Induction therapy by anti-thymocyte globulin (rabbit) in renal transplantation: a 1-yr follow-up of safety and efficacy

Effects of Induction Therapy on Graft Functions in Terms of Immunologic Risk

BACKGROUND

Advances in immunosuppressive therapies and surgical techniques have led to a significant reduction in the incidence of rejection within 1 year after kidney transplantation. Immunologic risk is an important factor affecting graft functions and guiding the clinician in the selection of induction therapy. The aim of this study was to investigate graft functions based on serum creatinine levels, Chronic Kidney Disease Epidemiology Collaboration (CKD- EPI) and proteinuria levels, frequency of leukopenia, cytomegalovirus (CMV) and BK virus polymerase chain reaction (PCR) positivity in patients with low and high immunologic risk.

MATERIAL AND METHODS

This retrospective study included 80 renal recipients. Recipients were divided into 2 groups: patients at low immunologic risk who received basiliximab only and those with high immunologic risk who received low-dose (1.5 mg/kg for 3 days) antithymocyte globulin and basiliximab.

RESULTS

No significant differences were observed between the 2 risk groups in terms of first, third, sixth, and 12th-month creatinine levels, CKD-EPI, proteinuria levels, leukopenia frequency, and CMV and BK virus PCR positivity.

CONCLUSION

One-year graft survivals did not differ significantly between these 2 treatment modalities. The combined use of low-dose antithymocyte globulin and basiliximab in the induction treatment of patients with high immunologic risk seems promising in terms of graft survival, leukopenia frequency, and CMV and BK virus PCR positivity.

Therapy in the Course of Kidney Graft Rejection-Implications for the Cardiovascular System-A Systematic Review

Kidney graft failure is not a homogenous disease and the Banff classification distinguishes several types of graft rejection. The maintenance of a transplant and the treatment of its failure require specific medications and differ due to the underlying molecular mechanism. As a consequence, patients suffering from different rejection types will experience distinct side-effects upon therapy. The review is focused on comparing treatment regimens as well as presenting the latest insights into innovative therapeutic approaches in patients with an ongoing active ABMR, chronic active ABMR, chronic ABMR, acute TCMR, chronic active TCMR, borderline and mixed rejection. Furthermore, the profile of cardiovascular adverse effects in relation to the applied therapy was subjected to scrutiny. Lastly, a detailed assessment and comparison of different approaches were conducted in order to identify those that are the most and least detrimental for patients suffering from kidney graft failure.

Complications of rabbit anti-thymocyte globulin induction immunosuppression in HIV-infected kidney transplant recipients

Background

Kidney transplantation in HIV-infected individuals with end-stage kidney disease is associated with improved survival compared to dialysis. Rabbit anti-thymocyte globulin (rATG) induction in HIV-infected kidney transplant recipients has been associated with a lower risk of acute rejection, but data on the rates of de novo malignancy and BK viremia in these patients is lacking.

Methods

We performed a single-center retrospective cohort study of adult HIV-infected individuals who underwent kidney transplantation with rATG induction between January 2006 and December 2016. The primary outcome was the development of de novo malignancy. Secondary outcomes included the development of BK viremia, infections requiring hospitalization, HIV progression, biopsy-proven acute rejection, and patient and allograft survival.

Results

Twenty-seven HIV-infected individuals with end-stage kidney disease received deceased (n=23) or living (n=4) donor kidney transplants. The cumulative rate of malignancy at five years was 29%, of whom 29% died because of advanced malignancy. BK viremia was detected in six participants (22%), of whom one had biopsy-proven BK virus-associated nephropathy and all of whom cleared the BK viremia. Five-year acute rejection rates, patient survival and death-censored allograft survival were 17%, 85% and 80% respectively.

Conclusion

rATG induction in HIV-infected kidney transplant recipients was associated with a low risk of acute rejection, but a potentially higher risk of de novo malignancies and BK viremia in this cohort. Screening strategies to closely monitor for BK virus infection and malignancy post-transplantation may improve outcomes in HIV-infected kidney transplant recipients receiving rATG induction.

Neutropenia in pediatric solid organ transplant

Neutropenia is generally defined as an absolute neutrophil count in the circulation of less than 1500/mm³ and occurs in up to 25%-30% of pediatric solid organ transplant recipients (SOT) within the first year after transplantation. In the SOT population, neutropenia is most often a result of drug-induced bone marrow suppression but can also be secondary to viral infection, nutritional deficiencies, lymphoproliferative infiltrate, and inherited causes. Outcomes for patients with neutropenia vary by degree of neutropenia and type of solid organ transplant. Management of neutropenia should begin by addressing the underlying cause, including reducing or removing medications when appropriate, treating infections, and addressing nutrient deficiencies; however, consultation with an experienced pediatric hematologist and use of granulocyte colony-stimulating factor (G-CSF) may be helpful in some cases. Overall, data on clinical outcomes for G-CSF use remain limited, but observational studies may support its use in patients with infections or severe neutropenia.

Comparison of Alemtuzumab and Anti-thymocyte Globulin Treatment for Acute Kidney Allograft Rejection

Rabbit anti-thymocyte globulin (rATG) is currently the treatment of choice for glucocorticoid-resistant, recurrent, or severe acute allograft rejection (AR). However, rATG is associated with severe infusion-related side effects. Alemtuzumab is incidentally given to kidney transplant recipients as treatment for AR. In the current study, the outcomes of patients treated with alemtuzumab for AR were compared with that of patients treated with rATG for AR. The patient-, allograft-, and infection-free survival and adverse events of 116 alemtuzumab-treated patients were compared with those of 108 patients treated with rATG for AR. Propensity scores were used to control for differences between the two groups. Patient- and allograft survival of patients treated with either alemtuzumab or rATG were not different [hazard ratio (HR) 1.14, 95%-confidence interval (CI) 0.48–2.69, p = 0.77, and HR 0.82, 95%-CI 0.45–1.5, p = 0.52, respectively). Infection-free survival after alemtuzumab treatment was superior compared with that of rATG-treated patients (HR 0.41, 95%-CI 0.25–0.68, p < 0.002). Infusion-related adverse events occurred less frequently after alemtuzumab treatment. Alemtuzumab therapy may therefore be an alternative therapy for glucocorticoid-resistant, recurrent, or severe acute kidney transplant rejection.

Antithymocyte globulin in pediatric allogeneic hematopoietic stem cell transplantation: Infusion time and tolerability

Antithymocyte globulin is a major drug in transplantation. rATG has been successfully used to prevent graft-versus-host disease in allogeneic HSCT. However, its first infusion is associated with reactions ranging from simple fevers to distributive shocks and may interfere with the transplant conditioning. To evaluate the impact of rATG infusion rate on clinical tolerability, we conducted a retrospective study of all pediatric allogeneic HSCT patients who received rATG (Thymoglobulin®) as part of their conditioning at Lille University Hospital from 2003 to 2018. Until 2012, patients received rATG with a theoretical infusion time of 12 hours (12H group, n = 33). From 2012, they had a theoretical infusion time of 4 hours (4H group, n = 43). Patients from the 12H arm presented more ≥ grade 3 infusion-related reactions at first dose (70% versus 44%, P = .027), had significantly higher fever (median of 39.6°C versus 39.2°C, P = .002), and needed a greater use of symptomatic treatments. However, they received a slightly higher first dose of rATG (median of 2.7 versus 2.3 mg/kg, P = .042). In view of these results, a rATG infusion time of 4 hours can be a relevant option for pediatric transplant centers to avoid interference with the conditioning regimen and facilitate medical surveillance.

Rabbit antithymocyte globulin for the treatment of chronic lung allograft dysfunction

BACKGROUND

Chronic lung allograft dysfunction (CLAD) is the leading cause of death beyond the first year after lung transplantation. Several treatments have been used to prevent the progression or reverse the effects of CLAD. Cytolytic therapy with rabbit antithymocyte globulin (rATG) has previously shown to be a potential option. However, the effect on patients with restrictive allograft syndrome (RAS) versus bronchiolitis obliterans syndrome (BOS) and the effect of cumulative dosing are unknown.

METHODS

The charts of lung transplant patients treated with rATG at Barnes-Jewish Hospital from 2009 to 2016 were retrospectively reviewed. The primary outcome was response to rATG; patients were deemed responders if their FEV₁ improved in the 6 months after rATG treatment. Safety endpoints included incidence of serum sickness, cytokine release syndrome, malignancy, and infectious complications.

RESULTS

108 patients were included in this study; 43 (40%) patients were responders who experienced an increase in FEV₁ after rATG therapy. No predictors of response to rATG therapy were identified. Serum sickness occurred in 22% of patients, 15% experienced cytokine release syndrome, and 19% developed an infection after therapy.

CONCLUSION

40% of patients with CLAD have an improvement in lung function after treatment with rATG although the improvement was typically minimal.

Burden of cytomegalovirus reactivation post kidney transplant with antithymocyte globulin use in Thailand: A retrospective cohort study

Background: Cytomegalovirus (CMV) is an important cause of infectious complications after kidney transplantation (KT), especially among patients receiving antithymocyte globulin (ATG). CMV infection can result in organ dysfunction and indirect effects such as graft rejection, graft failure, and opportunistic infections . Prevention of CMV reactivation includes pre-emptive or prophylactic approaches. Access to valganciclovir prophylaxis is limited by high cost. Our objective is to determine the burden and cost of treatment for CMV reactivation/disease among KT recipients who received ATG in Thailand since its first use in our center. Methods: We conducted a single-center retrospective cohort study of KT patients who received ATG during 2010-2013. We reviewed patients' characteristics, type of CMV prophylaxis, incidence of CMV reactivation, and outcome (co-infections, graft function and death). We compared the treatment cost between patients with and without CMV reactivation. Results: Thirty patients included in the study had CMV serostatus D+/R+. Twenty-nine patients received intravenous ganciclovir early after KT as inpatients. Only three received outpatient valganciclovir prophylaxis. Incidence of CMV reactivation was 43%, with a median onset of 91 (range 23-1007) days after KT. Three patients had CMV end-organ disease; enterocolitis or retinitis. Infectious complication rate among ATG-treated KT patients was up to 83%, with a trend toward a higher rate among those with CMV reactivation ( P = 0.087). Patients with CMV reactivation/disease required longer duration of hospitalization ( P = 0.018). The rate of graft loss was 17%. The survival rate was 97%. The cost of treatment among patients with CMV reactivation was significantly higher for both inpatient setting ( P = 0.021) and total cost ( P = 0.035) than in those without CMV reactivation. Conclusions: Burden of infectious complications among ATG-treated KT patients was high. CMV reactivation is common and associated with longer duration of hospitalization and higher cost.

Pulmonary Infections in Immunocompromised Hosts: Clinical

Pulmonary infections in immunocompromised patients remain a significant contributor to mortality, morbidity, and health care-associated costs in such a vulnerable patient population. Their epidemiology is changing, set forth by new trends in immunosuppressive regimens and also prophylaxis. The host characteristics, presenting clinical symptomatology, along with radiographic patterns, have also evolved. The microbiology diagnostics are now enriched with nonculture methods for better identification of the causative pathogens. Chest imaging remains the cornerstone of the initial workup. Our article will examine the new trends in epidemiology, clinical findings, and diagnostics for immunocompromised patients with pulmonary infections (transplant recipients, neutropenic hosts, HIV-infected patients, and patients with autoimmune conditions). We will also review the differential diagnosis that most of the times includes malignancies and drug or radiation-related toxicities.

The Efficacy of Rabbit Anti-Thymocyte Globulin for Acute Kidney Transplant Rejection in Patients Using Calcineurin Inhibitor and Mycophenolate Mofetil-Based Immunosuppressive Therapy

Background

T cell depleting antibody therapy with rabbit anti-thymocyte globulin (rATG) is the treatment of choice for glucocorticoid-resistant acute kidney allograft rejection (AR) and is used as first-line therapy in severe AR. Almost all studies investigating the effectiveness of rATG for this indication were conducted at the time when cyclosporine A and azathioprine were the standard of care. Here, the long-term outcome of rATG for AR in patients using the current standard immunosuppressive therapy (i.e., tacrolimus and mycophenolate mofetil) is described.

Material/Methods

Between 2002 to 2012, 108 patients were treated with rATG for AR. Data on kidney function in the year following rATG and long-term outcomes were collected.

Results

Overall survival after rATG was comparable to overall survival of all kidney transplantation patients (P=0.10). Serum creatinine 1 year after rATG was 179 μmol/L (interquartile range (IQR) 136–234 μmol/L) and was comparable to baseline serum creatinine (P=0.22). Early AR showed better allograft survival than late AR (P=0.0007). In addition, 1 year after AR, serum creatinine was lower in early AR (157 mol/L; IQR 131–203) compared to late AR (216 mol/L; IQR 165–269; P<0.05). The Banff grade of rejection, kidney function at the moment of rejection, and reason for rATG (severe or glucocorticoid resistant AR) did not influence the allograft survival.

Conclusions

Treatment of AR with rATG is effective in patients using current standard immunosuppressive therapy, even in patients with poor allograft function. Early identification of AR followed by T cell depleting treatment leads to better allograft outcomes.

Efficacy of antithymocyte globulin for allogeneic hematopoietic cell transplantation: a systematic review and meta-analysis

The efficacy of rabbit antithymocyte globulin (ATG) for the prevention of graft-versus-host disease (GVHD) has been evaluated in several randomized control trials, but the results show some discrepancies. Therefore, we performed a systematic review and meta-analysis covering the latest RCTs including six trials (total 845 patients). The incidence of acute and chronic GVHD was significantly lower in the ATG arms (risk ratio, 0.75 and 0.54, respectively). No significant differences were found regarding overall survival, the incidence of relapse, and non-relapse mortality; however, the incidence of cytomegalovirus and Epstein-Barr virus reactivation increased (risk ratio, 1.25 and 1.33), and neutrophil engraftment was significantly delayed (median, 2.66 days). In conclusion, rabbit ATG should be beneficial as a GVHD prophylaxis in addition to conventional regimens, with close monitoring of virus reactivation and enough attention to delayed engraftment. Studies comparing the timing and dosage of ATG are essential to determine the suitable prophylactic regimens.

Immunosuppressive Medications

Immunosuppressive agents are commonly used in the nephrologist's practice in the treatment of autoimmune and immune-mediated diseases and transplantation, and they are investigational in the treatment of AKI and ESRD. Drug development has been rapid over the past decades as mechanisms of the immune response have been better defined both by serendipity (the discovery of agents with immunosuppressive activity that led to greater understanding of the immune response) and through mechanistic study (the study of immune deficiencies and autoimmune diseases and the critical pathways or mutations that contribute to disease). Toxicities of early immunosuppressive agents, such as corticosteroids, azathioprine, and cyclophosphamide, stimulated intense investigation for agents with more specificity and less harmful effects. Because the mechanisms of the immune response were better delineated over the past 30 years, this specialty is now bestowed with a multitude of therapeutic options that have reduced rejection rates and improved graft survival in kidney transplantation, provided alternatives to cytotoxic therapy in immune-mediated diseases, and opened new opportunities for intervention in diseases both common (AKI) and rare (atypical hemolytic syndrome). Rather than summarizing clinical indications and clinical trials for all currently available immunosuppressive medications, the purpose of this review is to place these agents into mechanistic context together with a brief discussion of unique features of development and use that are of interest to the nephrologist.

Safety of mTOR inhibitors in adult solid organ transplantation

INTRODUCTION

Mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) are a class of immunosuppressive drugs approved for solid organ transplantation (SOT). By inhibiting the ubiquitous mTOR pathway, they present a peculiar safety profile. The increased incidence of serious adverse events in early studies halted the enthusiasm as a kidney sparing alternative to calcineurin inhibitors (CNI).

AREAS COVERED

Herein we review mTOR inhibitors safety profile for adult organ transplantation, ranging from acute side effects, such as lymphoceles, delayed wound healing, or cytopenias, to long-term ones which increase morbidity and mortality, such as cancer risk and metabolic profile. Infection, proteinuria, and cutaneous safety profiles are also addressed.

EXPERT OPINION

In the authors' opinion, mTOR inhibitors are a safe alternative to standard immunosuppression therapy with CNI and mycophenolate/azathioprine. Mild adverse events can be easily managed with an increased awareness and close monitoring of trough levels. Most serious side effects are dose- and organ-dependent. In kidney and heart transplantation mTOR inhibitors may be safely used as either low-dose de novo or through early-conversion. In the liver, conversion 4 weeks post-transplantation may reduce long-term chronic kidney disease secondary to calcineurin nephrotoxicity, without increasing hepatic artery/portal vein thrombosis.

Human Leukocyte Antigen Alleles and Cytomegalovirus Infection After Renal Transplantation

Background:

Several studies have been conducted on the relationship between a number of human leukocyte antigen (HLA) alleles and cytomegalovirus infection (CMV), in kidney transplant recipients, after transplantation. However, only a limited number of HLAs have been investigated, so far, and the results have been contradictory.

Objectives:

This study aimed to investigate the relationship between 59 HLA alleles and the CMV infection, in transplant recipients, after kidney transplantation.

Patients and Methods:

This retrospective cohort study was conducted on 200 patients, receiving a kidney transplant, in Baqiyatallah Hospital, in Tehran, during 2013. Throughout a one-year follow-up of kidney transplant recipients, in case of detecting the CMV antigen in patients’ blood, at any time, they were placed in the group of patients with CMV infection, whereas, if no CMV-specific antigen was developed, over a year, patients were placed in the group of patients without CMV infection, after transplantation. This study investigated the relationship between CMV infection in kidney transplant recipients and 59 HLA alleles, including 14 HLA-A, 28 HLA-B, and 17 HLA-DRB1 cases.

Results:

Of all participants, 104 patients (52%) were diagnosed with CMV infection. There was no significant difference between the two groups, with and without CMV infection, in terms of patient’s characteristics. The CMV infection, in patients receiving a transplanted organ from deceased donor, was significantly more prevalent than in those receiving kidney transplant from living donor (63% vs. 39%, respectively, P = 0.001). Recipients with HLA-B44 were more infected with CMV compared with patients without this allele (80% vs. 50%, respectively, P = 0.024); on the contrary, kidney recipients with HLA-DRB1-1 were less infected with CMV than patients without this allele (31% vs. 55%, respectively, P = 0.020). There was no significant relationship between CMV infection and other HLA alleles. Results of multivariate logistic regression analysis showed that deceased donor renal transplantation (OR = 3.018, 95%CI: 1.662 - 5.480, P < 0.001), presence of HLA-B44 (OR = 4.764, 95%CI: 1.259 - 18.032, P = 0.022) and lack of HLA-B8 (OR = 3.246, 95%CI: 1.030 - 10.230, P = 0.044) were the independent risk factors for developing CMV infection, after kidney transplantation.

Conclusions:

The findings of this study showed that deceased donor renal transplantation and the presence of HLA-B44 can make the kidney recipient susceptible to CMV infection after kidney transplantation; on the other hand, the presence of HLA-B8 can have a protective effect.

New directions for rabbit antithymocyte globulin (Thymoglobulin(®)) in solid organ transplants, stem cell transplants and autoimmunity

In the 30 years since the rabbit antithymocyte globulin (rATG) Thymoglobulin^® was first licensed, its use in solid organ transplantation and hematology has expanded progressively. Although the evidence base is incomplete, specific roles for rATG in organ transplant recipients using contemporary dosing strategies are now relatively well-identified. The addition of rATG induction to a standard triple or dual regimen reduces acute cellular rejection, and possibly humoral rejection. It is an appropriate first choice in patients with moderate or high immunological risk, and may be used in low-risk patients receiving a calcineurin inhibitor (CNI)-sparing regimen from time of transplant, or if early steroid withdrawal is planned. Kidney transplant patients at risk of delayed graft function may also benefit from the use of rATG to facilitate delayed CNI introduction. In hematopoietic stem cell transplantation, rATG has become an important component of conventional myeloablative conditioning regimens, following demonstration of reduced acute and chronic graft-versus-host disease. More recently, a role for rATG has also been established in reduced-intensity conditioning regimens. In autoimmunity, rATG contributes to the treatment of severe aplastic anemia, and has been incorporated in autograft projects for the management of conditions such as multiple sclerosis, Crohn’s disease, and systemic sclerosis. Finally, research is underway for the induction of tolerance exploiting the ability of rATG to induce immunosuppresive cells such as regulatory T-cells. Despite its long history, rATG remains a key component of the immunosuppressive armamentarium, and its complex immunological properties indicate that its use will expand to a wider range of disease conditions in the future.

Ruling out false-positive urinary Legionella pneumophila serogroup 1 and Streptococcus pneumoniae antigen test results by heating urine

We report here false-positive urinary Legionella pneumophila serogroup 1 and Streptococcus pneumoniae antigen test results due to rabbit antilymphocyte serum treatment and provide a simple and fast solution to rule them out by heating urine.

Prevention and management of cytomegalovirus infection in solid-organ transplantation

Cytomegalovirus (CMV) is the most common opportunistic viral infection to occur following solid-organ transplantation. This review will discuss the current strategies of management of CMV in solid-organ transplantation and their challenges. There are two principal approaches for preventing CMV disease in recipients of solid-organ transplants: prophylactic and pre-emptive. Ganciclovir is the most studied and used antiviral for both treatment and prevention, and is the first-line treatment for CMV infection and CMV disease in transplant recipients. There is no consensus regarding the most appropriate prevention method and the approach to CMV disease prevention differs among transplantation centers owing to the paucity of data comparing the two strategies head-to-head. Currently, the recommended treatment for CMV disease is intravenous ganciclovir.

Risk factors for impaired CD4+ T-cell reconstitution following rabbit antithymocyte globulin treatment in kidney transplantation

To describe long-term CD4⁺ T-cell reconstitution after rabbit antithymocyte globulin (rATG) treatment and identify predictive factors following kidney transplantation. A single-center retrospective study analyzed lymphocyte subsets in rATG-treated kidney transplant recipients (1986–2009). 589 patients were analyzed (maximum follow-up 21 years). A comparator group (n = 298) received an anti-IL-2 receptor monoclonal antibody. CD4⁺ T-cell lymphopenia (<200/mm³) was present in 48.5%, 9.2%, 6.7%,2.0%, and 0% of patients at one, three, five, 10, and 20 years post-transplant, respectively. CD4⁺ T-cell count increased during the first 10 years but remained below the pretransplant count even after 20 years. At 1, 3, and 6 months post-transplant, mean CD4⁺ T-cell count was significantly lower in patients with CD4⁺ T-cell lymphopenia at 12 months versus patients without lymphopenia. On multivariate analyses, significant independent predictors for long-term impaired CD4 T-cell reconstitution were recipient age, pretransplant CD4⁺ T-cell count, 12-month CD4⁺ T-cell count, and tacrolimus or MMF therapy. Recipient age >40 years was identified as a cutoff point. CD4⁺ T-cell reconstitution following rATG treatment remains impaired even after 21 years. Most risk factors for long-term impaired CD4⁺ T-cell reconstitution may be evaluated pretransplant or are modifiable post-transplant.

Blood disorders after kidney transplantation

Post transplant anemia (PTA) is a common issue in kidney transplant recipients. Most importantly it is associated with an impaired allograft function. Other important factors associated with PTA are immunosuppressive drugs (MPA, AZA and SRL), iron deficiency, infections (Parvo B19), older donor age, rejection episodes, an increased inflammatory state, and erythropoietin hyporesponsiveness. As there are no adequately powered RCTs in the kidney transplant population on anemia treatment with ESA, we have to rely on what we know from the large RCTs in the CKD population. The recently published KDIGO guidelines do not recommend treatment with ESA if Hb is >10 g/dl. Repletion of iron stores is emphasized. Post transplant leukopenia (PTL) and thrombocytopenia (PTT) are frequent complications especially in the first six months after kidney transplantation. Myelosuppression caused by immunosuppressive agents (MPA, AZA, SRL, rATG), antimicrobial drugs (VGCV), and CMV infection is the predominant cause. There are no widely accepted guidelines on treatment strategies, but most often dose reduction or discontinuation of causative medication is done. Most clinicians tend to decrease MPA dose, but this is eventually associated with an increase in acute rejection episodes. VGCV dose reduction (preemptive treatment instead of CMV prophylaxis) may be a successful strategy. In severe cases G-CSF treatment is an important management option and seems to be safe.

The role of Thymoglobulin induction in kidney transplantation: an update

The rabbit antithymocyte globulin Thymoglobulin first became available over 25 yr ago and is the most widely used lymphocyte-depleting preparation in solid organ transplantation. Thymoglobulin targets a wide range of T-cell surface antigens as well as natural killer-cell antigens, B-cell antigens, plasma cell antigens, adhesion molecules and chemokine receptors, resulting in profound, long-lasting T-cell depletion. Randomized studies have established the anti-rejection efficacy of Thymoglobulin in kidney transplantation. Experimental and clinical data suggest that Thymoglobulin administration may ameliorate ischemia reperfusion injury, thus reducing the incidence of delayed graft function (DGF). Studies have demonstrated the benefit of using Thymoglobulin to facilitate immunosuppression minimization, both for corticosteroid and calcineurin inhibitor (CNI) withdrawal or avoidance, with potential improvement in cardiovascular and renal outcomes. The optimal cumulative dose for Thymoglobulin induction is 6-7.5 mg/kg, with vigilant short- and long-term monitoring of hematological status. Induction with Thymoglobulin is now indicated in immunologically high-risk patients, in those at increased risk of DGF and to maintain efficacy in low-risk transplant recipients receiving steroid or CNI minimization or avoidance regimens. We suggest that in future trials Thymoglobulin be tested with costimulation signal blockers and other immunosuppressants with the objective of establishing operational tolerance.

Selection of induction therapy in kidney transplantation

Currently available immunosuppressive agents can be classified into three categories: induction agents, maintenance therapy, and treatment for rejection. This review article will focus on induction immunosuppression. There are three antibodies which are used for induction therapy: the lymphocyte-depleting agents - anti-thymocyte globulin and alemtuzumab, and basiliximab which is nondepleting. Historically, immunosuppressant selection was solely based on efficacy for prevention of rejection. In the current era of transplantation, it is now common practice in the transplant community to select induction therapy on the basis of risk-benefit considerations for each patient. This article will focus on the efficacy of available induction agents and the selection of induction agent based on donor and recipient risk factors.

Severe anaphylactoid reaction to thymoglobulin in a pediatric renal transplant recipient

Intraoperative administration of thymoglobulin is an integral part of the anti-rejection regimen during organ transplantation. However, its administration may be associated with complications. An anaphylactoid reaction that occurred in a pediatric recipient of a living-related renal transplant, on initiating an intravenous infusion of thymoglobulin, is presented.

Serum sickness following rabbit anti-thymocyte globulin for acute vascular renal allograft rejection

A simultaneous pancreas–kidney transplant recipient developed serum sickness manifesting with severe upper limb allodynia, arthralgia and myalgia 17 days following rabbit anti-thymocyte globulin (rATG) infusion for biopsy-proven vascular rejection. Rapid resolution of symptoms followed treatment with high-dose glucocorticoids. rATG is increasingly favoured over equine ATG in solid-organ transplantation, and although rATG has a superior safety profile, it is important to maintain a high index of suspicion for serum sickness.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Rabbit antithymocyte globulin (thymoglobulin): 25 years and new frontiers in solid organ transplantation and haematology

The more than 25 years of clinical experience with rabbit antithymocyte globulin (rATG), specifically Thymoglobulin, has transformed immunosuppression in solid organ transplantation and haematology. The utility of rATG has evolved from the treatment of allograft rejection and graft-versus-host disease to the prevention of various complications that limit the success of solid organ and stem cell transplantation. Today, rATG is being successfully incorporated into novel therapeutic regimens that seek to reduce overall toxicity and improve long-term outcomes. Clinical trials have demonstrated the efficacy and safety of rATG in recipients of various types of solid organ allografts, recipients of allogeneic stem cell transplants who are conditioned with both conventional and nonconventional regimens, and patients with aplastic anaemia. Over time, clinicians have learnt how to better balance the benefits and risks associated with rATG. Advances in the understanding of the multifaceted mechanism of action will guide research into new therapeutic areas and future applications.

Overview of immunosuppression in liver transplantation

Continued advances in surgical techniques and immunosuppressive therapy have allowed liver transplantation to become an extremely successful treatment option for patients with end-stage liver disease. Beginning with the revolutionary discovery of cyclosporine in the 1970s, immunosuppressive regimens have evolved greatly and current statistics confirm one-year graft survival rates in excess of 80%. Immunosuppressive regimens include calcineurin inhibitors, anti-metabolites, mTOR inhibitors, steroids and antibody-based therapies. These agents target different sites in the T cell activation cascade, usually by inhibiting T cell activation or via T cell depletion. They are used as induction therapy in the immediate peri- and post-operative period, as long-term maintenance medications to preserve graft function and as salvage therapy for acute rejection in liver transplant recipients. This review will focus on existing immunosuppressive agents for liver transplantation and consider newer medications on the horizon.

Significance of immune cell function monitoring in renal transplantation after Thymoglobulin induction therapy

Monitoring of immune status in transplant recipients is essential for predicting the risk of rejection or infection. In this study, we assessed the significance of immune cell function in 76 renal allograft recipients after Thymoglobulin induction and initiation of maintenance immunosuppression. Using the Immuknow (Cylex Inc) assay, the amount of adenosine triphosphate (ATP) produced by CD4+ cells in response to phytohemagglutinin (PHA) was measured in patients whole blood. In parallel, the frequency and phenotype of CD4+ T cells were determined by flow cytometry. The Immuknow assay yielded paradoxically high ATP values during the first 3 months post-transplantation, despite very low CD4+ T cell counts. High ATP values were caused by peripheral blood myeloid cells, did not predict rejection, and occurred primarily in transplant recipients who received darbepoietin (p = 0.017). CD4+ T cells displayed predominantly an activated/memory phenotype and comprised a subpopulation of CD25+FOXP3+ cells. Over the first 5 months post-transplantation, mean ATP activity gradually decreased, whereas CD4+ T cell counts slowly increased. Low ATP values were predictive of infection (p = 0.002). Thus Immuknow results need to be interpreted with caution in patients receiving Thymoglobulin induction therapy. Although low ATP levels identify patients at increased risk for infection, high ATP values fail to correlate with rejection and do not justify increased immunosuppression.

Management of leukopenia in kidney and pancreas transplant recipients

Leukopenia is frequently observed in the setting of solid organ transplantation. The risk factors, natural history, and outcomes associated with leukopenia post-transplantation have not been well defined. We retrospectively studied 102 adult kidney and/or pancreas transplant recipients over a one-yr period of time. By defining leukopenia as a white blood cell count < or =3000 cells/mm(3) and neutropenia as an absolute neutrophil count < or =2000/mm(3), the combined incidence of either leukopenia or neutropenia was 58% (59/102); the first episode occurred at a mean of 91 d post-transplant. A significant increase in the incidence of leukopenia was found in patients who either received alemtuzumab induction (42% with alemtuzumab vs. 9% with rabbit anti-thymocyte globulin induction, p < 0.05) and/or had rapid steroid withdrawal in the early post-transplant period (44% with vs. 16% without steroid withdrawal, p < 0.05). The most common intervention performed for leukopenia was reducing the dose of mycophenolate mofetil and/or valganciclovir. When granulocyte stimulating factors were used, a mean of 3.1 doses were needed to successfully manage the leukopenia. Although leukopenia was a common finding in our study of kidney and/or pancreas transplant recipients, there was no difference in the rates of infection or acute rejection in patients with and without leukopenia.

Thymoglobulin dose optimization for induction therapy in high risk kidney transplant recipients

BACKGROUND

Thymoglobulin (rATG) has become the agent of choice for induction therapy in high immunological risk kidney transplant recipients. However, its optimal dosing in this subgroup has not been studied.

METHODS

To evaluate the effect of total rATG dosing on graft outcomes in such patients, we conducted a retrospective cohort study of 96 adult patients who received repeat transplants (85%) or had panel reactive antibody more than 40% (19%) and were maintained on tacrolimus, mycophenolate mofetil, and steroid. Group 1 (n=33) received less than or equal to 7.5 and group 2 (n=63) received more than 7.5 mg/kg rATG. Graft and patient survival, incidence of acute rejection (AR), and 12-month serum creatinine (SCr) were examined.

RESULTS

The groups were comparable regarding demographics, donor source, retransplantation, panel reactive antibody, and human leukocyte antigen mismatch. Group 2 had more African Americans (44.4% vs. 21.2%, P=0.03). During the 25.4+/-18.0 months follow-up graft survival was 82.5% and 79.4%, respectively (P=0.54). Three in group 1 and four in group 2 died (P=0.65). The incidence of biopsy proven AR during the first 12-months did not differ between the groups (9.5% vs. 8.8%, respectively, P=0.9). SCr at 12 months was 1.6+/-0.7 in group 1 and 1.8+/-1.0 in group 2 (P=0.3). There was no independent association between rATG dose and graft survival (hazard ratio: 0.85, P=0.79, 95% CI: 0.26-2.7 for group 2 vs. 1) or 1-year SCr (regression coefficient=0.02 for ln(SCr), P=0.3; 95%CI: -0.01 to 0.6).

CONCLUSION

Our results suggest that in high risk kidney transplant recipients total rATG doses less than or equal to 7.5 mg/kg are safe and effective in achieving a low rate of AR and graft outcomes comparable to higher doses.

Comparison of outcomes with low-dose anti-thymocyte globulin, basiliximab or no induction therapy in pediatric kidney transplant recipients: a retrospective study

It is unclear which induction therapy yields the best outcomes in pediatric kidney transplantation. Retrospective data of 88 children receiving a renal allograft between November 1996 and October 2003 were analyzed. Patients received ATGI (n = 12), BI (n = 29), or NAI (n = 47). The mean ATG dose was 5.1 +/- 2.1 mg/kg. At 12 months, graft survival rates were 91.7%, 100%, and 97.9% for ATGI, BI, and NAI groups, respectively. Acute rejection rates at 12 months were 0 (ATGI), 20.6% (BI), and 10.7% (NAI). The mean GFR for ATGI (42.4 +/- 25.9 mL/min) was lower than for BI (78.3 +/- 27.2 mL/min), and NAI (66 +/- 28.3 mL/min) at 12 months (p < 0.05). One ATGI patient developed CMV pneumonia but none developed post-transplant lymphoproliferative disorder. Although there was no renal allograft survival benefit with either ATGI or BI, relative to NAI, the absence of acute rejection and equivalent rates of viral infections in the higher-risk ATGI recipient group suggests that the treatment strategy is promising. A large prospective study is needed to better define the role of ATGI in pediatric kidney transplantation.

Decreased incidence of acute rejection in adolescent kidney transplant recipients using antithymocyte induction and triple immunosuppression

BACKGROUND

Acute rejection is a frequent event in pediatric renal transplantation; it can diminish allograft function and affect long-term outcome. Recent data from the North American Pediatric Renal Transplant Cooperative Study indicates that the rate of acute rejection remains high despite current immunosuppressive regimens.

METHODS

In this retrospective series, we examined 37 pediatric renal transplant recipients who received induction doses of antithymocyte globulin combined with maintenance immunotherapy using tacrolimus, mycophenolate mofetil, and prednisone. The postoperative course was reviewed for initial and total hospital stay, number of rehospitalizations, evidence of posttransplant complications, graft fibrosis, and overall patient and graft survival.

RESULTS

Three episodes of acute rejection (8.1%) were recorded in the first year posttransplant. The median initial hospital stay for patients receiving a kidney transplant was 8 days. Patient and graft survival were 100% and 91.9% at 1 year, respectively. The incidence of viral infection (cytomegalovirus, BK virus, and Epstein-Barr virus) and posttransplant lymphoproliferative disease remained low. Urinary tract infection and fluid and electrolyte complications were the main causes of posttransplant hospitalization.

CONCLUSIONS

We conclude that induction with antithymocyte globulin and maintenance immunosuppression with tacrolimus, mycophenolate, and prednisone should be considered a valuable tool in the management of children undergoing renal transplantation.

Serum sickness following rabbit antithymocyte-globulin induction in a liver transplant recipient: case report and literature review

Thymoglobulin (Genzyme, Cambridge, MA) is an antithymocyte globulin preparation used for induction immunosuppression therapy in solid organ transplantation. It is being utilized with increasing frequency in orthotopic liver transplantation (OLT) in an effort to minimize or delay the use of calcineurin inhibitors due to their inherent nephrotoxicity. Experience with thymoglobulin in OLT remains limited. We report a case of serum sickness in a patient who received thymoglobulin following OLT. The patient experienced intermittent fevers, polyarthralgia, and acute renal failure 9 days after completion of thymoglobulin administration. The patient's symptoms resolved rapidly and completely with a course of intravenous steroids. We review a set of diagnostic criteria for serum sickness and emphasize the importance of early recognition of the process. Early treatment of serum sickness with steroids or plasmapheresis is highly effective and can reduce unnecessary morbidity from this unusual sequela of induction immunosuppression with antithymocyte globulin.

Acute sensory neuropathy associated with rabbit antithymocyte globulin

Rabbit antithymocyte globulin (RATG) is indicated for the treatment of acute renal transplant rejection and has also been shown to be effective as an induction immunosuppressive agent after renal transplantation. We report a patient that developed a painful sensory neuropathy within an hour of receiving RATG. The neuropathic symptoms resolved within a month, and a careful review of his medications, exposures and comorbid conditions revealed no other causes of neuropathy. Since the administration of RATG and onset of symptoms were so closely related temporally and the symptoms resolved after the cessation of RATG, we believe it is likely this medication led to the development of neuropathy.

Rabbit antithymocyte globulin induction therapy in adult renal transplantation

Rabbit antithymocyte globulin (rATG) and horse antithymocyte globulin (horse ATG) are the polyclonal antithymocyte agents available for use in solid organ transplantation in the United States. Horse ATG is indicated for induction immunosuppression and for treatment of acute rejection episodes after kidney transplantation; rATG is indicated for treatment of acute rejection only. However, rATG is commonly used in clinical practice as an induction immunosuppressive agent, instigating many questions regarding appropriate dosing, tolerability, safety, and efficacy. Available evidence supports the use of rATG as an induction agent in adult renal transplant recipients. The use of this product for induction therapy has been studied in conjunction with a full-dose, triple-therapy maintenance regimen (sequential quadruple immunosuppression) consisting of a calcineurin inhibitor, an antimetabolite, and corticosteroids. Rabbit ATG has a proven safety and efficacy profile both as treatment of acute rejection and as induction therapy in patients undergoing kidney transplantation. The most common adverse events associated with rATG are cytokine release syndrome, thrombocytopenia, and lymphopenia. Results of early studies showed an increased rate of cytomegalovirus disease associated with rATG treatment, but recent studies indicate that routine administration of modern antiviral prophylaxis can reduce this risk. Current practice with rATG is evolving to minimize lifelong exposure to calcineurin inhibitors and corticosteroids.