A randomized and prospective study comparing treatment with high-dose intravenous immunoglobulin with monoclonal antibodies for rescue of kidney grafts with steroid-resistant rejection

Anti-thymocyte globulin for treatment of T-cell-mediated allograft rejection

Anti-thymocyte globulin (ATG) is a pivotal immunosuppressive therapy utilized in the management of T-cell-mediated rejection and steroid-resistant rejection among renal transplant recipients. Commercially available as Thymoglobulin (rabbit-derived, Sanofi, United States), ATG-Fresenius S (rabbit-derived), and ATGAM (equine-derived, Pfizer, United States), these formulations share a common mechanism of action centered on their interaction with cell surface markers of immune cells, imparting immunosuppressive effects. Although the prevailing mechanism predominantly involves T-cell depletion via the com plement-mediated pathway, alternate mechanisms have been elucidated. Optimal dosing and treatment duration of ATG have exhibited variance across ran domised trials and clinical reports, rendering the establishment of standardized guidelines a challenge. The spectrum of risks associated with ATG administration spans from transient adverse effects such as fever, chills, and skin rash in the acute phase to long-term concerns related to immunosuppression, including susceptibility to infections and malignancies. This comprehensive review aims to provide a thorough exploration of the current understanding of ATG, encom passing its mechanism of action, clinical utility in the treatment of acute renal graft rejections, specifically steroid-resistant cases, efficacy in rejection episode reversal, and a synthesis of findings from different eras of maintenance immunosuppression. Additionally, it delves into the adverse effects associated with ATG therapy and its impact on long-term graft function. Furthermore, the review underscores the existing gaps in evidence, particularly in the context of the Banff classification of rejections, and highlights the challenges faced by clinicians when navigating the available literature to strike the optimal balance between the risks and benefits of ATG utilization in renal transplantation.

Immune Checkpoint Inhibitors in Solid Organ Transplant Recipients With Advanced Skin Cancers-Emerging Strategies for Clinical Management

Use of immune checkpoint inhibitors (ICIs) in solid organ transplant recipients (SOTRs) with advanced skin cancers presents a significant clinical management dilemma. SOTRs and other immunosuppressed patients have been routinely excluded from ICI clinical trials with good reason: immune checkpoints play an important role in self- and allograft-tolerance and risk of acute allograft rejection reported in retrospective studies affects 10% to 65% of cases. These reports also confirm that cutaneous squamous cell carcinoma and melanoma respond to ICI therapy, although response rates are generally lower than those observed in immunocompetent populations. Prospective trials are now of critical importance in further establishing ICI efficacy and safety. However, based on current knowledge, we recommend that ICIs should be offered to kidney transplant recipients with advanced cutaneous squamous cell carcinoma, melanoma, or Merkel cell carcinoma if surgery and/or radiotherapy have failed. For kidney transplant recipients, this should be first line ahead of chemotherapy and targeted therapies. In SOTRs, the use of ICIs should be carefully considered with the benefits of ICIs versus risks of allograft rejection weighed up on a case-by-case basis as part of shared decision-making with patients. In all cases, parallel management of immunosuppression may be key to ICI responsiveness. We recommend maintaining immunosuppression before ICI initiation with a dual immunosuppressive regimen combining mammalian target of rapamycin inhibitors and either corticosteroids or calcineurin inhibitors. Such modification of immunosuppression must be considered in the context of allograft risk (both rejection and also its subsequent treatment) and risk of tumor progression. Ultimately, a multidisciplinary approach should underpin all clinical decision-making in this challenging scenario.

Histologic and Molecular Patterns in Responders and Non-responders With Chronic-Active Antibody-Mediated Rejection in Kidney Transplants

Introduction

There is no proven therapy for chronic-active antibody-mediated rejection (caABMR), the major cause of late kidney allograft failure. Histological and molecular patterns associated with possible therapy responsiveness are not known.

Methods

Based on rigorous selection criteria this single center, retrospective study identified 16 out of 1027 consecutive kidney transplant biopsies taken between 2008 and 2016 with pure, unquestionable caABMR, without other pathologic features. The change in estimated GFR pre- and post-biopsy/treatment were utilized to differentiate subjects into responders and non-responders. Gene sets reflecting active immune processes of caABMR were defined a priori, including endothelial, inflammatory, cellular, interferon gamma (IFNg) and calcineurin inhibitor (CNI) related-genes based on the literature. Transcript measurements were performed in RNA extracted from stored, formalin-fixed, paraffin-embedded (FFPE) samples using NanoString™ technology. Histology and gene expression patterns of responders and non-responders were compared.

Results

A reductionist approach applying very tight criteria to identify caABMR and treatment response excluded the vast majority of clinical ABMR cases. Only 16 out of 139 cases with a written diagnosis of chronic rejection fulfilled the caABMR criteria. Histological associations with therapy response included a lower peritubular capillaritis score (p = 0.028) along with less glomerulitis. In contrast, no single gene discriminated responders from non-responders. Activated genes associated with NK cells and endothelial cells suggested lack of treatment response.

Conclusion

In caABMR active microvascular injury, in particular peritubular capillaritis, differentiates treatment responders from non-responders. Transcriptome changes in NK cell and endothelial cell associated genes may further help to identify treatment response. Future prospective studies will be needed which include more subjects, who receive standardized treatment protocols to identify biomarkers for treatment response.

Clinical Trial Registration

[ClinicalTrials.gov], identifier [NCT03430414].

Intravenous Immunoglobulin Administration Significantly Increases BKPyV Genotype-Specific Neutralizing Antibody Titers in Kidney Transplant Recipients

BK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN) is one of the major causes of kidney graft dysfunction, and there are no BKPyV-specific antiviral therapies available. BKPyV neutralizing antibodies (NAbs) play key roles in protecting against BKPyV replication and represent a potential therapeutic or preventive strategy. In this study, we evaluated NAb titers in intravenous immunoglobulin (i.v. Ig) preparations and in kidney transplant recipients (KTR) before and after i.v. Ig administration. NAb titers directed against major BKPyV genotypes were measured using a BKPyV pseudovirion system. Thirty-three KTR receiving high (1 g/kg of body weight/day; n = 17) or low (0.4 g/kg/day; n = 16) i.v. Ig doses were included. Median NAb titers in i.v. Ig preparations ranged from 5.9 log₁₀ 50% inhibitory concentration (IC₅₀) for genotype I to 4.1 log₁₀ IC₅₀ for genotype IV. A mean of 90% of patients (range, 88% to 100%) displaying low or negative BKPyV NAb titers against genotype I reached 4 log₁₀ IC₅₀ after the first i.v. Ig administration. This value was reached by a mean of 44% (range, 13% to 83%) and 19% (range, 0% to 38%) of patients against genotype II and genotype IV, respectively. The benefit of i.v. Ig administration persisted until the following course of treatment (day 22 ± 7 days) for genotypes I and II, and no cumulative effect was observed through the three doses. Our findings demonstrate that i.v. Ig administration results in a significant increase in BKPyV NAb titers in KTR. These in vitro and in vivo pharmacokinetic data provide the rationale for a proof-of-concept study investigating the efficacy of i.v. Ig for the prevention of BKPyV infection in KTR.

Role of Immunoglobulin Therapy to Prevent and Treat Infections

Immunoglobulins have been used widely in medicine for a variety of diseases including infectious diseases. While the main clinical applications of immunoglobulin therapy concern their use as replacement for patients with primary immunodeficiencies, or as treatment for autoimmune and inflammatory disorders, their role in infectious disease is limited largely to viral and toxin neutralization and replacement therapy in patients with immunoglobulin deficiencies. Many aspects of the therapeutic regimen of immunoglobulins even in the established indications remain open. Recently, due to the worldwide surge of immunosuppression caused by AIDS, organ transplantation, cancer, and autoimmune therapies, as well as the emergence of multidrug-resistant bacteria, there has been renewed interest in the use of antibody preparation to prevent infections in high-risk groups.

Knowing the limitations of the current anti-infective armamentarium, approaches that target the host through manipulations to augment the host immune response provide a helpful aid to conventional treatment options. A substantial body of evidence has demonstrated that strategies aiming to support or stimulate immune response could be feasible approaches that would benefit immunocompromised patients. In the present chapter, we present contemporary indications of immunoglobulin administration for therapy and prophylaxis of infections in the immunocompromised population.

Polyclonal and monoclonal antibodies for treating acute rejection episodes in kidney transplant recipients

BACKGROUND

Registry data shows that the incidence of acute rejection has been steadily falling. Approximately 10% to 35% of kidney recipients will undergo treatment for at least one episode of acute rejection within the first post-transplant year. Treatment options include pulsed steroid therapy, the use of an antibody preparation, the alteration of background immunosuppression, or combinations of these options. Over recent years, new treatment strategies have evolved, and in many parts of the world there has been an increase in use of tacrolimus and mycophenolate and a reduction in the use of cyclosporin and azathioprine use as baseline immunosuppression to prevent acute rejection. There are also global variations in use of polyclonal and monoclonal antibodies to treat acute rejection. This is an update of a review published in 2006.

OBJECTIVES

The aim of this systematic review was to: (1) to evaluate the relative and absolute effects of different classes of antibody preparation in preventing graft loss and resolving cellular or humoral rejection episodes when used as a treatment for first episode of rejection in kidney transplant recipients; (2) evaluate the relative and absolute effects of different classes of antibody preparation in preventing graft loss and resolving cellular or humoral rejection episodes when used as a treatment for steroid-resistant rejection in kidney transplant recipients; (3) determine how the benefits and adverse events vary for each type of antibody preparation; and (4) determine how the benefits and harms vary for different formulations of antibody within each type.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 18 April 2017 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in all languages comparing all mono- and polyclonal antibody preparations, given in combination with any other immunosuppressive agents, for the treatment of cellular or humoral graft rejection, when compared to any other treatment for acute rejection were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias of the included studies and extracted data. Statistical analyses were performed using a random-effects model and results expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 11 new studies (18 reports, 346 participants) in this update, bring the total number of included studies to 31 (76 reports, 1680 participants). Studies were generally small, incompletely reported, especially for potential harms, and did not define outcome measures adequately. The risk of bias was inadequate or unclear risk for random sequence generation (81%), allocation concealment (87%) and other bias (87%). There were, however, a predominance of low risk of bias for blinding (75%) and incomplete outcome data (80%) across all the studies. Selective reporting had a mixture of low (58%), high (29%), and unclear (13%) risk of bias.Seventeen studies (1005 participants) compared therapies for first acute cellular rejection episodes. Antibody therapy was probably better than steroid in reversing acute cellular rejection (RR 0.50, 95% CI 0.30 to 0.82; moderate certainty) and preventing subsequent rejection (RR 0.70, 95% CI 0.50 to 0.99; moderate certainty), may be better for preventing graft loss (death censored: (RR 0.80, 95% CI 0.57 to 1.12; low certainty) but there was little or no difference in death at one year. Adverse effects of treatment (including fever, chills and malaise following drug administration) were probably reduced with steroid therapy (RR 23.88, 95% CI 5.10 to 111.86; I2 = 16%; moderate certainty).Twelve studies (576 patients) investigated antibody treatment for steroid-resistant rejection. There was little or no benefit of muromonab-CD3 over ATG or ALG in reversing rejection, preventing subsequent rejection, or preventing graft loss or death. Two studies compared the use of rituximab for treatment of acute humoral rejection (58 patients). Muromonab-CD3 treated patients suffered three times more than those receiving either ATG or T10B9, from a syndrome of fever, chills and malaise following drug administration (RR 3.12, 95% CI 1.87 to 5.21; I2 = 31%), and experienced more neurological side effects (RR 13.10 95% CI 1.43 to 120.05; I2 = 36%) (low certainty evidence).There was no evidence of additional benefit from rituximab in terms of either reversal of rejection (RR 0.94, 95% CI 0.54 to 1.64), or graft loss or death 12 months (RR 1.0, 95% CI 0.23 to 4.35). Rituximab plus steroids probably increases the risk of urinary tract infection/pyelonephritis (RR 5.73, 95% CI 1.80 to 18.21).

AUTHORS' CONCLUSIONS

In reversing first acute cellular rejection and preventing graft loss, any antibody is probably better than steroid, but there is little or no difference in subsequent rejection and patient survival. In reversing steroid-resistant rejection there was little or no difference between different antibodies over a period of 12 months, with limited data beyond that time frame. In treating acute humoral rejection, there was no evidence that the use of antibody therapy conferred additional benefit in terms of reversal of rejection, or death or graft loss.Although this is an updated review, the majority of newer included studies provide additional evidence from the cyclosporin/azathioprine era of kidney transplantation and therefore conclusions cannot necessarily be extrapolated to patients treated with more contemporary immunosuppressive regimens which include tacrolimus/mycophenolate or sirolimus. However, many kidney transplant centres around the world continue to use older immunosuppressive regimes and the findings of this review remain strongly relevant to their clinical practice.Larger studies with standardised reproducible outcome criteria are needed to investigate the outcomes and risks of antibody treatments for acute rejection in kidney transplant recipients receiving contemporary immunosuppressive regimes.

Treatment of Antibody-Mediated Renal Allograft Rejection: Improving Step by Step

Throughout the past years we stepwise modified our immunosuppressive treatment regimen for patients with antibody-mediated rejection (ABMR). Here, we describe three consecutive groups treated with different regimens. From 2005 until 2008, we treated all patients with biopsy-proven ABMR with rituximab (500 mg), low-dose (30 g) intravenous immunoglobulins (IVIG), and plasmapheresis (PPH, 6x) (group RLP, n = 12). Between 2009 and June 2010, patients received bortezomib (1.3 mg/m², 4x) together with low-dose IVIG and PPH (group BLP, n = 11). In July 2010, we increased the IVIG dose and treated all subsequent patients with bortezomib, high-dose IVIG (1.5 g/kg), and PPH (group BHP, n = 11). Graft survival at three years after treatment was 73% in group BHP as compared to 45% in group BLP and 25% in group RLP. At six months after treatment median serum creatinine was 2.1 mg/dL, 2.9 mg/dL, and 4.2 mg/dL in groups BHP, BLP, and RLP, respectively (p = 0.02). Following treatment, a significant decrease of donor-specific HLA antibody (DSA) mean fluorescence intensity from 8467 ± 6876 to 5221 ± 4711 (p = 0.01) was observed in group BHP, but not in the other groups. Our results indicate that graft survival, graft function, and DSA levels could be improved along with stepwise modifications to our treatment regimen, that is, the introduction of bortezomib and high-dose IVIG treatment.

Immunomodulation by hyperimmunoglobulins after solid organ transplantation: Beyond prevention of viral infection

Hyperimmunoglobulins are pharmaceutical formulations of human IgG which contain high titers of antibodies against specific viruses. They have been successfully used in solid organ transplantation (SOT) to prevent Cytomegalovirus (CMV) and Hepatitis B Virus (HBV) infection. The introduction of effective and cheaper antiviral drugs has resulted in decreasing usage of hyperimmunoglobulins in SOT. However, it may still be attractive to combine antiviral drug therapy with hyperimmunoglobulins after SOT, as there is some evidence that hyperimmunoglobulins, similar to high doses of intravenous immunoglobulins (IVIgs), might exert anti-inflammatory activity and thereby prevent immunological graft damage and improve graft and patient survival. In this review we discuss the existing clinical evidence for beneficial anti-inflammatory effects of hyperimmunoglobulins after cardiac, lung, kidney, and liver transplantation. Only a limited number of studies have addressed this issue, and these studies often included small patient cohorts and showed considerable variations in the type, intensity and duration of treatment regimens. Due to these limitations, it is difficult to draw firm conclusions. Retrospective studies consistently demonstrated that addition of CMV hyperimmunoglobulin (CMV-Ig) to antiviral drug prophylaxis after lung transplantation is associated with reduced rates of CMV disease and bronchiolitis obliterans syndrome (BOS), and improved patient survival. The doses of CMV-Ig administered after SOT are much lower than the minimal effective dose of IVIg used for anti-inflammatory therapy in auto-immune diseases. Therefore, it is questionable whether the reduced incidence of BOS is the result of 'direct' anti-inflammatory effects of CMV-Ig or is caused by a reduction of CMV infection, which is a risk factor for BOS. No or very limited evidence for better prevention of immunological graft damage by anti-CMV combination therapy is available for heart, kidney and liver transplant patients. In liver transplantation published evidence suggests that the high-doses of Hepatitis B virus hyperimmunoglobulin (HBIg) administered to prevent HBV-infection may reduce the risk of acute rejection, while combination therapy of HBIg and antiviral drugs in HBV-infected patients is consistently associated with better graft and patient survival compared to antiviral monotherapy. Well-designed prospective randomized studies with larger patient cohorts are needed to substantiate the current limited evidence for anti-inflammatory benefits of hyperimmunoglobulins besides prevention of CMV and HBV infection after SOT.

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

Immunoglobulin G promotes skin graft acceptance in an immunologically potent rat model

Immunoglobulin G (IgG) has been shown to protect graft rejection after transplantation, whereas the molecular mechanism of IgG in promoting graft acceptance has not been well established. In this study, we tested the effectiveness of IgG in preventing rejection of transplanted skin graft in an immunologically potent rat model, and studied the mechanism of this protection. We found that systemic or local administration of IgG significantly prolonged the survival of skin grafts with the immune tolerance induced by IgG and subcutaneous local injection of 1mg IgG to adult SD rat yielded the longest survival of skin grafts from 5.8 to 17.3 days. We also found that IgG reduced the number of pro-inflammatory cells especially lymphocytes, neutrophils and basophils, increased the seral levels of anti-inflammatory factors including IL-10 and IL-4, and activated CD4+CD25+Foxp3+ regulatory T cells, unveiling the mechanisms of this protective effect. These findings provide new insight to support clinical application of IgG in treating transplantation.

Efficacy of rabbit anti-thymocyte globulin for steroid-resistant acute rejection after liver transplantation

Acute cellular rejection after liver transplantation (LT) can be treated with steroid pulse therapy, but there is no ideal treatment for steroid-resistant acute rejection (SRAR). We aimed to determine the feasibility and potential complications of rabbit anti-thymocyte globulin (rATG) application to treat SRAR in liver transplant recipients. We retrospectively reviewed medical records of 429 recipients who underwent LT at Severance Hospital between January 2010 and March 2015. We compared clinical features and graft survival between patients with steroid-sensitive acute rejection (SSAR; n = 23) and SRAR (n = 11). We also analyzed complications and changes in laboratory findings after 2.5 mg/kg rATG treatment in patients with SRAR for 6 to 10 days. There were no significant differences in gender, age, model for end-stage liver disease score, Child-Turcotte-Pugh score, or original liver diseases between patients with SSAR and SRAR, although deceased donors were more frequently associated with the SRAR group (P = 0.004). All SRAR patients responded positively to rATG treatment; after treatment, the patients' median AST levels decreased from 138 to 63 IU/L, and their median ALT levels dropped from 327 to 70 IU/L 1 day after rATG treatment (P = 0.022 and 0.017, respectively). Median aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin levels significantly decreased 1 month post-treatment (P = 0.038, 0.004, and 0.041, respectively). Median survival after LT was 23 months, and median survival after rATG was 22 months in patients with SRAR. Adverse effects included hepatitis C virus (HCV) reactivation, fungemia, and cytomegalovirus (CMV) infection. Nine SRAR patients survived with healthy liver function, 1 died from a traffic accident during follow-up, and 1 died from graft-versus-host disease and fungemia. Administration of rATG is an effective therapeutic option for SRAR with acceptable complications in liver transplant recipients. However, the occurrence of HCV reactivation and CMV infection in LT patients should be monitored after rATG treatment in these patients.

Advances in pharmacotherapy to treat kidney transplant rejection

INTRODUCTION

Current immunosuppressive combination therapy provides excellent prevention of T-cell-mediated rejection following renal transplantation; however, antibody-mediated rejection remains of high concern and accounts for a large number of long-term allograft losses. The recent development of protocol biopsies resulted in the definition of subclinical rejection (SCR), showing histologic evidence for rejection but unremarkable clinical course.

AREAS COVERED

This review describes the current knowledge and evidence of pharmacotherapy to treat kidney allograft rejections and covers SCR treatment options. Each substance is analyzed with regard to its classical indication and further discussed for the treatment of other forms of rejection.

EXPERT OPINION

Despite a lack of randomized trials, early acute T-cell-mediated rejection can be treated effectively in most cases without graft loss. The necessity to treat SCR is currently unclear. Due to a lack of effective therapies, new treatment approaches for antibody-mediated rejection are an urgent medical need to improve long-term outcomes. Future research should aim to better define pathophysiology and histology, stratify risk, and develop rational treatment strategies from randomized controlled trials, in order to establish the value of novel therapies in the arsenal of rejection pharmacotherapy. However, the effective prevention of rejection with minimal side effects still remains the goal in immunosuppression.

Intravenous immunoglobulin for antibody-mediated keratolimbal allograft rejection

A 33-year-old woman with congenital aniridia presented with decreased vision in her right eye. Slit lamp examination revealed diffuse conjunctivalisation of the ocular surface with mild subepithelial fibrosis consistent with aniridic keratopathy secondary to limbal stem cell deficiency. She underwent limbal stem cell transplantation with cadaver donor tissue (keratolimbal allograft (KLAL) surgery) and received systemic immunosuppression. Despite optimal combination immunosuppressive therapy managed by a renal transplant specialist, 2 weeks after the KLAL, the patient developed intractable eye pain, conjunctival injection, dilation of the KLAL graft blood vessels and limbal haemorrhages. There were no epithelial defects noted. Donor-specific antibody testing was positive, and intravenous immunoglobulin therapy was initiated. There was immediate symptomatic and objective improvement. Fifteen months postoperatively, the patient's vision was 20/400 with a stable corneal epithelium and no evidence of inflammation.

Intravenous immunoglobulin in critically ill adults: When and what is the evidence?

Intravenous immunoglobulin (IVIg) use is growing dramatically internationally due to the increasing numbers of acute and chronic conditions that may benefit from IVIg. Patients with conditions that may benefit from IVIg might require intensive care unit (ICU) admission, supporting the need to review IVIg use in the critical care setting. The most common clinical indications for IVIg in adults that may require ICU admission and are commonly supported under clinical practice guidelines are Guillain-Barré syndrome, myasthenia gravis and Lambert-Eaton myasthenic syndrome, inflammatory myopathies, and primary or secondary immunodeficiency diseases complicated by severe bacterial sepsis. Other emerging indications include necrotizing fasciitis, toxic epidermal necrolysis/Stevens-Johnson syndrome, and toxic shock syndrome. The evidence for IVIg use in sepsis and septic shock remains controversial and insufficient to recommend its routine use. Intravenous immunoglobulin is expensive and also carries risks of adverse effects, including common and benign infusion-related reactions, as well as relatively rare and more serious problems, such as thromboembolic events, renal failure, and aseptic meningitis. In this article, we review the literature on conditions requiring ICU admission and IVIg, and we classify them as supported, emerging, or unsupported indications based on the available evidence and guidelines for clinical use of IVIg.

Intravenous immunoglobulin attenuates experimental autoimmune arthritis by inducing reciprocal regulation of Th17 and Treg cells in an interleukin-10-dependent manner

OBJECTIVE

Intravenous immunoglobulin (IVIG) is used as a therapeutic agent in various autoimmune diseases. The aims of this study were to investigate the therapeutic effects of IVIG on collagen-induced arthritis (CIA) and identify the mechanism responsible for any therapeutic effects.

METHODS

IVIG was administered to mice with CIA, and the in vivo effects were determined. Th17 and Treg cell frequencies were analyzed by flow cytometry, and cytokine levels in the supernatant were measured by enzyme-linked immunosorbent assay. Subpopulations of T cells and B cells in the spleen were assessed by confocal microscopy.

RESULTS

The arthritis severity score and incidence of arthritis were lower in mice treated with IVIG compared with untreated mice. Histopathologic analysis showed less joint damage in mice treated with IVIG. The expression of proinflammatory cytokines, specific type II collagen antibodies, and osteoclast markers was significantly reduced in mice treated with IVIG. Administration of IVIG induced increased FoxP3 expression and inhibited Th17 cell development. The number of FoxP3+ Treg cells was increased, and the number of Th17 cells was decreased in the spleens of mice treated with IVIG. The number of FoxP3+ follicular helper T cells was increased, and subsequent maturation of germinal center B cells was inhibited by IVIG. In addition, IVIG up-regulated interleukin-10 (IL-10) and Fcγ receptor IIB expression. The treatment effects of IVIG on arthritis were lost in IL-10-knockout mice.

CONCLUSION

These results showed that IVIG has therapeutic effects by modulating CD4+ T cell differentiation. The therapeutic effects of IVIG are dependent on IL-10.

Induction of PD-L1 on monocytes: a new mechanism by which IVIg inhibits mixed lymphocyte reactions

Allograft rejection and graft-versus-host disease (GvHD) are frequent complications following solid organ or stem cell transplantation in which T cell activation plays a central role. Despite the development of new immunosuppressive drugs that improve the success rate of transplantation, allograft survival continues to be a challenge. Recently, intravenous immunoglobulin (IVIg) has been proposed as prophylaxis and post-transplant treatment to reduce acute rejection episodes. IVIg is a therapeutic agent that is known to down-modulate T cell functions in patients with autoimmune disorders. To test the hypothesis that this immunomodulatory effect could be beneficial in the context of transplantation, we used mixed lymphocyte reactions (MLR) as an in vitro model of allograft rejection and GvHD. Our results show that IVIg strongly inhibits the MLR as evaluated by IL-2 secretion, a well-known marker of T cell activation. IVIg also modulates the secretion of other pro-(IL-6, IFN-γ) and anti-inflammatory (IL-1RA) cytokines. More importantly, we show that IVIg induces monocytes with a CD80(low) PD-L1(high) phenotype and that blockade of PD-L1 partially abrogates the inhibitory effect of IVIg. We have thus identified a new mechanism by which IVIg inhibits T cell functions in the context of transplantation, supporting the potential usefulness of IVIg in the prevention or treatment of graft rejection and GvHD.

Acute Antibody-Mediated Rejection in Renal Transplantation: Current Clinical Management

Acute antibody mediated rejection (AMR) is recognized as a major cause of graft loss in renal transplant recipients. Early acute AMR in the first few days after transplantation occurs primarily in sensitized renal transplant recipients with donor-specific alloantibody at the time of transplant and is a relatively "pure" form of acute AMR. Late acute AMR occurs months to years after transplantation and is commonly a mixed cellular and humoral rejection. While there is no consensus regarding optimum treatment, we contend that rational therapeutic approaches are emerging and the acute episode can be managed in most instances. However, new therapies are needed to prevent ongoing chronic injury in these patients.

T-cell inhibitory capacity of hyperimmunoglobulins is influenced by the production process

Intravenous immunoglobulin (IVIg) preparations are widely used for anti-inflammatory therapy of autoimmune and systemic inflammatory diseases. Hyperimmunoglobulins enriched in neutralizing antibodies against viruses can, in addition to their virus-neutralizing activity, also exert immunomodulatory activity. Previously, we observed that Cytotect®, an anti-CMV hyperimmunoglobulin, was less effective in suppressing human T-cell responses in vitro compared to Hepatect® CP, an anti-HBV hyperimmunoglobulin. We hypothesized that the poor immunomodulatory activity of Cytotect® results from treatment with β-propiolactone during the manufacturing process. The manufacturer of these hyperimmunoglobulins has now introduced a new anti-CMV hyperimmunoglobulin, called Cytotect® CP, in which β-propiolactone treatment is omitted. Here we show that Cytotect® CP inhibits PHA-driven T-cell proliferation and cytokine production with similar efficacy as Hepatect® CP, whereas the former Cytotect® does not. In addition, Cytotect® CP inhibits allogeneic T-cell responses better than Cytotect®. Our results advocate the use of hyperimmunoglobulins that have not been exposed to β-propiolactone in order to benefit from their immunomodulatory properties.

Polyclonal and monoclonal antibodies in clinic

Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

Late and chronic antibody-mediated rejection: main barrier to long term graft survival

Antibody-mediated rejection (AMR) is an important cause of graft loss after organ transplantation. It is caused by anti-donor-specific antibodies especially anti-HLA antibodies. C4d had been regarded as a diagnosis marker for AMR. Although most early AMR episodes can be successfully controlled or reversed, late and chronic AMR remains the leading cause of late graft loss. The strategies which work in early AMR have limited effect on late/chronic episodes. Here, we reviewed the lines of evidence that late/chronic AMR is the leading cause of late graft loss, characteristics of late AMR, and current strategies in managing late/chronic AMR. More effort should be put on the management of late/chronic AMR to make a better long term graft survival.

Patients treated with high-dose intravenous immunoglobulin show selective activation of regulatory T cells

Intravenous immunoglobulin (IVIg) is used to treat autoimmune and systemic inflammatory diseases caused by derailment of humoral and cellular immunity. In this study we investigated whether IVIg treatment can modulate regulatory T cells (Tregs ) in humans in vivo. Blood was collected from IVIg-treated patients with immunodeficiency or autoimmune disease who were treated with low-dose (n = 12) or high-dose (n = 15) IVIg before, immediately after and at 7 days after treatment. Percentages and activation status of circulating CD4(+) CD25(+) forkhead box protein 3 (FoxP3(+)) Tregs and of conventional CD4(+) FoxP3(-) T-helper cells (Tconv) were measured. The suppressive capacity of Tregs purified from blood collected at the time-points indicated was determined in an ex-vivo assay. High-dose, but not low-dose, IVIg treatment enhanced the activation status of circulating Tregs , as shown by increased FoxP3 and human leucocyte antigen D-related (HLA-DR) expression, while numbers of circulating Tregs remained unchanged. The enhanced activation was sustained for at least 7 days after infusion, and the suppressive capacity of purified Tregs was increased from 41 to 70% at day 7 after IVIg treatment. The activation status of Tconv was not affected by IVIg. We conclude that high-dose IVIg treatment activates Tregs selectively and enhances their suppressive function in humans in vivo. This effect may be one of the mechanisms by which IVIg restores imbalanced immune homeostasis in patients with autoimmune and systemic inflammatory disorders.

Clinical experience with thymoglobulin and antithymocyte globulin-Fresenius as induction therapy in renal transplant patients: a retrospective study

OBJECTIVES

We describe our experiences with, and compare the outcomes of, 2 groups of renal transplant patients treated with thymoglobulin or antithymocyte globulin-Fresenius as induction therapy at transplant to reduce the incidence of acute rejection and prevent delayed allograft function.

MATERIALS AND METHODS

Twenty-four recipients of deceased-donor or living-donor kidney transplants received thymoglobulin, and 23 patients received antithymocyte globulin-Fresenius. Patient and graft survival and efficacy and safety were assessed at 3 months.

RESULTS

The demographic characteristics of both groups were comparable, but the predominant donor type was significantly different. Incidence of complications, delayed graft function, and creatinine concentrations were comparable in both groups. At 3 months after the transplant, patient survival rate was 92% in the thymoglobulin group and 96% in the antithymocyte globulin-Fresenius group (P > .05), and death-censored graft survival rate for both groups was not significantly different. Average hematocrit and lymphocyte, neutrophil, and platelet counts were comparable in both groups at 3 months' follow-up. Average white blood count at 1 month was significantly different between the groups: at 5.62 ± 2.45 × 103 cells/mm³ in the thymoglobulin group and 7.85 ± 4.10 × 103 cells/mm³ in the ATG-F group (P < .05).

CONCLUSIONS

Considering the study design limitations, we observed that our group of treated patients, safety, and efficacy of thymoglobulin and antithymocyte globulin-Fresenius were generally comparable.

Bilateral transfemoral lower extremity transplantation: result at 1 year

Upper limb transplantation has become a treatment option for upper limb amputees with good midterm results. Lower extremity transplantation has never been considered for fear of poor results. The authors present a bilateral transfemoral transplantation of lower extremities performed to a 22-year patient at 12 months of follow-up. The donor was a full HLA-mismatched female multiorgan donor. CMV status was D-/R-. A primary CMV infection coincident with an acute rejection occurred at 3 months and responded to treatment. At 1 year, the Tinel's sign is at malleolar level, there is active knee extension and active plantar flexion of the foot. The patient is walking between parallel bars. Further substantial improvements are expected with longer rehabilitation and follow-up.

Clinical applications of immunoglobulin: update

Human immunoglobulin is the most used blood product in the clinical practice. Immunoglobulin applications have increased quickly since the elucidation of its immunomodulatory and antiinflammatory properties which turned this blood product into a precious tool in the treatment of numerous diseases that present with humoral immune deficiency or that cause immune system dysfunction. Currently, the approved indications for Ig are: primary immunodeficiencies, secondary immunodeficiencies (multiple myeloma or chronic lymphoid leukemia), Kawasaki syndrome, immune thrombocytopenic purpura, Guillain Barré syndrome, graft-versus-host disease following bone marrow transplantation and repeat infections in HIV children. On the other hand, there are numerous "off-label" indications of immunoglobulin, which represent 20-60% of all clinical applications of this drug. It is important to study all these indications and, above all, the scientific evidence for its use, in order to provide patients with a new therapeutic option without burdening the health system. This review results from a wide selection of papers identified in the Pubmed and Lilacs scientific electronic databases. A group of descriptors were used from human immunoglobulin to the names of each disease that immunoglobulin is clinically applied. Our main objective is to list the numerous indications of immunoglobulin, both authorized and "off-label" and to analyze these indications in the light of the most recent scientific evidence.

Antibody-mediated kidney allograft rejection: therapeutic options and their experimental rationale

With the advent of novel therapies to directly intervene with B cell immunity and complement activation, antibody-mediated kidney allograft rejection (AMR) has come into the focus of transplant immunologists. Intravenous immunoglobulin, rituximab, bortezomib, and eculizumab have been used to treat patients with acute AMR, apart from the standard treatment of antibody removal with plasma exchange or immunoadsorption and steroid pulses. This article describes the experimental rationale and summarizes the still limited clinical experience with these novel therapies in the transplant setting. Results with the standard treatment for acute AMR, including intense plasmapheresis, intravenous immunoglobulins, and steroids are good with a graft survival of 80% at 18 months. In contrast, patients suffering from chronic AMR have significant irreversible damage in their grafts with substantially impaired graft survival. Thus, the authors propose a step-wise escalation of therapy in refractory cases of acute AMR and advocate an urgent need for controlled therapeutic trials for acute and chronic AMR not to inflict unnecessary harm on our patients by uncontrolled polypragmasy.

Intravenous immunoglobulin therapy in the treatment of BK viremia and nephropathy in pediatric renal transplant recipients

Polyoma BKVN is a significant cause of allograft dysfunction and loss in renal transplant recipients. Reduction in immunosuppression is accepted as first-line therapy to decrease viral load and prevent allograft injury and dysfunction. We report our experience with persistent BKV after reduction in immunosuppression followed by successful clearance of BKV in three pediatric renal transplant recipients and histological resolution of BKVN in a fourth patient following therapy with IVIG. Once BKV was detected, immunosuppression was reduced and BKV was monitored until clearance was achieved. All four patients were given IVIG in a dose of 2 g/kg. Allograft function remained stable in all patients. Early routine screening for BKV allows early intervention to prevent the development of BKVN and permanent allograft damage. While immunosuppression reduction is a logical first-line therapy, second-line therapy is not well established. IVIG seems to be an effective treatment for persistent BKV after reduction in immunosuppression and for BKVN and can therefore be considered as a therapeutic option in these patients.

Modulation of dendritic cells and regulatory T cells by naturally occurring antibodies

Most studies on the effects of naturally occurring autoantibodies (NAbs) on immune cells have been performed in the context of research on the immunomodulatory effects of intravenous immunoglobulin (IVIG). Among others, IVIG inhibits the differentiation, maturation and functions of dendritic cells (DC), thereby suppressing T-cell activation. In addition, IVIG stimulates expansion and suppressive function of regulatory T cells (Treg) carrying the antigens CD4, CD25 and Foxp3. Current data on the immunomodulatory effects of IVIG on DC and Treg are summarized, and possible molecular interactions between NAbs and DC or Treg that mediate these effects are discussed.

Regulation of immunity and inflammation by intravenous immunoglobulin: relevance to solid organ transplantation

Intravenous immunoglobulin (IVIg) products are derived from pooled human plasma from thousands of donors and have been used for the treatment of primary immunodeficiency disorders for more than 30 years. IVIg products are also effective in the treatment of autoimmune and inflammatory disorders, however, the precise mechanism(s) of action are not known. Recent data suggest that IVIg has a much broader ability to regulate cellular immunity, including innate and adaptive components. IVIg-induced upregulation of Fcγ receptor IIB on B cells appears to be an important mode of action in suppression of antigen-presenting cell activity and antibody production. IVIg is also a recently recognized modifier of complement activation and injury. Analysis of clinical studies examining the use of IVIg in desensitization protocols and for treatment of antibody-mediated rejection in transplant recipients are supportive. Here, we discuss these important advancements and their relevance to transplant medicine.

Prevention and treatment of alloantibody-mediated kidney transplant rejection

Antibody-mediated rejection (AMR), which is commonly caused by preformed and/or de novo HLA alloantibodies, has evolved as a leading cause of early and late kidney allograft injury. In recent years, effective treatment strategies have been established to counteract the deleterious effects of humoral alloreactivity. One major therapeutic challenge is the barrier of a positive pretransplant lymphocytotoxic crossmatch. Several apheresis- and/or IVIG-based protocols have been shown to enable successful crossmatch conversion, including a strategy of peritransplant immunoadsorption for rapid crossmatch conversion immediately before deceased donor transplantation. While such protocols may increase transplant rates and allow for acceptable graft survival, at least in the short-term, it has become evident that, despite intense treatment, many patients still experience clinical or subclinical AMR. This reinforces the need for innovative strategies, such as complementary allocation programs to improve transplant outcomes. For acute AMR, various studies have suggested efficiency of plasmapheresis- or immunoadsorption-based protocols. There is, however, no established treatment for chronic AMR and the development of strategies to reverse or at least halt chronic active rejection remains a big challenge. Major improvements can be expected from studies evaluating innovative therapeutic concepts, such as proteasome inhibition or complement blocking agents.

Acute antibody-mediated rejection in paediatric renal transplant recipients

Acute antibody-mediated rejections (aAMR) after renal transplantation are defined by rapidly deteriorating graft function, detection of donor-specific antibodies (DSA) and characteristic histological features. In adults, anti-rejection strategies comprise intravenous immunoglobulin (IVIG), steroid pulses, plasmapheresis and rituximab. Data of children with aAMR are scarce. We report four episodes of aAMR in three children (aged 10, 10 and 11 years respectively) occurring early after renal transplantation. Pre-transplant complement-dependent cytotoxicity crossmatches were negative; in the case of re-transplantation repeated antigens were excluded. Basic immunosuppression comprised cyclosporine A, MMF and steroids. All four rejection episodes were histologically proven and associated with acute renal failure. De novo DSAs were detected in two aAMRs; one patient was additionally tested positive for AT1-receptor antibodies. All aAMRs were treated with steroid pulses, tacrolimus, MMF, IVIG, plasmapheresis and one single dose of rituximab. Despite therapy one graft was lost; in the remaining three cases kidney function re-established within 1-8 weeks. At follow-up, 14, 15 and 22 months' post-rejection their GFRs were 65, 88 and 105 ml/min/1.73 m(2) respectively. A combined therapy of steroid pulses, IVIG, plasmapheresis and rituximab is potentially effective in the treatment of aAMR in children.

Desensitization: achieving immune detente

Antibodies to donor HLA (human leukocyte antigen) and/or ABO antigens were a contraindication to transplantation of most organs for decades. Desensitization protocols have shown the ability to produce reduction of such antibodies sufficient to achieve a successful transplantation. The two major protocols in use are high-dose IVIg or plasmapheresis with low-dose IVIg. The protocols differ in the basic treatment and, to some degree, in their application, but both use standard immunosuppressive agents as well as more recently developed adjunctive agents such as cell-depleting antibodies. Graft and patient survival with both types of protocol are comparable to that of non-sensitized patients, although desensitized patients do have a higher incidence of antibody-mediated rejection (AMR). Antibodies to donor antigens may persist after transplantation, and while the initial antibody titer represents the level of difficulty for successful desensitization, the strength of antibodies that persist after transplantation reflects the risk of AMR. Current protocols do not eliminate B cell clones specific for donor HLA; therefore, desensitized patients remain at an increased risk of antibody rebound if patients experience pro-inflammatory events. Therefore, ongoing antibody monitoring is crucial for early detection of antibody-mediated graft injury. Importantly, the results of numerous programs show that ABOi- and HLA-positive crossmatch renal transplantation, with proper desensitization, can be performed successfully. Further, in addition to increasing the rate of transplantation among sensitized patients, desensitization is providing insight into immunoregulatory processes and may provide information useful in diseases involving immune dysfunction.

Clinical aspects of intravenous immunoglobulin use in solid organ transplant recipients

Intravenous immunoglobulin products (IVIG) are derived from pooled human plasma from thousands of donors and have been used for the treatment of primary immunodeficiency disorders for nearly 30 years. IVIG products are also effective in the treatment of autoimmune and inflammatory disorders, however the precise mechanism(s) of immune modulation are unknown. Recent data suggests that IVIG has a much broader ability to regulate cellular immunity, including innate and adaptive components. IVIG is also a recently recognized modifier of complement activation and injury. These attributes suggests IVIG would have clinical applications in solid organ transplantation. Analysis of clinical studies examining the use of IVIG in desensitization protocols and for treatment of antibody-mediated rejection (AMR) are supportive for kidney transplant recipients, although no clinical trials using IVIG in sensitized patients were performed seeking an Federal Drug Administration indication. Data regarding the use of IVIG for desensitization and treatment of AMR in cardiac and lung allograft recipients is not conclusive. IVIG is useful in the treatment and prevention of posttransplant infectious complications including cytomegalovirus, parvovirus B19 and polyoma BK virus. In addition, we address the risk of adverse events associated with IVIG use in sensitized end-stage renal disease and transplant patients.

Advances in diagnosing and managing antibody-mediated rejection

Antibody-mediated rejection (AMR) is a unique, significant, and often severe form of allograft rejection that is not amenable to treatment with standard immunosuppressive medications. Significant advances have occurred in our ability to predict patients at risk for, and to diagnose, AMR. These advances include the development of newer anti-human leukocyte antigen (HLA)-antibody detection techniques and assays for non-HLA antibodies associated with AMR. The pathophysiology of AMR suggests a prime role for antibodies, B cells and plasma cells, but other effector molecules, especially the complement system, point to potential targets that could modify the AMR process. An emerging and potentially larger problem is the development of chronic AMR (CAMR) resulting from de novo donor-specific anti-HLA antibodies (DSA) that emerge more than 100 days posttransplantation. Therapeutic options include: (1) High-dose intravenously administered immunoglobulin (IVIG), which has many potential benefits. (2) The use of IVIG+rituximab (anti-CD20, anti-B cell). (3) The combination of plasmapheresis (PP)+low-dose IVIG with or without rituximab. Data support the efficacy of all of the above approaches. Newer approaches to treating AMR include using the proteosome inhibitor (bortezomib), which induces apoptosis in plasma cells, and eculizumab (anti-C5, anticomplement monoclonal antibody).

Use of intravenous immune globulin and rituximab for desensitization of highly HLA-sensitized patients awaiting kidney transplantation

BACKGROUND.: We have shown that high-dose intravenous immune globulin (IVIG; 2 g/kg x2 doses)+rituximab (1 g x2 doses) was effective in lowering anti-human leukocyte antigen (HLA) antibodies and improving rates of transplantation. The aim of this report was to evaluate the efficacy of IVIG+rituximab on reduction of anti-HLA antibodies to a level that was permissive for living donor (LD) or deceased donor (DD) transplantation without incurring the risk of antibody-mediated rejection and immediate graft loss. METHODS.: From July 2006 to February 2009, 76 HLA-sensitized (HS) patients who met strict sensitization criteria received kidney transplants after desensitization using IVIG 2 g/kg (days 1 and 30)+rituximab (1 g, day 15). Parameters evaluated included rates of transplantation, previous transplants, panel reactive antibodies, donor specific antibody, crossmatches (CMXs), patient and graft survival, acute rejection, serum creatinines, and infections. RESULTS.: Seventy-six HS CMX treated patients (31 LD/45 DD) were transplanted. For LD and DD recipients, significant reductions were seen in T-cell flow cytometry CMXs from pretreatment (T cell 183.5+/-98.4 mean channel shifts (MCS) for LD and 162.8+/-41 MCS for DD) to time of transplant (T cell 68.2+/-58 MCS for LD [P<0.00006] and 125+/-49 for DD [P=0.05]), respectively. Time on wait list for DD recipients was reduced from 95+/-46 months to 4.2+/-4.5 months after treatment. Twenty-eight patients (37%) experienced acute rejection (29% C4d/8% C4d). Patient and graft survival up to 24 months was 95% and 84%, respectively. The mean serum creatinines, at 12 and 24 months were 1.5+/-1.1 and 1.3+/-0.3 mg/dL, respectively. Viral infections were seen in six patients. CONCLUSIONS.: IVIG and rituximab seems to offer significant benefits in reduction of anti-HLA antibodies allowing improved rates of transplantation for HS patients, especially those awaiting DD, with acceptable antibody-mediated rejection and survival rates at 24 months.

The use of immunoglobulin therapy for patients undergoing solid organ transplantation: an evidence-based practice guideline

This guideline for the use of immunoglobulin (IG) for sensitized patients undergoing solid organ transplantation (SOT) is an initiative of the Canadian Blood Services and the National Advisory Committee on Blood and Blood Products of Canada to (1) provide guidance for Canadian practitioners involved in the care of patients undergoing SOT and transfusion medicine specialists on the use of IG and (2) standardize care, limit adverse events, and optimize patient care. A systematic expert and bibliography literature search up to July 2008 was conducted, with 791 literature citations and 45 reports reviewed. To validate the recommendations, the guideline was sent to physicians involved in SOT in Canada and a patient representative. The recommendations identify (1) sensitized patients undergoing SOT that would have a better survival and decreased morbidity by receiving IG preoperatively, postoperatively, and for the treatment of organ rejection; (2) patients who may not have any benefit from receiving IG; and (3) potential adversities to IG.

Intravenous immunoglobulin a natural regulator of immunity and inflammation

Intravenous immunoglobulin (IVIG) products are derived from pooled human plasma and have been used for the treatment of primary immunodeficiency disorders for more than 25 years. IVIG products are also effective in the treatment of autoimmune and inflammatory disorders; however, the precise mechanism(s) of action is not known. Recent investigations suggest that IVIG has a much broader ability to regulate cellular immunity including innate and adaptive components. IVIG is also a recently recognized modifier of complement activation and injury. Here, we discuss these important advancements and how this knowledge applies to desensitization protocols and to the treatment of antibody-mediated rejection.