Thymoglobulin and rate of infectious complications after transplantation

First-in-human Study With LIS1, a Next-generation Porcine Low Immunogenicity Antilymphocyte Immunoglobulin in Kidney Transplantation

BACKGROUND

Polyclonal rabbit antithymocyte globulins (ATGs) are commonly used in organ transplantation as induction. Anti- N -glycolylneuraminic acid carbohydrate antibodies which develop in response to rabbit carbohydrate antigens might lead to unwanted systemic inflammation. LIS1, the first new generation of antilymphocyte globulins (ALGs) derived from double knockout swine, lacking carbohydrate xenoantigens was already tested in nonhuman primates and rodent models.

METHODS

This open-label, single-site, dose escalation, first-in-human, phase 1 study evaluated the safety, T cell depletion, pharmacokinetics, and pharmacodynamics of LIS1. In an ascending dose cohort (n = 5), a primary kidney transplant recipient at low immunologic risk (panel reactive antibody [PRA] < 20%), received LIS1 for 5 d at either 0.6, 1, 3, 6, or 8 mg/kg. After each patient completed treatment, the data safety monitoring board approved respective dose escalation. In the therapeutic dose cohort (n = 5) in patients with PRA <50% without donor specific antibodies, 2 patients received 8 mg/kg and 3 patients 10 mg/kg.

RESULTS

CD3 + T cell depletion <100/mm 3 at day 2 was observed in all patients who received 6, 8, and 10 mg/kg of LIS1. The terminal half-life of LIS1 was 33.7 d with linearity in its disposition. Lymphocyte repopulation was fast and pretransplant lymphocyte subpopulation counts recovered within 2-4 wk. LIS1 was well tolerated, neither cytokine release syndrome nor severe thrombocytopenia or leukopenia were noticed. Antibodies to LIS1 were not detected.

CONCLUSIONS

In this first-in-human trial, genome-edited swine-derived polyclonal LIS1 ALG was well tolerated, did not elicit antidrug antibodies, and caused time-limited T cell depletion in low- and medium-risk kidney transplant recipients.

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.

Single-dose antithymocyte globulin in standard immunological risk kidney transplant recipients: efficacy and kinetics of peripheral blood CD3+ T lymphocyte modulation

BACKGROUND

Polyclonal anti-T cell antibodies (ATG or thymoglobulin®) are used as induction therapy in kidney transplant recipients. This study evaluates the safety, efficacy, and CD3+ T lymphocyte modulation of two ATG regimens.

METHODS

The trial included two cohorts of kidney transplant recipients that were followed for one year. The study group, including standard immunological risk recipients, received one 3 mg/kg dose of ATG. The comparator group, including standard and high immunological risk kidney transplant recipients, received a fractionated dose regimen (up to four 1.5 mg/kg doses). Patient and graft outcomes and the kinetics of CD3+ T lymphocyte modulation in the peripheral blood were evaluated.

RESULTS

One hundred kidney transplant recipients were included in each group. The one-year incidence of treated acute rejection, and patient and graft survival did not differ between groups. Bacterial infections were significantly more frequent in fractionated-dose group patients (66% versus 5%; P = 0.0001). At one-year follow-up, there was no difference in the incidence of cytomegalovirus infection (P = 0.152) or malignancies (P = 0.312). CD3+ T lymphocyte immunomodulation in the single-dose group was more effective in the first two days after transplantation. After the third post-transplant day, CD3+ T lymphocyte modulation was more efficient in the fractionated dose group.

CONCLUSION

Both regimens resulted in low rejection rates and equivalent survival. The single and reduced dose regimen protects from the occurrence of bacterial infections. CD3+ T lymphocyte modulation occurred with different kinetics, although it did not result in distinct outcomes.

Induction and maintenance immunosuppression in pediatric kidney transplantation-Advances and controversies

Advances in immunosuppression have improved graft survival in pediatric kidney transplant recipients; however, treatment-related toxicities need to be balanced against the possibility of graft rejection. Several immunosuppressive agents are available for use in transplant recipients; however, the optimal combinations of agents remain unclear, resulting in variations in institutional protocols. Lymphocyte-depleting antibodies, specifically ATG, are the most common induction agent used for pediatric kidney transplantation in the US. Basiliximab may be used for induction in immunologically low-risk children; however, pediatric data are scarce. CNIs and antiproliferative agents (mostly Tac and mycophenolate in recent years) constitute the backbone of maintenance immunosuppression. Steroid-avoidance maintenance regimens remain controversial. Belatacept and mTOR inhibitors are used in children under specific circumstances such as non-adherence or CNI toxicity. This article reviews the indications, mechanism of action, efficacy, dosing, and side effect profiles of various immunosuppressive agents available for pediatric kidney transplantation.

Kidney Transplantation during the SARS-CoV-2 Pandemic in Israel: Experience from a Large-Volume Center

Coronavirus disease 2019 (COVID-19) has affected tens of millions of people globally since it was declared a pandemic by the World Health Organization on 11 March 2020. Since its outbreak in December 2019, the ongoing coronavirus COVID-19 pandemic has led to global social, economic and healthcare crises affecting millions of people and causing the death of hundreds of thousands of people worldwide. As with other fields of healthcare, the pandemic with its heavy workload imposed on hospital services and personnel significantly affected solid organ transplantation. Concerns for potential exposure to the virus and its related severe acute respiratory syndrome coronavirus type 2 (SARS-CoV2) have profoundly altered the process of organ donation and recovery, acceptance of organ offers, management of potential recipients and living donors, and above all transplanted and immunosuppressed patients. All those issues required prompt implementation of new practice measures and guidelines as well as continuous adaptations to the fluid and rapidly changing situation. Herein we describe a single transplant center experience with kidney transplantation during the COVID-19 pandemic; we review the national and institutional measures and restrictions undertaken in different phases of the ongoing event as well as the outcomes.

Antithymocyte induction dosing and incidence of opportunistic viral infections using steroid-free maintenance immunosuppression

BACKGROUND

Currently, there is limited literature evaluating rATG induction dosing and incidence of opportunistic viral infections when using steroid-free maintenance immunosuppression.

METHODS

This single-center, retrospective, study compared high rATG (>4.5 mg/kg) versus low (<4.5 mg/kg) induction dosing and the overall incidence of early opportunistic viral infection at 180 days in the setting of maintenance immunosuppression consisting of tacrolimus, mycophenolate, rapid steroid withdrawal, and a tiered antiviral prevention strategy based on donor-recipient Cytomegalovirus (CMV) serostatus.

RESULTS

A total of 209 patients were included; 76 patients received low-dose and 133 patients received high-dose rATG. Incidence of overall opportunistic viral infection occurred more frequently in patients who received high compared to low dose (29.8% vs 25% p = .030). Incidence of CMV infection was also significantly increased in the high-dose group (31.6% vs 18.4% p = .039). In a multivariable model, rATG dose, as a continuous variable, remained a significant independent predictor of infection along with CMV risk (OR 1.46, 95% CI 1.02-2.09) controlling for age and CMV risk. There were no differences in graft-related outcomes at 180 days.

CONCLUSION

Higher cumulative rATG induction dose was associated with increased incidence of opportunistic viral infections, in the setting of a steroid-free maintenance immunosuppression in the early post-transplant period.

Induction therapy in kidney transplant recipients: Description of the practices according to the calendar period from the French multicentric DIVAT cohort

Background

There is extensive literature with comparisons between Anti-Thymocyte Globulin (ATG) and Basiliximab (BSX) as induction therapy in kidney transplant recipients. The purpose of our benchmarking study was to describe the consequences in terms of practices in 6 transplantation centers of a French prospective cohort.

Methods

We included adult patients who received a first or second kidney graft between 2013 and 2019 (n = 4157). We used logistic regressions to identify characteristics associated with the use of ATG or BSX.

Results

Use of ATG between the centers ranged from 41% to 75%. We observed different factors associated with the treatment decision. Compared to a first transplant, performing a second graft was the only factor significantly associated with the choice of ATG in all centers. The AUC ranged from 0.67 to 0.91, indicating that the centers seemed to define their own rules. As a result, for patients with the same low immunological risk, the probability of receiving ATG varied from 7% to 36%. We stratified the analyses according to two periods, from 2013 to 2015 and from 2016 to 2019. A similar heterogeneity was observed, and in some cases ATG indications between the centers were inverted.

Conclusions

The heterogeneity of induction therapy practices did not decrease in France, even if the reated literature is prolific. This illustrates the necessity to improve the literature by using meta-analyses of recent studies stratified by graft and patient profiles.

Modest dose anti-thymocyte globulin administered intraoperatively is safe and effective in kidney transplantations: a retrospective study

BACKGROUND

Anti-thymocyte globulin (ATG) as induction therapy in renal transplantation is facing the dilemma of reducing the incidence of acute rejection (AR) and delayed graft function (DGF) or increasing risks of infection and malignancy. The purpose of this study was to delineate the safety and efficiency of the optimal ATG dosage.

METHODS

We retrospectively evaluated 91 deceased donor kidney transplant recipients (KTRs) in our institution between March 2011 and January 2019. The patients were classified into three groups based on induction therapy: (1) Group 1: modest-dose ATG (three mg/kg) intraoperatively (N = 21); (2) Group 2: low-dose ATG (1-1.5 mg/kg) intraoperatively (N = 23); (3) Group 3: basiliximab 20 mg both on day 0 and 4 (N = 47). In Groups 1 and 2, all patients received a daily low-dose program (1-1.5 mg/kg each day) with target dosage of six mg/kg. Induction therapy was combined with standard immunosuppressive regimen consisting of calcineurin inhibitors, mycophenolate/the mammalian target of rapamycin inhibitors and corticosteroids.

RESULTS

There was no significant difference in patient characteristics among groups. The outcomes of infection rate, biopsy-proven acute rejection, post-transplant diabetes mellitus, graft survival, and patient survival were similar among groups. Compared to the daily low-dose ATG regimen, the intraoperative modest-dose regimen did not cause more dose interruption and hence was more likely to reach the target ATG dosage. The intraoperative modest-dose regimen also seemed to reduce the rate of DGF.

DISCUSSION

In recent years, a trend of using a "lower" dose of ATG has seemed to emerge. Our results suggest intraoperative modest-dose ATG followed by daily low-dose ATG regimen was safe and effective in cadaveric renal transplantations for preventing DGF, AR, and graft loss.

Induction Therapy in Elderly Kidney Transplant Recipients With Low Immunological Risk

BACKGROUND

In nonimmunized patients, similar rejection rates are observed for patients who have undergone thymoglobulin (antithymocyte globulins [ATG]) or basiliximab (BSX) therapy. While ATG may improve delayed graft function, it may also be associated with higher infection rates and malignancy risk. We compared survival and clinical outcomes in elderly recipients with low immunological risk according to their induction therapy.

METHODS

We conducted a multicentric study on nonimmunized patients ≥65 years of age receiving a first kidney transplant between 2010 and 2017. The principal outcome was patient and graft survival. Secondary outcomes were cumulative probabilities of infection, first acute rejection episode, malignancy, de novo donor specific antibody, posttransplant diabetes (PTD), cardiac complications, estimated glomerular filtration rate, and occurrence of delayed graft function. Cox, logistic, or linear statistical models were used depending on the outcome studied, and models were weighted on the propensity scores.

RESULTS

Two hundred and four patients were included in the BSX group and 179 in the ATG group with the average age of 71.0 and 70.5 years, respectively. Patient and graft survival at 3 years posttransplantation were 74% (95% CI, 65%-84%) and 68% (95% CI, 60%-78%) in ATG and BSX group, respectively, without significant difference. Occurrence of PTD was significatively higher in BSX group (23% versus 15%, P = 0.04) due to higher trough levels of Tacrolimus on month 3 (9.48 versus 7.30 ng/mL, P = 0.023). There was no difference in other evaluated outcomes.

CONCLUSIONS

In elderly recipients, ATG does not lead to poorer outcomes compared with BSX and could permit lower trough levels of Tacrolimus, thus reducing occurrence of PTD.

Increased risk of rejection after basiliximab induction in sensitized kidney transplant recipients without pre-existing donor-specific antibodies - a retrospective study

Depleting induction therapy is recommended in sensitized kidney transplant recipients (KTRs), though the detrimental effect of nondonor-specific anti-HLA antibodies is not undeniable. We compared the efficacy and safety of basiliximab and rabbit anti-thymocyte globulin (rATG) in sensitized KTRs without pre-existing donor-specific antibodies (DSAs). This monocentric retrospective study involved all sensitized KTR adults without pre-existing DSAs (n = 218) who underwent transplantation after June 2007. Patients with basiliximab and rATG therapy were compared for risk of biopsy-proven acute rejection (BPAR) and a composite endpoint (BPAR, graft loss and death) by univariate and multivariate analysis. Patients with basiliximab (n = 60) had lower mean calculated panel reactive antibody than those with rATG (n = 158; 23.7 ± 24.2 vs. 63.8 ± 32.3, P < 0.0001) and more often received a first graft (88% vs. 54%, P < 0.0001) and a transplant from a living donor (13% vs. 2%, P = 0.002). Risks of BPAR and of reaching the composite endpoint were greater with basiliximab than rATG [HR = 3.63 (1.70-7.77), P = 0.0009 and HR = 1.60 (0.99-2.59), P = 0.050, respectively]. Several adjustments did not change those risks [BPAR: 3.36 (1.23-9.16), P = 0.018; composite endpoint: 1.83 (0.99-3.39), P = 0.053]. Infections and malignancies were similar in both groups. rATG remains the first-line treatment in sensitized KTR, even in the absence of pre-existing DSAs.

Evaluating safety and efficacy of rabbit antithymocyte globulin induction in elderly kidney transplant recipients

OBJECTIVES

The optimal immunosuppression regimen for elderly kidney transplant recipients is poorly defined. We sought to evaluate the short-term efficacy and safety of thymoglobulin in geriatric recipients of deceased-donor kidneys.

MATERIALS AND METHODS

A single-center, retrospective analysis was undertaken between elderly (≥ 65 years) (n=137) and nonelderly (n=276) kidney transplant recipients who received rabbit antithymocyte globulin induction and calcineurin inhibitor, mycophenolic acid, and prednisone maintenance.

RESULTS

The mean age was 70 versus 52 years. Fewer elderly patients had an earlier transplant or panel reactive antibodies > 20%, but had more machine perfused, older, and extended criteria donor kidneys. Elderly patients received lower rabbit antithymocyte globulin (5.4 vs 5.6 mg/kg; P = .04) and initial mycophenolic acid doses (1620 vs 1774 mg; P = .002), and experienced less delayed graft function (31.1% vs 50.0%; P < .001). Death-censored graft survival and graft function at 3 years and biopsy-proven acute rejection at 1 year were comparable; however, there was lower 3-year patient survival in elderly patients. Donor age was the only factor associated with reduced patient survival. Rates of malignancy, infection, or thrombocytopenia were similar; however, leukopenia occurred less frequently in elderly patients (11.7% vs 19.9%; P = .038).

CONCLUSIONS

Elderly kidney transplant recipients receiving rabbit antithymocyte globulin did not experience different short-term graft survival, graft function or rates of infection, malignancy or hematologic adverse reactions than did nonelderly patients; they experienced fewer episodes of delayed graft function, but had lower 3-year patient survival.

Recurrence and rejection in liver transplantation for primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic progressive inflammatory disease affecting the bile ducts, leading to fibrosis and eventually cirrhosis in most patients. Its etiology is unknown and so far no effective medical therapy is available. Liver transplantation (LTX) is the only curative treatment and at present PSC is the main indication for LTX in the Scandinavian countries. Close to half of the PSC patients experience one or more episodes of acute cellular rejection (ACR) following transplantation and approximately 1/5 of the transplanted patients develop recurrent disease in the graft. In addition, some reports indicate that ACR early after LTX for PSC can influence the risk for recurrent disease. For these important post-transplantation entities affecting PSC patients, we have reviewed the current literature on epidemiology, pathogenesis, treatment and the possible influence of rejection on the risk of recurrent disease in the allograft.

Obesity in renal transplantation: the role of induction therapy on long-term outcomes

Obesity is a burgeoning problem among renal transplant recipients given its association with increased morbidity, graft loss, and mortality. The long-term influence of different induction therapies in obese compared to nonobese patients is uncertain. We examined the long-term effect of low-dose rabbit antithymocyte globulin (rATG; 3-5 mg/kg) induction therapy compared to two doses of 20 mg basiliximab (BSX) in nonobese and obese renal transplant patients. The medical records of all adult (>18 years) recipients of kidney transplants between June 2001 and June 2009 in our center were reviewed. Patients whose body mass index (BMI) was greater than 30 were considered to be obese. The average dose of rATG was 3.2±1.6 mg/kg. A total of 475 patients were included. In the nonobese group with a BMI less than 30, 68 received BSX and 247, rATG. In the obese group, 27 patients were given BSX and 133 were given rATG. Mean follow-up was 1523 days. These four groups were similar in baseline characteristics including: donor and recipient age, percent diabetes, living donors, panel-reactive antibodies>35, HLA mismatch, race, gender, and maintenance immunosuppression. Serum creatinine levels at 3 months and 1, 5, and 7 years were not statistically different between groups. Compared to BSX induction therapy, rATG was associated with better graft survival at 47.4±10 months in obese (63.6% vs 90.3%, P<.05, respectively) as well as nonobese patients (68.2% vs 88.7%, P<.05, respectively). Rejections were numerically lower in rATG-treated obese patients, which reached statistical significance in nonobese patients. Wound and viral infections were not statistically different between rATG and BSX groups. Therefore, low-dose rATG is associated with a better long-term graft survival rate in obese patients without incurring an increased risk of infectious complications. When rATG was used in obese and nonobese patients, there was no difference in graft and patient survival.

Bloodstream infection after kidney transplantation: epidemiology, microbiology, associated risk factors, and outcome

BACKGROUND

Bloodstream infection (BSI) is associated with both relevant morbidity and mortality rates after kidney transplantation.

METHODS

From January 1, 2000 to January 31, 2006, all episodes of BSI were retrospectively assessed through the review of medical records in two tertiary teaching Hospitals in Sao Paulo, Brazil, where 3308 transplant procedures were performed during this period. Contaminants and polymicrobial infections were excluded. The main objectives of the study were to describe clinical and microbiologic aspects of BSI, as well as risk factors for both BSI and mortality from these infections in kidney transplant patients.

RESULTS

BSI was detected in 185 patients, with onset after a median of 235 days after transplantation; 62% occurred after 6 months. The primary source of infection was the urinary tract in 37.8%. The most prevalent pathogen overall was Escherichia coli (30.3%). Risk factors for early acquired BSI (first 6 months after transplantation) were acute rejection, ureteric stent placement, and receiving an organ from a deceased donor. For late BSI (after 6 months), associated risk factors were acute rejection, Charlson Comorbidity Score more than or equal to 3, and receiving an organ from a deceased donor. Risk factors related to 30-day mortality were Acute Physiology and Chronic Health Evaluation II Score more than or equal to 20, shock, and respiratory failure.

CONCLUSIONS

BSI is most frequently a consequence of urinary tract infection, with a high prevalence of gram-negative bacilli. Severity of disease was the main determinant of 30-day mortality after BSI, and based on the knowledge of risk factors, some interventions are suggested for reducing the rate of BSI after transplantation.

Should heart, lung, and liver transplant recipients receive immunosuppression induction for kidney transplantation?

As the outcomes of heart, liver, and lung transplantation continue to improve, more patients will present for subsequent renal transplantation. It remains unclear whether these patients benefit from induction immunosuppression. We retrospectively reviewed induction on solid organ graft recipients who underwent renal transplant at our center from January 1, 1995 to March 30, 2007. Induction and the non-induction groups were compared by univariate and Kaplan-Meier analyses. There were 21 patients in each group, with mean follow-up of 4.5-6.0 years. Forty-seven percent of patients receiving induction had a severe post-operative infection, compared with 28.6% in the non-induction group (p = NS). The one yr rejection rate in the induction group was 9.5% compared with 14.3% for non-induction (p = NS). One-yr graft survival was 81.0% and 95.2% in the induction and non-induction group (p = NS). In summary, there is a trend toward lower patient and graft survival among patients undergoing induction. These trends could relate to selection bias in the decision to prescribe induction immunosuppression, but further study is needed to better define the risks and benefits of antibody-induction regimens in this population.

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.