Interleukin-2 Receptor Antagonists in Liver Transplantation: A Meta-analysis of Randomized Trials

Secondary immunodeficiencies and infectious considerations of biologic immunomodulatory therapies

Biologic immunomodulatory medications have rapidly expanded in the previous decades, providing new treatment options for individuals with a spectrum of oncologic, allergic, rheumatologic, and neurologic conditions. Biologic therapies alter immune function and can impair key host defense mechanisms, resulting in secondary immunodeficiency and increased infectious risks. Biologic medications can increase general risk for upper respiratory tract infections but can also be associated with unique infectious risks owing to distinct mechanisms of action. With the widespread use of these medications, providers in every area of medicine will likely care for individuals receiving biologic therapies and understanding their potential infectious complications can help mitigate these risks. This practical review discusses the infectious implications of biologics by class of medication and provides recommendations regarding the examination and screening both before therapy initiation and while the patient is receiving the medication. With this knowledge and background, providers can reduce risk whereas patients receive the treatment benefits of these biologic medications.

T-cell specific antibody induction versus corticosteroid induction immunosuppression for liver transplant recipients: a meta-analysis

Corticosteroids remain the mainstay of immunosuppression for liver transplant recipients despite several serious complications including infection, hepatitis C virus (HCV) recurrence, diabetes mellitus (DM), and hypertension. We attempted to compare the safety and efficacy of T-cell specific antibody induction with complete corticosteroid avoidance. We searched MEDLINE, EMBASE, and Cochrane central library. Randomized controlled trials comparing T-cell specific antibody induction with corticosteroid induction immunosuppression were included. Our primary outcome was the incidence of biopsy-proven acute rejection. Eleven trials involving 1683 patients were included. The incidence of acute rejection was not significantly different between the antibody and steroid induction groups (risk ratio [RR] 0.85, 95% confidence interval [CI] 0.72, 1.01, P = 0.06, I2 = 0%). However, T-cell specific antibody induction significantly reduced the risk of cytomegalovirus infection (RR 0.48, 95% CI 0.33, 0.70, P = 0.0002, I2 = 3%), HCV recurrence (RR 0.89, 95% CI 0.80, 0.99, P = 0.03, I2 = 0%), DM (RR 0.41, 95% CI 0.32, 0.54, P < 0.0001, I2 = 0%) and hypertension (RR 0.71, 95% CI 0.55, 0.90, P = 0.005, I2 = 35%). Trial sequential analysis for acute rejection showed that the cumulative z-curve did not cross the Trial sequential boundary and the required information size was not reached. T-cell specific antibody induction compared to corticosteroid induction seems to significantly reduce opportunistic infections including cytomegalovirus infection and HCV recurrence and metabolic complications including DM and hypertension. However, given the insufficient study power, low quality of evidence, and heterogeneous immunosuppressive regimens, our results should be cautiously appreciated.

Impact of Induction Immunosuppression Strategies in Simultaneous Liver/Kidney Transplantation

BACKGROUND

There is scant data on the use of induction immunosuppression for simultaneous liver/kidney transplantation (SLKT).

METHODS

We analyzed the Organ Procurement and Transplant Network registry from 1996 to 2016 to compare outcomes of SLKT, based on induction immunosuppression.

RESULTS

Of 5172 patients, 941 (18%) received T-cell depletion induction, 1635 (32%) received interleukin 2 receptor antagonist (IL2-RA), and 2596 (50%) received no induction (NI). At 5 years, patient survivals were 68% in the T-cell group, 74% in the IL2-RA group, and 71% in the NI group (P = 0.0006). Five-year liver and kidney allograft survivals were 67% and 64% in the T-cell group, 73% and 70% in the IL2-RA group, and 70% and 68% in the NI group (P = 0.001 and 0.003), respectively. On multivariate analysis, the type of induction had no impact on patient or allograft survival. Maintenance steroids and calcineurin inhibitors (CNIs) at discharge were associated with improved patient and graft survival (steroids: patient survival hazard ratio [HR] 0.37 [0.27-0.52], liver survival HR 0.43 [0.31-0.59], kidney survival HR 0.46 [0.34-0.63]; P < 0.0001, CNI: patient survival HR 0.3 [0.21-0.43], liver survival HR 0.3 [0.2-0.44], kidney survival HR 0.4 [0.26-0.59]; P < 0.0001). CNI maintenance in patients who received T-cell induction was associated with decreased patient, liver, and kidney allograft survivals (respective HR: 1.4 [1.1, 1.8]; 1.5 [1.1, 1.9]; 1.3 [1.08, 1.7]; P < 0.05) CONCLUSION.: Induction immunosuppression had no impact on patient and allograft survival in SLKT, while maintenance steroids and CNI were associated with improved patient and graft survivals. Given the inherent limitations of a registry analysis, these findings should be interpreted with caution.

Efficacy and safety of basiliximab as initial immunosuppression in liver transplantation: A single center study

INTRODUCTION AND AIM

The interleukin-2 receptor antagonist; basiliximab is used to allow delayed introduction of Calcineurin inhibitors (CNI) after liver transplantation and thus delay their renal insult. However, there is only little evidence for the safety and the efficacy of this regimen. This study aimed to evaluate the effectiveness and safety of basiliximab induction in liver transplantation.

MATERIALS AND METHODS

This study included 89 patients who were classified into two groups: standard triple immunosuppression (IS) regimen of steroid, tacrolimus (TAC) and mycophenolate mofetil (MMF) (n = 47) and induction IS regimen of basiliximab, low dose steroids and MMF with delayed introduction of CNI (n = 42). All patients were followed after liver transplantation for at least six months or until death.

RESULTS

There were no significant differences in patient survival, graft dysfunction, infection rate or type, or wound healing between both groups. The acute rejection rate was equivalent in both groups. Renal dysfunction in the first six months post-transplant was less in the basiliximab group in comparison to the other group (7.1% and 19.1% respectively).

CONCLUSION

Basiliximab-induced IS protocol is a safe regimen that reduces medium-term renal dysfunction and achieves similar survival without increasing the acute rejection or infection rate in liver transplantation recipients.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Lack of Benefit and Potential Harm of Induction Therapy in Simultaneous Liver-Kidney Transplants

The number of simultaneous liver-kidney transplantations (SLKTs) and use of induction therapy for SLKT have increased recently, without much published evidence, especially in the context of maintenance immunosuppression containing tacrolimus (TAC) and mycophenolic acid (MPA). We queried the Organ Procurement and Transplant Network registry for SLKT recipients maintained on TAC/MPA at discharge in the United States for 2002-2016. The cohort was divided into 3 groups on the basis of induction type: rabbit antithymocyte globulin (r-ATG; n = 831), interleukin 2 receptor antagonist (IL2RA; n = 1558), and no induction (n = 2333). Primary outcomes were posttransplant all-cause mortality and acute rejection rates in kidney and liver allografts at 12 months. Survival rates were analyzed by the Kaplan-Meier method. A propensity score analysis was used to control potential selection bias. Multivariate inverse probability weighted Cox proportional hazard and logistic regression models were used to estimate the hazard ratios (HRs) and odds ratios. Among SLKT recipients, survival estimates at 3 years were lower for recipients receiving r-ATG (P = 0.05). Compared with no induction, the multivariate analyses showed an increased mortality risk with r-ATG (HR, 1.29; 95% confidence interval [CI], 1.10-1.52; P = 0.002) and no difference in acute liver or kidney rejection rates at 12 months across all induction categories. No difference in outcomes was noted with IL2RA induction over the no induction category. In conclusion, there appears to be no survival benefit nor reduction in rejection rates for SLKT recipients who receive induction therapy, and r-ATG appears to increase mortality risk compared with no induction.

Hepatocellular cancer and recurrence after liver transplantation: what about the impact of immunosuppression?

Liver transplantation (LT) has originally been designed to treat hepatobiliary malignancies. The initial results of LT for hepatocellular cancer (HCC) were, however, dismal this mainly due to the poor patient selection procedure. Better surgical and perioperative care and, especially, the refinement of selection criteria led to a major improvement of results, making HCC nowadays (again!) one of the leading indications for LT. This evolution is clearly shown by the innumerable reports aiming to further extend inclusion criteria for LT in HCC patients. Nonetheless, the vast majority of papers only deals with morphologic (tumour diameter and number) and (only recently) biologic (tumour markers and response to locoregional treatment) parameters to do so. Curiously enough, the role of both the immune competent state of the recipient as well as the impact of both immunosuppression (IS) type and load has been very poorly addressed in this context, even if it has been shown for a long time, based on both basic and clinical research, that they all play a key role in the outcome of any oncologic treatment and in the development of de novo as well as recurrent tumours. This chapter aims to give, after a short introductive note about the currently used inclusion criteria of HCC patients for LT and about the role of IS in carcinogenesis, a comprehensive overview of the actual literature related to the impact of different immunosuppressive drugs and schemes on outcome of LT in HCC recipients. Unfortunately, up to now solid conclusions cannot be drawn due to the lack of high-level evidence studies caused by the heterogeneity of the studied patient cohorts and the lack of prospectively designed and randomized studies. Based on long-term personal experience with immunosuppressive handling in LT some proposals for further clinical research and practice are put forward. The strategy of curtailing and minimising IS should be explored in the growing field of transplant oncology taking thereby into account the immunological privilege of the liver allograft. These strategies will become more and more compelling when further extending the indications in which adjuvant chemotherapy will probably become an inherent part of the therapeutic scheme of HCC liver recipients.

Anti-interleukin-2 receptor antibodies for the prevention of rejection in liver transplant recipients: a systematic review and meta-analysis

BACKGROUND

Antibody induction therapy aims at preventing acute cellular rejection by reducing T-cell proliferation and activation. We evaluated the efficacy and side effects of two anti-interleukin-2 receptor antibodies (IL2RAs), basiliximab and daclizumab, for prevention of liver transplant rejection in adult patients.

METHODS

Randomized controlled trials (RCTs) on basiliximab or daclizumab were identified by searching multiple databases and reference lists published up to July, 2015. Endpoints included acute rejection events and mortality rates. Risk ratio (RR) and 95% confidence interval (CI) were calculated and pooled for a meta-analysis.

RESULTS

Patients treated with IL2RA-based therapy were less likely to suffer acute rejection compared to control group (steroid or steroid-free). Patients in all groups had similar mortality rate. In the subgroup analysis, basiliximab and daclizumab-based therapies did not reduced acute rejection rate. No significant difference was found in mortality rate between both types of IL-2RA treatment groups and control groups. In the subgroup analysis regarding experimental design, no significant difference in the acute rejection and mortality rates were found between "steroid plus IL2RA versus steroid" and "IL2RA versus steroid" groups.

CONCLUSION

IL2RA-based induction therapy reduces rate of acute rejection events but does not reduce mortality. However, optimal regimen relating to IL2RA-based induction therapy remains undetermined. KEY MESSAGES IL2RA-based induction therapy was effective in reduction of acute rejection events but it did not reduce mortality rate. Basiliximab-based induction therapy might be more effective than daclizumab-based induction therapy in reduction of acute rejection. No significant difference in acute rejection and mortality rate was found between types of IL2RAs or IL2RA-steroid combined therapy.

Basiliximab application on liver recipients: a meta-analysis of randomized controlled trials

BACKGROUND

The benefits of the application of basiliximab induction therapy in liver transplantation are not clear. The present meta-analysis was to evaluate the pros and cons of basiliximab use in liver transplantation.

DATA SOURCES

We searched the associated publications in English from July 1998 to December 2015 in the following databases: MEDLINE, PubMed, Ovid, EMBASE, Web of Science and Cochrane Library.

RESULTS

Basiliximab significantly decreased the incidence of de novo diabetes mellitus after liver transplantation (RR=0.56; 95% CI: 0.34-0.91; P=0.02). Subgroup analysis showed that basiliximab in combination with steroids-free immunosuppressant significantly decreased the incidence of biopsy-proven acute rejection (RR=0.62; 95% CI: 0.39-0.97; P=0.04) and new-onset hypertension (RR=0.62; 95% CI: 0.42-0.93; P=0.02).

CONCLUSIONS

Basiliximab may be effective in reducing de novo diabetes mellitus. What is more, basiliximab in combination with steroids-free immunosuppressant shows statistical benefit to reduce biopsy-proven acute rejection and de novo hypertension.

Selection and use of immunosuppressive therapies after liver transplantation: current German practice

In recent years, immunosuppression (IS) after liver transplantation (LT) has become increasingly diversified as the choice of agents has expanded and clinicians seek to optimize the balance of immunosuppressive potency with the risk of adverse events in individual patients. Calcineurin inhibitors (CNIs) are the primary agents used for patients undergoing liver transplantation. Other therapeutic agents like interleukin-2 receptor antagonists are not universally administered, but can be considered for the delay or reduction in CNI exposure. An early addition of mycophenolate mofetil (MMF) or the mTOR inhibitor everolimus also allows for the reduction in the CNI dose. To reduce the risk of malignancy, in particular of skin tumors, as well as to prevent the deterioration of renal function, everolimus-based therapy may be advantageous. Apart from patients with autoimmune hepatitis, steroids are withdrawn within 3-6 months after transplantation. Overall, immunosuppression can only be standardized in a limited proportion of patients due to specific clinical requirements and risk factors. Future studies should attempt to refine accurate individualization of the immunosuppressive regimen in specific difficult-to-treat patient subpopulations.

Evaluation of Posttransplantation Diabetes Mellitus After Liver Transplantation: Assessment of Insulin Administration as a Risk Factor

BACKGROUND

Impaired glucose regulation posttransplantation can affect allograft survival and may lead to the development of posttransplant diabetes mellitus (PTDM).

OBJECTIVES

The primary purpose of this study is to assess the difference in insulin burden between liver transplant patients who develop PTDM and patients who do not.

METHODS

This was a single-center, retrospective study. Adult liver transplant recipients transplanted between January 1, 2005, and August 1, 2013, were included. PTDM was defined as: (1) use of an oral antihyperglycemic agent for ≥30 consecutive days after transplant, (2) use of insulin ≥30 consecutive days after transplant, or (3) hemoglobin A1C≥6.5 any time after transplant.

RESULTS

Of the 114 patients included, 48 (42%) developed PTDM. The average 24-hour insulin requirement on the medical floors was 17.2 ± 14.5 units in the PTDM group and 11.3 ± 12.2 units in the PTDM-free group;P= 0.02. The average blood glucose level on the medical floor was 184.7 ± 31.5 mg/dL in the PTDM group and 169.3 ± 31.4 mg/dL in the PTDM-free group;P= 0.013. Multivariate analysis revealed that experiencing rejection was positively associated with the development of PTDM: adjusted odds ratio (AOR) = 3.237; 95% CI = 1.214-8.633. Basiliximab was negatively associated with the development of PTDM: AOR = 0.182; 95% CI = 0.040-0.836.

CONCLUSION

Univariate analyses suggest that insulin burden is a positive risk factor for the development of PTDM; this association is lost in multivariate analyses. Rejection was a positive predictor, and use of basiliximab was a negative predictor for the development of PTDM.

Deviation from intention to treat analysis in randomised trials and treatment effect estimates: meta-epidemiological study

OBJECTIVE

To examine whether deviation from the standard intention to treat analysis has an influence on treatment effect estimates of randomised trials.

DESIGN

Meta-epidemiological study.

DATA SOURCES

Medline, via PubMed, searched between 2006 and 2010; 43 systematic reviews of interventions and 310 randomised trials were included.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

From each year searched, random selection of 5% of intervention reviews with a meta-analysis that included at least one trial that deviated from the standard intention to treat approach. Basic characteristics of the systematic reviews and randomised trials were extracted. Information on the reporting of intention to treat analysis, outcome data, risk of bias items, post-randomisation exclusions, and funding were extracted from each trial. Trials were classified as: ITT (reporting the standard intention to treat approach), mITT (reporting a deviation from the standard approach), and no ITT (reporting no approach). Within each meta-analysis, treatment effects were compared between mITT and ITT trials, and between mITT and no ITT trials. The ratio of odds ratios was calculated (value <1 indicated larger treatment effects in mITT trials than in other trial categories).

RESULTS

50 meta-analyses and 322 comparisons of randomised trials (from 84 ITT trials, 118 mITT trials, and 108 no ITT trials; 12 trials contributed twice to the analysis) were examined. Compared with ITT trials, mITT trials showed a larger intervention effect (pooled ratio of odds ratios 0.83 (95% confidence interval 0.71 to 0.96), P=0.01; between meta-analyses variance τ(2)=0.13). Adjustments for sample size, type of centre, funding, items of risk of bias, post-randomisation exclusions, and variance of log odds ratio yielded consistent results (0.80 (0.69 to 0.94), P=0.005; τ(2)=0.08). After exclusion of five influential studies, results remained consistent (0.85 (0.75 to 0.98); τ(2)=0.08). The comparison between mITT trials and no ITT trials showed no statistical difference between the two groups (adjusted ratio of odds ratios 0.92 (0.70 to 1.23); τ(2)=0.57).

CONCLUSIONS

Trials that deviated from the intention to treat analysis showed larger intervention effects than trials that reported the standard approach. Where an intention to treat analysis is impossible to perform, authors should clearly report who is included in the analysis and attempt to perform multiple imputations.

Antibody induction versus placebo, no induction, or another type of antibody induction for liver transplant recipients

BACKGROUND

Liver transplantation is an established treatment option for end-stage liver failure. To date, no consensus has been reached on the use of immunosuppressive T-cell antibody induction for preventing rejection after liver transplantation.

OBJECTIVES

To assess the benefits and harms of immunosuppressive T-cell specific antibody induction compared with placebo, no induction, or another type of T-cell specific antibody induction for prevention of acute rejection in liver transplant recipients.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Science Citation Index Expanded, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) until September 2013.

SELECTION CRITERIA

Randomised clinical trials assessing immunosuppression with T-cell specific antibody induction compared with placebo, no induction, or another type of antibody induction in liver transplant recipients. Our inclusion criteria stated that participants within each included trial should have received the same maintenance immunosuppressive therapy. We planned to include trials with all of the different types of T-cell specific antibodies that are or have been used for induction (ie., polyclonal antibodies (rabbit of horse antithymocyte globulin (ATG), or antilymphocyte globulin (ALG)), monoclonal antibodies (muromonab-CD3, anti-CD2, or alemtuzumab), and interleukin-2 receptor antagonists (daclizumab, basiliximab, BT563, or Lo-Tact-1)).

DATA COLLECTION AND ANALYSIS

We used RevMan analysis for statistical analysis of dichotomous data with risk ratio (RR) and of continuous data with mean difference (MD), both with 95% confidence intervals (CIs). We assessed the risk of systematic errors (bias) using bias risk domains with definitions. We used trial sequential analysis to control for random errors (play of chance). We presented outcome results in a summary of findings table.

MAIN RESULTS

We included 19 randomised clinical trials with a total of 2067 liver transplant recipients. All 19 trials were with high risk of bias. Of the 19 trials, 16 trials were two-arm trials, and three trials were three-arm trials. Hence, we found 25 trial comparisons with antibody induction agents: interleukin-2 receptor antagonist (IL-2 RA) versus no induction (10 trials with 1454 participants); monoclonal antibody versus no induction (five trials with 398 participants); polyclonal antibody versus no induction (three trials with 145 participants); IL-2 RA versus monoclonal antibody (one trial with 87 participants); and IL-2 RA versus polyclonal antibody (two trials with 112 participants). Thus, we were able to compare T-cell specific antibody induction versus no induction (17 trials with a total of 1955 participants). Overall, no difference in mortality (RR 0.91; 95% CI 0.64 to 1.28; low-quality of evidence), graft loss including death (RR 0.92; 95% CI 0.71 to 1.19; low-quality of evidence), and adverse events ((RR 0.97; 95% CI 0.93 to 1.02; low-quality evidence) outcomes was observed between any kind of T-cell specific antibody induction compared with no induction when the T-cell specific antibody induction agents were analysed together or separately. Acute rejection seemed to be reduced when any kind of T-cell specific antibody induction was compared with no induction (RR 0.85, 95% CI 0.75 to 0.96; moderate-quality evidence), and when trial sequential analysis was applied, the trial sequential monitoring boundary for benefit was crossed before the required information size was obtained. Furthermore, serum creatinine was statistically significantly higher when T-cell specific antibody induction was compared with no induction (MD 3.77 μmol/L, 95% CI 0.33 to 7.21; low-quality evidence), as well as when polyclonal T-cell specific antibody induction was compared with no induction, but this small difference was not clinically significant. We found no statistically significant differences for any of the remaining predefined outcomes - infection, cytomegalovirus infection, hepatitis C recurrence, malignancy, post-transplant lymphoproliferative disease, renal failure requiring dialysis, hyperlipidaemia, diabetes mellitus, and hypertension - when the T-cell specific antibody induction agents were analysed together or separately. Limited data were available for meta-analysis on drug-specific adverse events such as haematological adverse events for antithymocyte globulin. No data were found on quality of life.When T-cell specific antibody induction agents were compared with another type of antibody induction, no statistically significant differences were found for mortality, graft loss, and acute rejection for the separate analyses. When interleukin-2 receptor antagonists were compared with polyclonal T-cell specific antibody induction, drug-related adverse events were less common among participants treated with interleukin-2 receptor antagonists (RR 0.23, 95% CI 0.09 to 0.63; low-quality evidence), but this was caused by the results from one trial, and trial sequential analysis could not exclude random errors. We found no statistically significant differences for any of the remaining predefined outcomes: infection, cytomegalovirus infection, hepatitis C recurrence, malignancy, post-transplant lymphoproliferative disease, renal failure requiring dialysis, hyperlipidaemia, diabetes mellitus, and hypertension. No data were found on quality of life.

AUTHORS' CONCLUSIONS

The effects of T-cell antibody induction remain uncertain because of the high risk of bias of the randomised clinical trials, the small number of randomised clinical trials reported, and the limited numbers of participants and outcomes in the trials. T-cell specific antibody induction seems to reduce acute rejection when compared with no induction. No other clear benefits or harms were associated with the use of any kind of T-cell specific antibody induction compared with no induction, or when compared with another type of T-cell specific antibody. Hence, more randomised clinical trials are needed to assess the benefits and harms of T-cell specific antibody induction compared with placebo, and compared with another type of antibody, for prevention of rejection in liver transplant recipients. Such trials ought to be conducted with low risks of systematic error (bias) and low risk of random error (play of chance).

Antibody induction versus corticosteroid induction for liver transplant recipients

BACKGROUND

Liver transplantation is an established treatment option for end-stage liver failure. To date, no consensus has been reached on the use of immunosuppressive T-cell specific antibody induction compared with corticosteroid induction of immunosuppression after liver transplantation.

OBJECTIVES

To assess the benefits and harms of T-cell specific antibody induction versus corticosteroid induction for prevention of acute rejection in liver transplant recipients.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Science Citation Index Expanded, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 30 September 2013 together with reference checking, citation searching, contact with trial authors and pharmaceutical companies to identify additional trials.

SELECTION CRITERIA

We included all randomised clinical trials assessing immunosuppression with T-cell specific antibody induction versus corticosteroid induction in liver transplant recipients. Our inclusion criteria stated that participants within each included trial should have received the same maintenance immunosuppressive therapy.

DATA COLLECTION AND ANALYSIS

We used RevMan for statistical analysis of dichotomous data with risk ratio (RR) and of continuous data with mean difference (MD), both with 95% confidence intervals (CIs). We assessed risk of systematic errors (bias) using bias risk domains with definitions. We used trial sequential analysis to control for random errors (play of chance).

MAIN RESULTS

We included 10 randomised trials with a total of 1589 liver transplant recipients, which studied the use of T-cell specific antibody induction versus corticosteroid induction. All trials were with high risk of bias. We compared any kind of T-cell specific antibody induction versus corticosteroid induction in 10 trials with 1589 participants, including interleukin-2 receptor antagonist induction versus corticosteroid induction in nine trials with 1470 participants, and polyclonal T-cell specific antibody induction versus corticosteroid induction in one trial with 119 participants.Our analyses showed no significant differences regarding mortality (RR 1.01, 95% CI 0.72 to 1.43), graft loss (RR 1.12, 95% CI 0.82 to 1.53) and acute rejection (RR 0.84, 95% CI 0.70 to 1.00), infection (RR 0.96, 95% CI 0.85 to 1.09), hepatitis C virus recurrence (RR 0.89, 95% CI 0.79 to 1.00), malignancy (RR 0.59, 95% CI 0.13 to 2.73), and post-transplantation lymphoproliferative disorder (RR 1.00, 95% CI 0.07 to 15.38) when any kind of T-cell specific antibody induction was compared with corticosteroid induction (all low-quality evidence). Cytomegalovirus infection was less frequent in patients receiving any kind of T-cell specific antibody induction compared with corticosteroid induction (RR 0.50, 95% CI 0.33 to 0.75; low-quality evidence). This was also observed when interleukin-2 receptor antagonist induction was compared with corticosteroid induction (RR 0.55, 95% CI 0.37 to 0.83; low-quality evidence), and when polyclonal T-cell specific antibody induction was compared with corticosteroid induction (RR 0.21, 95% CI 0.06 to 0.70; low-quality evidence). However, when trial sequential analysis regarding cytomegalovirus infection was applied, the required information size was not reached. Furthermore, diabetes mellitus occurred less frequently when T-cell specific antibody induction was compared with corticosteroid induction (RR 0.45, 95% CI 0.34 to 0.60; low-quality evidence), when interleukin-2 receptor antagonist induction was compared with corticosteroid induction (RR 0.45, 95% CI 0.35 to 0.61; low-quality evidence), and when polyclonal T-cell specific antibody induction was compared with corticosteroid induction (RR 0.12, 95% CI 0.02 to 0.95; low-quality evidence). When trial sequential analysis was applied, the trial sequential monitoring boundary for benefit was crossed. We found no subgroup differences for type of interleukin-2 receptor antagonist (basiliximab versus daclizumab). Four trials reported on adverse events. However, no differences between trial groups were noted. Limited data were available for meta-analysis on drug-specific adverse events such as haematological adverse events for antithymocyte globulin. No data were available on quality of life.

AUTHORS' CONCLUSIONS

Because of the low quality of the evidence, the effects of T-cell antibody induction remain uncertain. T-cell specific antibody induction seems to reduce diabetes mellitus and may reduce cytomegalovirus infection when compared with corticosteroid induction. No other clear benefits or harms were associated with the use of T-cell specific antibody induction compared with corticosteroid induction. For some analyses, the number of trials investigating the use of T-cell specific antibody induction after liver transplantation is small, and the numbers of participants and outcomes in these randomised trials are limited. Furthermore, the included trials are heterogeneous in nature and have applied different types of T-cell specific antibody induction therapy. All trials were at high risk of bias. Hence, additional randomised clinical trials are needed to assess the benefits and harms of T-cell specific antibody induction compared with corticosteroid induction for liver transplant recipients. Such trials ought to be conducted with low risks of systematic error and of random error.

Elevation of CD4+ differentiated memory T cells is associated with acute cellular and antibody-mediated rejection after liver transplantation

BACKGROUND

It is now well known that the outcome after allogeneic transplantation, such as incidence of acute rejections, very much depends on the individual's immune reactivity status. There is also increasing evidence that the presence of preexisting memory T cells can affect antigraft immune responses.

METHODS

In a prospective study, we monitored peripheral CD4 and CD8 central memory, effector memory, and terminal differentiated effector memory (TEMRA) T cells in 55 patients who underwent deceased liver transplantation and received conventional immunosuppressive treatment with or without basiliximab induction. The primary endpoint of the study was acute allograft rejection during a 1-year follow-up period.

RESULTS

We observed significantly increased proportions of CD4 and CD8 TEMRA cells in patients before transplantation compared with healthy controls (P=0.006 and 0.009, respectively). This characteristic was independent of the underlying disease. In patients with no signs of acute rejection, we observed an immediate reduction of CD4 TEMRA cells. In contrast, patients who experienced acute cellular rejection, and especially antibody-mediated rejection, displayed persistent elevated TEMRA cells (P=0.017 and 0.027, respectively). Basiliximab induction therapy did not influence CD4 and CD8 TEMRA numbers.

CONCLUSIONS

Conventional immunosuppressive or basiliximab treatment cannot control the persistence of TEMRA T cells, which may contribute to acute cellular rejection and antibody-mediated rejection after liver transplantation. In the future, specific targeting of TEMRA cells in selected patients may prevent the occurrence of difficult to treat steroid-resistant rejections, thereby leading to improved patient outcome.

Induction immunosuppression in liver transplantation: a review

Antibody therapy for induction is seldom used in liver transplantation in the United States, but continues to be used in approximately 10% of patients. The most commonly used antibody at the current time is basiliximab (Simulect, Novartis) and is used in adults with renal dysfunction at the time of liver transplantation with the intention of delaying introduction of calcineurin-inhibitors. In children, the same antibody is commonly used in order to reduce rates of acute rejection. Most patients, adult and pediatric, are treated with initially higher levels of tacrolimus rather than antibody induction.

Review article: use of induction therapy in liver transplantation

Induction therapy is used relatively infrequently in liver transplantation, but developments in induction regimens and strategies for their use are prompting a re-examination of its benefits. Rabbit antithymocyte globulin (rATG) induces protracted, dose-dependent lymphocytopenia with preferential reconstitution of regulatory T-lymphocytes. Non-depleting interleukin-2 receptor antagonists (IL-2RA) act selectively on activated T-lymphocytes with a shorter duration of effect. IL-2RA induction with delayed and reduced calcineurin inhibitor (CNI) exposure appears to preserve efficacy, while more aggressive CNI minimisation has been attempted successfully using rATG. Steroid-free tacrolimus monotherapy with rATG or IL-2RA induction is effective if adequate tacrolimus exposure is maintained. Early concerns that addition of induction to a conventional maintenance regimen could lead to accelerated progression of hepatitis C disease, or to an increased risk of hepatocellular cancer recurrence, now appear unfounded using modern regimens. Similarly, with routine use of systemic prophylaxis, recent prospective and retrospective data have not shown a higher rate of infections overall, or cytomegalovirus infection specifically, using rATG or IL-2RA induction. Historical evidence that lymphocyte-depleting agents increased the risk of non-Hodgkin lymphoma has not been confirmed for rATG. Wider use of induction in liver transplantation is now merited, using individualized strategies to support reduced CNI exposure or steroid-free immunosuppression.

Innate and adaptive immune responses in asthma

The recognition that asthma is primarily an inflammatory disorder of the airways associated with T helper type 2 (T(H)2) cell-dependent promotion of IgE production and recruitment of mast cells and eosinophils has provided the rationale for disease control using inhaled corticosteroids and other anti-inflammatory drugs. As more has been discovered about the cytokine, chemokine and inflammatory pathways that are associated with T(H)2-driven adaptive immunity, attempts have been made to selectively inhibit these in the hope of discovering new therapeutics as predicted from animal models of allergic inflammation. The limited success of this approach, together with the recognition that asthma is more than allergic inflammation, has drawn attention to the innate immune response in this disease. Recent advances in our understanding of the sentinel role played by innate immunity provides new targets for disease prevention and treatment. These include pathways of innate stimulation by environmental or endogenous pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) to influence the activation and trafficking of DCs, innate sources of cytokines, and the identification of new T cell subsets and lymphoid cells.

Opposing functions of IL-2 and IL-7 in the regulation of immune responses

Regulation of the magnitude and quality of immune responses is dependent on the integration of multiple signals which typically operate through positive and negative feedback loops. Cytokines that promote or limit T cell expansion and differentiation are often both present in the complex lymphoid environment where antigen-initiated T cell responses take place. The nature and strength of the cytokine signal received by the responding cell, as well as by surrounding regulatory cells, will determine the extent of clonal expansion and the progression towards effector and memory cell differentiation. The mechanisms that determine how much cytokine is produced and how cytokine activities are controlled by receptor expression and intracellular regulators of signaling are not fully understood. Here we discuss the opposing functions of two members of the common receptor gamma chain (γc) cytokines, IL-2 and IL-7 in the generation and regulation of immune responses in vivo.