patients (26%) had acute rejection episodes. One patient and 5 reference-patients required dialysis therapy because of delayed graft function. In all patients circulating CD4+ and CD8+ T lymphocytes were fully depleted before engraftment. Both treatments were well tolerated. In kidney transplantation, perioperative RATG infusion enhances the protective effect of low-dose RATG and basiliximab induction against graft rejection and delayed function, possibly because of more effective inhibition of early interactions between circulating T cells and graft antigens.

Mycophenolate mofetil modifies kidney tubular injury and Foxp3+ regulatory T cell trafficking during recovery from experimental ischemia-reperfusion

Lymphocytes participate in the early pathogenesis of ischemia-reperfusion injury (IRI) in kidney; however, their role during repair is largely unknown. Recent data have shown that Foxp3(+) regulatory T cells (Tregs) traffic into kidney during healing from IRI and directly participate in repair. Since lymphocyte-targeting therapy is currently administered to prevent rejection during recovery from IRI in renal transplants, we hypothesized that mycophenolate mofetil (MMF) would alter Treg trafficking and kidney repair. C57BL/6J and T cell deficient mice underwent unilateral clamping of renal pedicle for 45 min, followed by reperfusion, and were sacrificed at day 10. Mice were treated with saline (C) or MMF (100mg/kg) i.p. daily starting at day 2 until sacrifice (n=5-12/group). MMF worsened kidney tubular damage compared to C at 10 days (cortex and outer medulla: p<0.05) in wild-type mice; tubular apoptotic index was increased in cortex in MMF group as well (p=0.01). MMF reduced the total number of kidney-infiltrating mononuclear cells (p<0.001 versus C) and the percentages of TCRbeta(+)CD4(+) and TCRbeta(+)CD8(+) T cells (p<0.01), but not natural killer (NK), NKT or B lymphocytes. MMF specifically reduced kidney Foxp3(+) Tregs (0.82+/-0.11% versus 1.75+/-0.17%, p<0.05). Tubular proliferative index and tissue levels of basic FGF were increased in MMF group (p<0.05), IL-10 and IL-6 were decreased (p<0.05). To evaluate if MMF effect occurred through non-lymphocytic cells, T cell deficient mice were treated with MMF. Tubular injury in T cell deficient mice was not affected by MMF treatment, though MMF-treated animals had increased VEGF and decreased PDGF-BB protein tissue levels compared to controls (p<0.05). Thus, MMF modifies the structural, epithelial proliferative and inflammatory response during healing, likely through effects on T cells and possibly Tregs. Kidney repair after IRI can be altered by agents that target lymphocytes.

[Delayed graft function]

Delayed return to kidney function after transplantation is characterized essentially by acute ischemic tubular necrosis. It remains frequent and has no curative treatment. However, an induction treatment of antilymphocyte serum may reduce the delay in recuperation. In patients with delayed function, the maintenance immunosuppressive treatment should take into account the excessive risk of acute rejection over the short term and the more rapid deterioration of renal function over the long term. This means that biopsies to screen for acute rejection should be done systematically before the end of the 3rd month and anticalcineurin toxicity-sparing treatment should be considered, replacing anticalcineurins immediately with belatacept or after the 3-month acute period with proliferation signal inhibitors, if the kidney histology tests permit. In all cases, the classical measures of kidney protection remain indispensable.

Induction immunosuppressive therapy in renal transplantation: does basiliximab make the difference?

The optimal prophylactic induction immunosuppressive therapy to prevent renal transplant rejection remains controversial. Recently, basiliximab efficiency has been reported in several studies. We sought to evaluate the efficiency of induction immunosuppressive therapy with basiliximab in renal transplantation in our unit based upon the acute rejection rate, patient and graft survivals, first hospital admission length, and incidence of infectious or malignant complications during 4 years of follow-up. We retrospectively evaluated the outcome of two groups of renal transplant recipients treated with triple immunosuppressive therapy (cyclosporine, mycophenolate mofetil, and prednisolone) without (group 1, 149 patients) or with (group 2, 104 patients) induction immunosuppression with basiliximab. The two groups did not differ in demographic characteristics, number of hypersensitized patients, cold ischemia time, or donor age. The group receiving basiliximab displayed a significantly lower acute rejection rate (7.6% vs 24%, P = .001) and shorter first hospital admission (14.4 +/- 8 vs 19.5 +/- 11 days). There was no difference in graft or patient survival, death due to sepsis, or incidence of posttransplant malignancies. Although there was no difference in graft or patient survival, immunosuppressive induction therapy with basiliximab yielded a significant reduction in the acute rejection rate.

Renal function with delayed or immediate cyclosporine microemulsion in combination with enteric-coated mycophenolate sodium and steroids: results of follow up to 30 months post-transplant

BACKGROUND

In the multicenter, open-label Myriade study, renal transplant patients were randomized to early cyclosporine microemulsion (CsA-ME, day 0) or delayed CsA-ME (day 6) with enteric-coated mycophenolate sodium (EC-MPS), steroids and interleukin-2 receptor induction. One-yr results have been published previously. We now report the results of an extension study in which patients were followed up for a period of three yr post-transplant.

METHODS

All patients completing the one-yr core study on-treatment were eligible to enter the extension study.

RESULTS

Of the 203 patients, 153 completed the core trial on-treatment; 144 (94%) entered the extension study with a minimum follow-up of one yr (73 early CsA-ME, 71 delayed CsA-ME). In 75% of patients receiving EC-MPS during the extension, the recommended dose was administered (1440 mg/d). Median creatinine clearance remained constant (57 mL/min) at 12, 24 and 30 months post-transplant and was similar in the early and delayed CsA-ME groups as well as in subpopulations with or without delayed graft function. One patient in the early CsA-ME group died. No grafts were lost. The incidence of BPAR from time of transplant to the end of the extension study was 17% (24/139). Seven patients (5%) discontinued the extension study prematurely because of adverse events.

CONCLUSION

These results suggest that a regimen of CsA-ME, EC-MPS and steroids results in excellent survival rates with stable renal function over a mean follow-up of 30 months. Immediate introduction of CsA-ME has no deleterious effect on long-term renal function, even among patients with delayed graft function.

Basiliximab combined with low-dose rabbit anti-human thymocyte globulin: a possible further step toward effective and minimally toxic T cell-targeted therapy in kidney transplantation

In high-risk kidney transplant recipients, induction therapy with rabbit anti-human thymocyte globulin (RATG) reduces the risk for acute rejection but is associated with significant toxicity, opportunistic infections, and cancer. Using reduced doses of RATG combined with anti-IL-2 antibodies may achieve the same antirejection activity of standard-dose RATG but with a better safety profile. This randomized, open-label study compared the efficacy, tolerability, and costs of low-dose RATG (0.5 mg/kg per d) plus basiliximab (20 mg 4 d apart) versus standard-dose RATG (2 mg/kg per d) in 33 consecutive high-risk renal transplant recipients (living-related transplant recipients, sensitized patients or patients who received another transplant, and patients with delayed graft function) over 6 mo of follow-up. All patients received concomitant therapy with steroids, cyclosporin A, and azathioprine or mycophenolate mofetil. Seventeen patients received low-dose RATG plus basiliximab, and 16 received standard-dose RATG. Patient (100 versus 100%) and graft (94 versus 100%) survival were comparable in the two groups, but the incidence of fever (17.6 versus 56.5%; P = 0.01), leukopenia (23.5 versus 56.3%; P < 0.05), anemia (29.4 versus 62.5%; P < 0.05), cytomegalovirus reactivations (17.6 versus 56.5%; P = 0.01), the number of transfused units (0.5 +/- 0.9 versus 2.0 +/- 2.4; P < 0.001), and treatment costs (3652 +/- 704 versus 5400 +/- 1960 euro; P = 0.001) were lower with low-dose RATG plus basiliximab than with standard-dose RATG. There was one episode of biopsy-proven acute rejection on low-dose RATG plus basiliximab, and there were two on standard-dose RATG. In renal transplantation, induction therapy with basiliximab plus low-dose RATG effectively prevents acute rejection and is safer and more cost-effective than induction with standard-dose RATG.