Immunosuppressive Drugs After Simultaneous Pancreas-Kidney Transplantation

Outcome-Orientated Organ Allocation-A Composite Risk Model for Pancreas Graft Evaluation and Acceptance

Background: Pancreas transplantation (PTX) remains the most effective treatment to prevent long-term complications and provide consistent euglycemia in patients with endocrine pancreatic insufficiency, mainly in type I diabetic patients. Considering early graft loss (EGL) and the perioperative complication rate, an optimal risk stratification based on donor risk factors is paramount. Methods: In our single-center study, we retrospectively assessed the risk factors for EGL and reduced graft survival in 97 PTXs (82 simultaneous pancreas and kidney [SPK], 11 pancreases transplanted after kidney [PAK] and 4 pancreases transplanted alone [PTA]) between 2010 and 2021. By statistically analyzing the incorporation of different donor risk factors using the Kaplan-Meier method and a log-rank test, we introduced a composite risk model for the evaluation of offered pancreas grafts. Results: The overall EGL rate was 6.5%. In the univariate analysis of donor characteristics, age > 45 years, BMI > 25 kg/m2, lipase > 60 U/L, cerebrovascular accident (CVA) as the cause of death, mechanical cardiopulmonary resuscitation (mCPR), cold ischemia time (CIT) > 600 min and retrieval by another center were identified as potential risk factors; however, they lacked statistical significance. In a multivariate model, age > 45 years (HR 2.05, p = 0.355), BMI > 25 kg/m2 (HR 3.18, p = 0.051), lipase > 60 U/L (HR 2.32, p = 0.148), mCPR (HR 8.62, p < 0.0001) and CIT > 600 min (HR 1.89, p = 0.142) had the greatest impact on pancreas graft survival. We subsumed these factors in a composite risk model. The combination of three risk factors increased the rate of EGL significantly (p = 0.003). Comparing the pancreas graft survival curves for ≥3 risk factors to <3 risk factors in a Kaplan-Meier model revealed significant inferiority in the pancreas graft survival rate (p = 0.029). Conclusions: When evaluating a potential donor organ, grafts with a combination of three or more risk factors should only be accepted after careful consideration to reduce the risk of EGL and to significantly improve outcomes after PTX.

ATG-Fresenius increases the risk of red blood cell transfusion after kidney transplantation

Introduction

In sensitized deceased donor kidney allograft recipients, the most frequent induction therapy is anti-thymocyte globulins (ATG), including Thymoglobulin® (Thymo) and ATG-Fresenius (ATG-F).

Methods

We conducted a 3-year monocentric observational study to compare the impact of ATGs on hematological parameters. We included adult kidney transplant recipients treated with ATG induction therapy, either Thymo or ATG-F, on a one-in-two basis. The primary endpoint was red blood cell (RBC) transfusions within 14 days after transplantation.

Results

Among 309 kidney allograft recipients, 177 (57.2%) received ATG induction, 90 (50.8 %) ATG-F, and 87 (49.2%) Thymo. The ATG-F group received significantly more RBC transfusions (63.3% vs. 46% p = 0.02) and in bigger volumes (p = 0.01). Platelet transfusion was similar in both groups. Within 14 and 30 days after transplantation, older age, ATG-F induction, and early surgical complication were independently associated with RBC transfusion. Patient survival rate was 95%, and the death-censored kidney allograft survival rate was 91.5% at 12 months post-transplantation. There was no difference in the incidence of acute rejection and infections or in the prevalence of anti-HLA donor-specific antibodies.

Discussion

In conclusion, after kidney transplantation, ATG-F is an independent risk factor for early RBC transfusion and early thrombocytopenia without clinical and biological consequences. These new data should be clinically considered, and alternatives to ATG should be further explored.

A Comparison of Two Types of Rabbit Antithymocyte Globulin Induction Therapy in Immunological High-Risk Kidney Recipients: A Prospective Randomized Control Study

Background

Induction treatment with rabbit polyclonal antithymocyte globulins (ATGs) is frequent used in kidney transplant recipients with donorspecific HLA antibodies and shows acceptable outcomes. The two commonly used ATGs, Thymoglobulin and ATG-F have slightly different antigen profile and antibody concentrations. The two compounds have never been directly compared in a prospective trial in immunological high-risk recipients. Therefore we performed a prospective randomized controlled study comparing the two compounds in immunological high-risk kidney recipients in terms of safety and efficacy.

Methods

Immunological high-risk kidney recipients, defined as the presence of HLA DSA but negative CDC-B and T-cell crossmatches were randomized 1:1 to receive ATG-F or Thymoglobulin. Maintenance immunosuppressive therapy consisted of tacrolimus, mycophenolate mofetil and steroids.

Results

The per-protocol analysis included 35 patients. There was no immediate infusion reaction observed with both compounds. No PTLD or malignancy occurred during the follow-up in both groups. The incidence of viral and bacterial infections was similar in both groups (p = 0.62). The cumulative incidence of clinical and subclinical antibody mediated allograft rejection as well as T-cell mediated allograft rejection during the first year between ATG-F and Thymoglobulin was similar (35% versus 19%; p = 0.30 and 11% versus 18%; 0.54 respectively). The two-year graft function was similar with a median eGFR of 56 ml/min/1.73m² (range 21–128) (ATG-F-group) and 51 ml/min/1.73m² (range 22–132) (Thymo-group) (p = 0.69).

Conclusion

We found no significant differences between the compared study drugs for induction treatment in immunological high-risk patients regarding safety and efficacy during follow-up with good allograft function at 2 years after transplantation.

Charcot neuroarthropathy after simultaneous pancreas-kidney transplantation: risk factors, prevalence, and outcome

We retrospectively analyzed outcome and risk factors of developing Charcot foot (CF) in 100 patients with type 1 diabetes mellitus who underwent a simultaneous pancreas-kidney (SPK) transplantation. Patients who developed CF after SPK transplantation had significantly higher mortality (56% vs. 18%) and more frequently graft failure (44% vs. 13%). Recipients with CF also experienced acute rejections more frequently (78% vs. 41%). They furthermore had higher pre-transplant values of HbA1c , received cyclosporine and azathioprine more often, and had significantly higher cumulative corticosteroid use. Patients transplanted in an earlier era (1992-1998) received cyclosporine and azathioprine more often and had a significantly higher cumulative corticosteroid use with the higher prevalence of CF. Conversely, patients with diabetes transplanted more recently (1999-2012) received lower doses of corticosteroids as part of their tacrolimus-based immunosuppressive therapy, resulting in fewer CF attacks. In conclusion, development of CF after SPK is associated with poor patient and graft outcome. Poor pre-transplant diabetic control and the use of high-dose corticosteroids are risk factors for the development of CF. We recommend reduction in or even total avoidance of corticosteroids after SPK transplantation. Given the importance of the diagnosis of CF on outcome, a systematic examination of SPK patients' feet is recommended.

Steroid avoidance or withdrawal for pancreas and pancreas with kidney transplant recipients

BACKGROUND

Pancreas or kidney-pancreas transplantation improves survival and quality of life for people with type 1 diabetes mellitus and kidney failure. Immunosuppression after transplantation is associated with complications. Steroids have adverse effects on cardiovascular risk factors such as hypertension, hyperglycaemia or hyperlipidaemia, increase risk of infection, obesity, cataracts, myopathy, bone metabolism alterations, dermatologic problems and cushingoid appearance. Whether avoiding steroids changes outcomes is unclear.

OBJECTIVES

We aimed to assess the safety and efficacy of steroid early withdrawal (treatment for less than 14 days after transplantation), late withdrawal (after 14 days after transplantation) or steroid avoidance in patients receiving a pancreas (including a vascularized organ) alone (PTA), simultaneous with a kidney (SPK) or after kidney transplantation (PAK).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register (to 18 June 2014) through contact with the Trials' Search Co-ordinator. We handsearched: reference lists of nephrology textbooks, relevant studies, recent publications and clinical practice guidelines; abstracts from international transplantation society scientific meetings; and sent emails and letters seeking information about unpublished or incomplete studies to known investigators.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or cohort studies of steroid avoidance (including early withdrawal) versus steroid maintenance or versus late withdrawal in pancreas or pancreas with kidney transplant recipients. We defined steroid avoidance as complete avoidance of steroid immunosuppression, early steroid withdrawal as steroid treatment for less than 14 days after transplantation and late withdrawal as steroid withdrawal after 14 days after transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the retrieved titles and abstracts, and where necessary the full text reports to determine which studies satisfied the inclusion criteria. Authors of included studies were contacted to obtain missing information. Statistical analyses were performed using random effects models and results expressed as risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Cohort studies were not meta-analysed, but their findings summarised descriptively.

MAIN RESULTS

Three RCTs enrolling 144 participants met our inclusion criteria. Two compared steroid avoidance versus late steroid withdrawal and one compared late steroid withdrawal versus steroid maintenance. All studies included SPK and only one also included PTA. All studies had an overall moderate risk of bias and presented only short-term results (six to 12 months). Two studies (89 participants) compared steroid avoidance or early steroid withdrawal versus late steroid withdrawal. There was no clear evidence of an impact on mortality (2 studies, 89 participants: RR 1.64, 95% CI 0.21 to 12.75), risk of kidney loss censored for death (2 studies, 89 participants: RR 0.35, 95% CI 0.04 to 3.09), risk of pancreas loss censored for death (2 studies, 89 participants: RR 1.05, 95% CI 0.36 to 3.04), or acute kidney rejection (1 study, 49 participants: RR 2.08, 95% CI 0.20 to 21.50), however results were uncertain and consistent with no difference or important benefit or harm of steroid avoidance/early steroid withdrawal. The study that compared late steroid withdrawal versus steroid maintenance observed no deaths, no graft loss or acute kidney rejection at six months in either group and reported uncertain effects on acute pancreas rejection (RR 0.88, 95% CI 0.06 to 13.35). Of the possible adverse effects only infection was reported by one study. There were significantly more UTIs reported in the late withdrawal group compared to the steroid avoidance group (1 study, 25 patients: RR 0.41, 95% CI 0.26 to 0.66).We also identified 13 cohort studies and one RCT which randomised tacrolimus versus cyclosporin. These studies in general showed that steroid-sparing and withdrawal strategies had benefits in lowering HbAc1 and risk of infections (BK virus and CMV disease) and improved blood pressure control without increasing the risk of rejection. However, two studies found an increased incidence of acute pancreas rejection (HR 2.8, 95% CI 0.89 to 8.81, P = 0.066 in one study and 43.3% in the steroid withdrawal group versus 9.3% in the steroid maintenance, P < 0.05 at three years in the other) and one study found an increased incidence of acute kidney rejection (18.7% in the steroid withdrawal group versus 2.8% in the steroid maintenance, P < 0.05) at three years.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence for the benefits and harms of steroid withdrawal in pancreas transplantation in the three RCTs (144 patients) identified. The results showed uncertain results for short-term risk of rejection, mortality, or graft survival in steroid-sparing strategies in a very small number of patients over a short period of follow-up. Overall the data was sparse, so no firm conclusions are possible. Moreover, the 13 observational studies findings generally concur with the evidence found in the RCTs.

A review on comparing two commonly used rabbit anti-thymocyte globulins as induction therapy in solid organ transplantation

INTRODUCTION

Two rabbit anti-thymocyte globulins (ATGs) (Thymoglobulin™ and ATG-Fresenius (ATG-F)™) have been used commonly for induction immunosuppression and treatment of acute rejection in solid organ transplantation. Therefore, literature review on comparative efficacy and side-effect profile of them would be of clinical interest.

AREAS COVERED

This review evaluated all comparative studies in English language, focusing on the solid organ transplant patients who received Thymoglobulin or ATG-F as induction therapy. This review concluded that compared to ATG-F, Thymoglobulin possibly provides better protection against acute rejection and improves patient and graft survival but may result in more cytomegalovirus infection and post-transplant malignancy. Thymoglobulin produced more leukocyte depletion with a greater delay to recover, while ATG-F had more reduction effects on platelet and erythrocyte counts with an increased need to erythropoiesis-stimulating agent.

EXPERT OPINION

The benefits of induction therapy with ATGs must be weighed against the costs and post-transplant complications. It is suggest that there is no substantial clinical difference between these two rabbit ATGs and each may be considered as induction therapy for solid organ transplantation based on availability and drug cost. Of special importance is adding antiviral therapy to the treatment regimen of patients who receive ATGs as induction therapy.

Altered balance between effector T cells and FOXP3+ HELIOS+ regulatory T cells after thymoglobulin induction in kidney transplant recipients

This study examined the effect of thymoglobulin induction therapy on leukocyte population dynamics in kidney transplant patients. Patients receiving standard immunosuppression were compared with those who received additional thymoglobulin at the time of kidney transplantation. Thymoglobulin induction led to an immediate and significant decrease of all T cells and NK cells, but not B cells or monocytes. CD8(+) T cells recovered to near pretransplant level by 4 weeks post-transplant. CD4(+) T cells remained at less than 30% of pretransplant level for the entire study period of 78 weeks. Both CD4(+) and CD8(+) T cells showed reduced cytokine production after recovery. Deletion of CD4(+) FOXP3(+) HELIOS(+) regulatory T cells (Tregs) was less profound than that of CD4(+) FOXP3(-) cells, thus the relative percentage of Tregs elevated significantly when compared with pretransplant levels in thymoglobulin-treated patients. In contrast, the percentages of Tregs and their expression of FOXP3 in the standard immunosuppression group decreased steadily and by 12 weeks after transplant the average percentage of Tregs was 56% of the pretransplant level. Thus, thymoglobulin-induced deletion of T cells led to significant and long-lasting alterations of the T-cell compartment characterized by a preservation of Tregs and long-lasting reduction in CD4(+) , and potentially pathogenic, T cells.