Harnessing Immune Cell Metabolism to Modulate Alloresponse in Transplantation

Immune cell metabolism plays a pivotal role in shaping and modulating immune responses. The metabolic state of immune cells influences their development, activation, differentiation, and overall function, impacting both innate and adaptive immunity. While glycolysis is crucial for activation and effector function of CD8 T cells, regulatory T cells mainly use oxidative phosphorylation and fatty acid oxidation, highlighting how different metabolic programs shape immune cells. Modification of cell metabolism may provide new therapeutic approaches to prevent rejection and avoid immunosuppressive toxicities. In particular, the distinct metabolic patterns of effector and suppressive cell subsets offer promising opportunities to target metabolic pathways that influence immune responses and graft outcomes. Herein, we review the main metabolic pathways used by immune cells, the techniques available to assay immune metabolism, and evidence supporting the possibility of shifting the immune response towards a tolerogenic profile by modifying energetic metabolism.

Legionnaires Disease in Solid Organ Transplant Recipients: A Decade-Long Nationwide Study in France

BACKGROUND

Legionnaires disease (LD) is a rare, life-threatening opportunistic bacterial infection that poses a significant risk to patients with impaired cell-mediated immunity such as solid organ transplant recipients. However, the epidemiologic features, clinical presentation, and outcomes of LD in this population are poorly described.

RESEARCH QUESTION

What are the clinical manifestations, radiologic presentation, risk factors for severity, treatment, and outcome of LD in solid organ transplant recipients?

STUDY DESIGN AND METHODS

In this 10-year multicenter retrospective cohort study in France, where LD notification is mandatory, patients were identified by hospital discharge databases. Diagnosis of LD relied on positive culture findings from any respiratory sample, positive urinary antigen test (UAT) results, positive specific serologic findings, or a combination thereof. Severe LD was defined as admission to the ICU.

RESULTS

One hundred one patients from 51 transplantation centers were eligible; 64 patients (63.4%) were kidney transplant recipients. Median time between transplantation and LD was 5.6 years (interquartile range, 1.5-12 years). UAT results were positive in 92% of patients (89/97). Among 31 patients with positive culture findings in respiratory samples, Legionella pneumophila serogroup 1 was identified in 90%. Chest CT imaging showed alveolar consolidation in 98% of patients (54 of 57), ground-glass opacity in 63% of patients (36 of 57), macronodules in 21% of patients (12 of 57), and cavitation in 8.8% of patients (5 of 57). Fifty-seven patients (56%) were hospitalized in the ICU. In multivariate analysis, severe LD was associated with negative UAT findings at presentation (P = .047), lymphopenia (P = .014), respiratory symptoms (P = .010), and pleural effusion (P = .039). The 30-day and 12-month mortality rates were 8% (8 of 101) and 20% (19 of 97), respectively. In multivariate analysis, diabetes mellitus was the only factor associated with 12-month mortality (hazard ratio, 3.2; 95% OR, 1.19-8.64; P = .022).

INTERPRETATION

LD is a late and severe complication occurring in solid organ transplant recipients that may present as pulmonary nodules on which diabetes impacts its long-term prognosis.

Recurrence of membranous nephropathy after kidney transplantation: A multicenter retrospective cohort study

Membranous nephropathy (MN) is a leading cause of kidney failure worldwide and frequently recurs after transplant. Available data originated from small retrospective cohort studies or registry analyses; therefore, uncertainties remain on risk factors for MN recurrence and response to therapy. Within the Post-Transplant Glomerular Disease Consortium, we conducted a retrospective multicenter cohort study examining the MN recurrence rate, risk factors, and response to treatment. This study screened 22,921 patients across 3 continents and included 194 patients who underwent a kidney transplant due to biopsy-proven MN. The cumulative incidence of MN recurrence was 31% at 10 years posttransplant. Patients with a faster progression toward end-stage kidney disease were at higher risk of developing recurrent MN (hazard ratio [HR], 0.55 per decade; 95% confidence interval [CI], 0.35-0.88). Moreover, elevated pretransplant levels of anti-phospholipase A2 receptor (PLA2R) antibodies were strongly associated with recurrence (HR, 18.58; 95% CI, 5.37-64.27). Patients receiving rituximab for MN recurrence had a higher likelihood of achieving remission than patients receiving renin-angiotensin-aldosterone system inhibition alone. In sum, MN recurs in one-third of patients posttransplant, and measurement of serum anti-PLA2R antibody levels shortly before transplant could aid in risk-stratifying patients for MN recurrence. Moreover, patients receiving rituximab had a higher rate of treatment response.

Adverse Drug Events after Kidney Transplantation

Introduction: Kidney transplantation stands out as the optimal treatment for patients with end-stage kidney disease, provided they meet specific criteria for a secure outcome. With the exception of identical twin donor-recipient pairs, lifelong immunosuppression becomes imperative. Unfortunately, immunosuppressant drugs, particularly calcineurin inhibitors like tacrolimus, bring about adverse effects, including nephrotoxicity, diabetes mellitus, hypertension, infections, malignancy, leukopenia, anemia, thrombocytopenia, mouth ulcers, dyslipidemia, and wound complications. Since achieving tolerance is not feasible, patients are compelled to adhere to lifelong immunosuppressive therapies, often involving calcineurin inhibitors, alongside mycophenolic acid or mTOR inhibitors, with or without steroids. Area covered: Notably, these drugs, especially calcineurin inhibitors, possess narrow therapeutic windows, resulting in numerous drug-related side effects. This review focuses on the prevalent immunosuppressive drug-related side effects encountered in kidney transplant recipients, namely nephrotoxicity, post-transplant diabetes mellitus, leukopenia, anemia, dyslipidemia, mouth ulcers, hypertension, and viral reactivations (cytomegalovirus and BK virus). Additionally, other post-kidney-transplantation drugs such as valganciclovir may also contribute to adverse events such as leukopenia. For each side effect, we propose preventive measures and outline appropriate treatment strategies.

Imlifidase for Kidney Transplantation of Highly Sensitized Patients With a Positive Crossmatch: The French Consensus Guidelines

Imlifidase recently received early access authorization for highly sensitized adult kidney transplant candidates with a positive crossmatch against an ABO-compatible deceased donor. These French consensus guidelines have been generated by an expert working group, in order to homogenize patient selection, associated treatments and follow-up. This initiative is part of an international effort to analyze properly the benefits and tolerance of this new costly treatment in real-life. Eligible patients must meet the following screening criteria: cPRA ≥ 98%, ≤ 65-year of age, ≥ 3 years on the waiting list, and a low risk of biopsy-related complications. The final decision to use Imlifidase will be based on the two following criteria. First, the results of a virtual crossmatch on recent serum, which shall show a MFI for the immunodominant donor-specific antibodies (DSA) > 6,000 but the value of which does not exceed 5,000 after 1:10 dilution. Second, the post-Imlifidase complement-dependent cytotoxicity crossmatch must be negative. Patients treated with Imlifidase will receive an immunosuppressive regimen based on steroids, rATG, high dose IVIg, rituximab, tacrolimus and mycophenolic acid. Frequent post-transplant testing for DSA and systematic surveillance kidney biopsies are highly recommended to monitor post-transplant DSA rebound and subclinical rejection.

A multicentre, patient- and assessor-blinded, non-inferiority, randomised and controlled phase II trial to compare standard and torque teno virus-guided immunosuppression in kidney transplant recipients in the first year after transplantation: TTVguideIT

BACKGROUND

Immunosuppression after kidney transplantation is mainly guided via plasma tacrolimus trough level, which cannot sufficiently predict allograft rejection and infection. The plasma load of the non-pathogenic and highly prevalent torque teno virus (TTV) is associated with the immunosuppression of its host. Non-interventional studies suggest the use of TTV load to predict allograft rejection and infection. The primary objective of the current trial is to demonstrate the safety, tolerability and preliminary efficacy of TTV-guided immunosuppression.

METHODS

For this purpose, a randomised, controlled, interventional, two-arm, non-inferiority, patient- and assessor-blinded, investigator-driven phase II trial was designed. A total of 260 stable, low-immunological-risk adult recipients of a kidney graft with tacrolimus-based immunosuppression and TTV infection after month 3 post-transplantation will be recruited in 13 academic centres in six European countries. Subjects will be randomised in a 1:1 ratio (allocation concealment) to receive tacrolimus either guided by TTV load or according to the local centre standard for 9 months. The primary composite endpoint includes the occurrence of infections, biopsy-proven allograft rejection, graft loss, or death. The main secondary endpoints include estimated glomerular filtration rate, graft rejection detected by protocol biopsy at month 12 post-transplantation (including molecular microscopy), development of de novo donor-specific antibodies, health-related quality of life, and drug adherence. In parallel, a comprehensive biobank will be established including plasma, serum, urine and whole blood. The date of the first enrolment was August 2022 and the planned end is April 2025.

DISCUSSION

The assessment of individual kidney transplant recipient immune function might enable clinicians to personalise immunosuppression, thereby reducing infection and rejection. Moreover, the trial might act as a proof of principle for TTV-guided immunosuppression and thus pave the way for broader clinical applications, including as guidance for immune modulators or disease-modifying agents.

TRIAL REGISTRATION

EU CT-Number: 2022-500024-30-00.

Quantification of belatacept by liquid chromatography-tandem mass spectrometry in human plasma: Application to a pharmacokinetic study in renal transplant recipients

Therapeutic drug monitoring is the cornerstone of immunosuppressive treatment in transplantation. The immunosuppressive drugs used in kidney transplant patients are mostly comprised of biologics, including therapeutic monoclonal antibodies (mAbs) and fusion proteins. Therefore, a specific and sensitive analytical technique that can universally quantify mAbs, as well as fusion proteins, is essential for clinical pharmacokinetics studies. In this short communication, we describe the validation of a liquid chromatography tandem mass-spectrometry (LC-MS/MS) method for quantification of the fusion protein belatacept in the plasma of kidney-transplant patients. Sample preparation was based on our previously published and implementable electrospray ionization LC-MS/MS method that allows the simultaneous quantification of seven mAbs. Immunocapture was made possible by the Fc domain of belatacept and identification/quantification by the choice of MRM transitions of peptides. The temporal evolution of the belatacept concentration after intravenous infusion and inter-individual variability of trough concentrations were assessed in 17 human plasma samples. The belatacept calibration curves were linear from 1 to 200 mg.L^-1 and within-day and between-day accuracy and precision fulfilled Food and Drug Administration validation criteria. Residual belatacept concentrations (n = 8) ranged from 5.1 to 15.0 mg.L^-1, with a median of 8.9 mg.L^-1 and an inter-individual CV of 33.0%. Our generic LC-MS/MS method allows the quantification of fusion proteins, such as belatacept, and could be used for therapeutic drug monitoring. This method provides a useful tool to study the intra-patient variability of belatacept and the association between belatacept exposure and its therapeutic effects.

Cryoglobulinemia and double-filtration plasmapheresis: Personal experience and literature review

BACKGROUND

Cryoglobulinemia is defined as the presence of an abnormal immunoglobulin that may be responsible for vasculitis of small-caliber vessels. Apheresis can be used in order to temporarily eliminate circulating cryoglobulins. The aim of this study was to assess the effectiveness of apheresis (double-filtration plasmapheresis-DFPP-) in symptomatic and/or severe cryoglobulinemias.

METHODS

Four male patients presenting cryoglobulinemic vasculitis and who received DFPP sessions were included.

RESULTS

Their mean age was 57 ± 15 years. One patient had hepatitis-C virus (HCV)-related cryoglobulinemia and the other three patients were carriers of an IgM Kappa monoclonal gammopathy. Mean duration of follow-up was 15 ± 2 months. DFPP allowed healing of ulcerative skin lesions in the first patient and remission of nephrotic syndrome in the other patients after a median of 6(5-10) sessions.

CONCLUSION

DFPP can be used safely in cryoglobulinemic-vasculitis and can be considered early to achieve a faster and sustained clinical-biological response.

Imlifidase therapy: exploring its clinical uses

INTRODUCTION

Imlifidase, the IgG-degrading enzyme derived from Streptococcus pyogenes, can cleave all four human IgG subclasses with precise specificity. All IgG molecules can be inactivated for ~1-to-2 weeks, until new IgG synthesis is detected.

AREAS COVERED

Imlifidase was first studied for the desensitization of highly HLA-sensitized patients to enable kidney transplantation. It is currently being evaluated for kidney transplant recipients who have antibody-mediated rejection (AMR), those with acute kidney injury in the setting of anti-glomerular basement membrane disease, and those with Guillain-Barré syndrome. In 2020, imlifidase received conditional approval from the European Medicines Agency for use to desensitize deceased-donor kidney transplant recipients with a positive crossmatch. Literature search through PubMed revealed that so far, 39 crossmatched-positive patients, i.e. in the presence of donor-specific alloantibodies (DSA) on the transplantation day, have received imlifidase prior to kidney transplantation in four single-arm, open-label, phase II studies. Results at 3-year follow-up are good, i.e. allograft survival is 84%, despite 38% of patients presenting with acute AMR. Mean estimated glomerular filtration rate at 3 years was 55 mL/min/1.73 m².

EXPERT OPINION

The major hurdle now is how to prevent/avoid DSA rebound within days 5-15 post-transplantation. Thus, imlifidase represents a major breakthrough for highly HLA-sensitized kidney transplant candidates, particularly those that have calculated panel-reactive alloantibodies of ≥90%.

Tocilizumab Evaluation in HLA-Desensitization before Kidney Transplantation as an Add-On Therapy to Apheresis: The TETRA Study

BACKGROUND

Desensitization strategies improve access to transplantation in highly sensitized kidney transplant candidates. Tocilizumab could be a valuable addition to more traditional desensitization regimens. We investigated the effect of tocilizumab as an add-on therapy to our standard of care (SoC) desensitization strategy based on rituximab and apheresis.

METHODS

In this study, we prospectively included highly sensitized patients to receive monthly tocilizumab infusions for 6 months before our SoC regimen (Toci + SoC group). We compared the reductions in the mean fluorescent intensity (MFI) rebound at post-transplantation and kidney function at 1-year post-transplantation to patients treated by SoC (based on apheresis and two doses of rituximab).

RESULTS

Twenty-six patients were included in the SoC group; seven in the Toci + SoC group. Reductions in pre-transplantation MFI were similar between groups. At 1-year post-transplantation, there was no absolute difference in overall MFI rebounds, including donor-specific antibodies. Toci + SoC helped lower the rebound of antibodies with more elevated baseline MFIs. Graft function and survival rates were similar at one-year post-transplantation (median eGFR 62.8 vs. 65.6 mL/min/1.73 m² for SoC and Toci + SoC, respectively).

CONCLUSIONS

Tocilizumab as an add-on to SoC desensitization may help control the post-transplantation rebound of antibodies with elevated baseline MFIs. However, reductions in pre-transplantation MFIs were similar with or without tocilizumab. Further studies are needed to validate this pilot study.

Management and Outcome After Early Renal Transplant Vein Thrombosis: A French Multicentre Observational Study of Real-Life Practice Over 24 Years

Early (<14 days) renal transplant vein thrombosis posttransplant (eRVTPT) is a rare but threatening complication. We aimed to assess eRVTPT management and the rate of functional renal transplantation. Of 11,172 adult patients who had undergone transplantation between 01/1997 and 12/2020 at 6 French centres, we identified 176 patients with eRVTPT (1.6%): 16 intraoperative (Group 1, G1) and 160 postoperative (Group 2, G2). All but one patient received surgical management. Patients in group G2 had at least one imaging test for diagnostic confirmation (N = 157, 98%). During the operative management of the G2 group, transplantectomy for graft necrosis was performed immediately in 59.1% of cases. In both groups, either of two techniques was preferred, namely, thrombectomy by renal venotomy or thrombectomy + venous anastomosis repair, with no difference in the functional graft rate (FGR) at hospital discharge (p = NS). The FGR was 62.5% in G1 and 8.1% in G2 (p < 0.001). Numerous complications occurred during the initial hospitalization: 38 patients had a postoperative infection (21.6%), 5 experienced haemorrhagic shock (2.8%), 29 exhibited a haematoma (16.5%), and 97 (55.1%) received a blood transfusion. Five patients died (2.8%). Our study confirms the very poor prognosis of early renal graft venous thrombosis.

[Improving access to kidney transplantation for highly sensitized patients: What place for IL-6 pathway blockade in desensitization protocols?]

BACKGROUND

Desensitization allows kidney transplantation for HLA highly sensitized subjects. Due to the central role of IL-6 in immunological response, tocilizumab (monoclonal antibody directed against IL-6 receptor) could probably improve desensitization efficacy.

METHODS

Pubmed systematic review by using MeSH terms: tocilizumab, clazakizumab, interleukin-6 blockade, kidney transplantation, kidney graft and desensitization.

STUDIES

IL-6 plays a role in humoral response (plasmocyte differentiation induced by lymphocyte T, IL-21 secretion) as well as in cellular response (differentiation of LT Th17 rather than T reg). In desensitization field, tocilizumab was first studied as second-line treatment after failing of standard-of-care (apheresis, rituximab ± IgIV). Recent study showed that tocilizumab as a monotherapy attenuated anti-HLA antibodies rates but was not sufficient to allow transplantation. However, lymphocyte immunophenotyping showed that tocilizumab hindered B cells maturation. Thereby, tocilizumab could improve long-term efficacy of desensitization, by limiting the anti-HLA rebound and so avoiding antibody-mediated rejection. This hypothesis is supported by a recent study which used clazakizumab (monoclonal antibody directed against IL-6) in association with standard-of-care. In that study, clazakizumab was continued after kidney transplantation. Results were encouraging because 9/10 patients were transplanted and there was no donor-specific antibody at 6 months post-transplantation.

CONCLUSION

IL-6 pathway blockade as a monotherapy fails to desensitize HLA highly sensitized kidney transplant candidates. In association with standard-of-care, it does not seem to significatively improve kidney allograft access (short-term efficacy) vs. standard-of-care only. However, it could improve long-term prognosis of HLA incompatible transplantation by orienting the response towards a tolerogenic profile, by hindering B-cell maturation and, thereby, avoiding DSA rebounds after transplantation. This hypothesis needs to be proven by further studies.

Emerging strategies for antibody-mediated rejection

PURPOSE OF THE REVIEW

Antibody-mediated rejection (AMR) is the leading cause of kidney graft loss. Very few treatment options are available to the clinician to counter this disease process. In this review we describe the available therapeutics and the novel approaches that are being currently developed.

RECENT FINDINGS

AMR treatment requires a multidrug approach. Imlifidase, a new immunoglobulin G cleaving agent, may prove to be the perfect replacement of apheresis. New complement blockers other than eculizumab are in development in order to block acute kidney damage in the delicate phase following antibody removal. Plasma cell depletion is being explored in chronic AMR: studies are in progress with daratumumab and felzartamab. Interleukin 6 inhibition is generating enthusiasm in the chronic setting with preliminary encouraging results.

SUMMARY

In acute AMR, the clinicians will have to remove the antibodies, avoid rebound and block specific damage effectors. In chronic AMR they will need to reduce the inflammatory response induced by donor specific antibodies. New drugs are available and transplant physicians are starting to develop effective multidrug strategies to counter the complex disease mechanisms. Safety of these drugs needs to be further explored especially when used together with other potent immunosuppressive drugs.

Absence of Mortality Differences Between the First and Second COVID-19 Waves in Kidney Transplant Recipients

Introduction

SARS-CoV-2 pandemic evolved in 2 consecutive waves during 2020. Improvements in the management of COVID-19 led to a reduction in mortality rates among hospitalized patients during the second wave. Whether this progress benefited kidney transplant recipients (KTRs), a population particularly vulnerable to severe COVID-19, remained unclear.

Methods

In France, 957 KTRs were hospitalized for COVID-19 in 2020 and their data were prospectively collected into the French Solid Organ Transplant (SOT) COVID registry. The presentation, management, and outcomes of the 359 KTRs diagnosed during the first wave were compared to those of the 598 of the second wave.

Results

Baseline comorbidities were similar between KTRs of the 2 waves. Maintenance immunosuppression was reduced in most patients but withdrawal of antimetabolite (73.7% vs. 58.4%, P < 0.001) or calcineurin inhibitor (32.1% vs. 16.6%, P < 0.001) was less frequent during the second wave. Hydroxychloroquine and azithromycin that were commonly used during the first wave (21.7% and 30.9%, respectively) but were almost abandoned during the second wave. In contrast, the use of high dose corticosteroids doubled (19.5% vs. 41.6%, P < 0.001). Despite these changing trends in COVID-19 management, 60-day mortality was not statistically different between the 2 waves (25.3% vs. 23.9%; Log Rank, P = 0.48) and COVID-19 hospitalization period was not associated with death due to COVID-19 in multivariate analysis (Hazard ratio 0.89, 95% confidence interval 0.67–1.17, P = 0.4).

Conclusion

We conclude that changing of therapeutic trends during 2020 did not reduce COVID-19 related mortality among KTRs. Our data indirectly support the importance of vaccination and neutralizing monoclonal anti-SARS-CoV-2 antibodies to protect KTRS from severe COVID-19.

MO1001: Tocilizumab in the Treatment of Chronic Antibody-Mediated Rejection Post Kidney Transplantation: Clinical and Histological Monitoring

BACKGROUND AND AIMS

Chronic antibody-mediated rejection (cAMR) has very few effective therapeutic options. Interleukin-6 is an attractive target because it is involved in inflammation and humoral immunity. Therefore, the use of tocilizumab (anti-IL6 receptor, TCZ) is a potential valuable therapeutic option to treat cABMR in kidney-transplant (KT) recipients

METHOD

This single-centre retrospective study included all KT recipients that received monthly TCZ infusions in the setting of cABMR, between August 2018 and July 2021. We assessed 12-month renal function and KT histology during follow-up.

RESULTS

Forty patients were included. At 12-months, eGFR was not significantly different, 41.6 ± 17 versus 43 ± 17 mL/min/1.73 m2 (P = .102) in patients with functional graft. Six patients (15%) lost their grafts: Their condition was clinically more severe at the time of the first TCZ infusion. Histological follow-up showed no statistical difference in the scores of glomerulitis, peritubular capillaritis, and interstitial fibrosis/tubular atrophy (IFTA). However, the chronic glomerulopathy score, increased significantly over time, and conversely, arteritis and inflammation in IFTA ares improved in follow-up biopsies.

CONCLUSION

In our study, the addition of TCZ prevented clinical and histological worsening of cABMR in KT recipients, except for more severely ill patients. Randomized studies are needed to clarify the risk/benefit of TCZ in cABMR.

Tocilizumab and Active Antibody-Mediated Rejection in Kidney Transplantation: A Literature Review

Introduction

Chronic kidney disease (CKD) is a major public-health problem that increases the risk of end-stage kidney disease (ESKD), cardiovascular diseases, and other complications. Kidney transplantation is a renal-replacement therapy that offers better survival compared to dialysis. Antibody-mediated rejection (ABMR) is a significant complication following kidney transplantation: it contributes to both short- and long-term injury. The standard-of-care (SOC) therapy combines plasmapheresis and Intravenous Immunoglobulins (IVIg) with or without steroids, with or without rituximab: however, despite this combined treatment, ABMR remains the main cause of graft loss. IL-6 is a key cytokine: it regulates inflammation, and the development, maturation, and activation of T cells, B cells, and plasma cells. Tocilizumab (TCZ) is the main humanized monoclonal aimed at IL-6R and appears to be a safe and possible strategy to manage ABMR in sensitized recipients. We conducted a literature review to assess the place of the anti-IL-6R monoclonal antibody TCZ within ABMR protocols.

Materials and Methods

We systematically reviewed the PubMed literature and reviewed six studies that included 117 patients and collected data on the utilization of TCZ to treat ABMR.

Results

Most studies report a significant reduction in levels of Donor Specific Antibodies (DSAs) and reduced inflammation and microvascular lesions (as found in biopsies). Stabilization of the renal function was observed. Adverse events were light to moderate, and mortality was not linked with TCZ treatment. The main side effect noted was infection, but infections did not occur more frequently in patients receiving TCZ as compared to those receiving SOC therapy.

Conclusion

TCZ may be an alternative to SOC for ABMR kidney-transplant patients, either as a first-line treatment or after failure of SOC. Further randomized and controlled studies are needed to support these results.

Early Blood Transfusion After Kidney Transplantation Does Not Lead to dnDSA Development: The BloodIm Study

Outcomes after kidney transplantation are largely driven by the development of de novo donor-specific antibodies (dnDSA), which may be triggered by blood transfusion. In this single-center study, we investigated the link between early blood transfusion and dnDSA development in a mainly anti-thymocyte globulin (ATG)-induced kidney-transplant cohort. We retrospectively included all recipients of a kidney transplant performed between 2004 and 2015, provided they had &gt;3 months graft survival. DSA screening was evaluated with a Luminex assay (Immucor). Early blood transfusion (EBT) was defined as the transfusion of at least one red blood-cell unit over the first 3 months post-transplantation, with an exhaustive report of transfusion. Patients received either anti-thymocyte globulins (ATG) or basiliximab induction, plus tacrolimus and mycophenolic acid maintenance immunosuppression. A total of 1088 patients received a transplant between 2004 and 2015 in our center, of which 981 satisfied our inclusion criteria. EBT was required for 292 patients (29.7%). Most patients received ATG induction (86.1%); the others received basiliximab induction (13.4%). dnDSA-free graft survival (dnDSA-GS) at 1-year post-transplantation was similar between EBT+ (2.4%) and EBT- (3.0%) patients (chi-squared p=0.73). There was no significant association between EBT and dnDSA-GS (univariate Cox’s regression, HR=0.88, p=0.556). In multivariate Cox’s regression, adjusting for potential confounders (showing a univariate association with dnDSA development), early transfusion remained not associated with dnDSA-GS (HR 0.76, p=0.449). However, dnDSA-GS was associated with pretransplantation HLA sensitization (HR=2.25, p=0.004), hemoglobin &gt;10 g/dL (HR=0.39, p=0.029) and the number of HLA mismatches (HR=1.26, p=0.05). Recipient’s age, tacrolimus and mycophenolic-acid exposures, and graft rank were not associated with dnDSA-GS. Early blood transfusion did not induce dnDSAs in our cohort of ATG-induced patients, but low hemoglobin level was associated with dnDSAs-GS. This suggests a protective effect of ATG induction therapy on preventing dnDSA development at an initial stage post-transplantation.

Tocilizumab in the Treatment of Chronic Antibody-Mediated Rejection Post Kidney Transplantation: Clinical and Histological Monitoring

Introduction: Chronic antibody-mediated rejection (cAMR) has very few effective therapeutic options. Interleukin-6 is an attractive target because it is involved in inflammation and humoral immunity. Therefore, the use of tocilizumab (anti-IL6 receptor, TCZ) is a potential valuable therapeutic option to treat cABMR in kidney-transplant (KT) recipients. Materials and Methods: This single-center retrospective study included all KT recipients that received monthly TCZ infusions in the setting of cABMR, between August 2018 and July 2021. We assessed 12-month renal function and KT histology during follow-up. Results: Forty patients were included. At 12-months, eGFR was not significantly different, 41.6 ± 17 vs. 43 ± 17 mL/min/1.73 m² (p = 0.102) in patients with functional graft. Six patients (15%) lost their graft: their condition was clinically more severe at the time of first TCZ infusion. Histological follow-up showed no statistical difference in the scores of glomerulitis, peritubular capillaritis, and interstitial fibrosis/tubular atrophy (IFTA). Chronic glomerulopathy score however, increased significantly over time; conversely arteritis and inflammation in IFTA ares improved in follow-up biopsies. Conclusion: In our study, the addition of TCZ prevented clinical and histological worsening of cABMR in KT recipients, except for more severely ill patients. Randomized studies are needed to clarify the risk/benefit of TCZ in cABMR.

Immune responses following tocilizumab therapy to desensitize HLA-sensitized kidney transplant candidates

Kidney transplant candidates (KTCs) who are HLA highly sensitized (calculated panel-reactive alloantibodies >95%) have poor access to deceased kidney transplantation. In this single-center prospective study, 13 highly sensitized desensitization-naïve KTCs received IV tocilizumab (8 mg/kg) every 4 weeks. We evaluated tolerability as well as immune responses, that is, T cell, B cell, T follicular helper (Tfh) subsets, blood cytokines (IL-6, soluble IL-6 receptor-sIL-6R-, IL-21), blood chemokines (CXCL10, CXCL13), and anti-HLA alloantibodies. Tocilizumab treatment was well-tolerated except in one patient who presented spondylodiscitis, raising a note of caution. Regarding immune parameters, there were no significant changes of percentages of lymphocyte subsets, that is, CD3⁺ , CD3⁺ /CD4⁺ , CD3⁺ /CD8⁺ T cells, and NK cells. This was also the case for Tfh cell subsets, B cells, mature B cells, plasma cells, pre-germinal center (GC) B cells, and post-GC B cells, whereas we observed a significant increase in naïve B cells (p = .02) and a significant decrease in plasmablasts (p = .046) over the tocilizumab treatment course. CXCL10, CXCL13, IL-21, total IgG, IgA, and IgM levels did not significantly change during tocilizumab therapy; conversely, there was a significant increase in IL-6 levels (p = .03) and a huge increase in sIL-6R (p = .00004). There was a marginal effect on anti-HLA alloantibodies (class I and class II). To conclude in highly sensitized KTCs, tocilizumab as a monotherapy limited B cell maturation; however, it had almost no effect on anti-HLA alloantibodies.

Tocilizumab Trough Levels Variability in Kidney-Transplant Candidates Undergoing Desensitization

The presence of anti-HLA antibodies is an increasing challenge in kidney transplantation. Tocilizumab (TCZ), a monoclonal antibody targeting the interleukin-6 receptor (IL-6R), has been proposed to complement conventional desensitization therapy. We aimed to describe TCZ plasma trough concentrations and their variability and to investigate the link between TCZ concentration and the evolution of anti-HLA antibodies. Sensitized kidney-transplant candidates treated monthly with TCZ (8 mg/kg) for desensitization were retrospectively included. TCZ concentrations were determined by liquid chromatography-tandem mass spectrometry. Seventy-four TCZ concentrations from 10 patients were analyzed. The TCZ trough concentration ranged from <1.0 to 52.5 mg·L−1, with a median of 25.6 mg·L−1 [25th–75th percentiles: 13.2–35.3 mg·L−1). The inter- and intra-individual coefficients of variation were 55.0% and 33.0%, respectively. The TCZ trough concentration was not related to IL-6 (rho = −0.46, p = 0.792), soluble IL-6R (rho = −0.81, p = 0.65) concentrations or reduction of anti-HLA antibodies (mixed-effects model adjusting, effect of TCZ trough concentration: rho = −0.004, p = 0.26). The individual median TCZ concentration tended to be associated with the number of antibodies, with an initial MFI > 3000 that dropped to <3000 after TCZ treatment (rho = 0.397, p = 0.083). TCZ trough concentrations in kidney-transplant candidates treated for desensitization were highly variable. Further studies on larger cohorts are needed to study the possible link between TCZ concentrations and the reduction of anti-HLA antibodies.

Belatacept Use after Kidney Transplantation and Its Effects on Risk of Infection and COVID-19 Vaccine Response

Introduction: Belatacept is a common immunosuppressive therapy used after kidney transplantation (KT) to avoid calcineurin-inhibitor (CNI) use and its related toxicities. It is unclear whether its use exposes KT recipients (KTx) to a greater risk of infection or a poorer response to vaccines. Areas covered: We reviewed PubMed and the Cochrane database. We then summarized the mechanisms and impacts of belatacept use on the risk of infection, particularly opportunistic, in two settings, i.e., de novo KTx and conversion from CNIs. We also focused on COVID-19 infection risk and response to SARS-CoV-2 vaccination in patients whose maintenance immunosuppression relies on belatacept. Expert opinion: When belatacept is used de novo, or after drug conversion the safety profile regarding the risk of infection remains good. However, there is an increased risk of opportunistic infections, mainly CMV disease and Pneumocystis pneumonia, particularly in those with a low eGFR, in older people, in those receiving steroid-based therapy, or those that have an early conversion from CNI to belatacept (i.e., <six months post-transplantation). Thus, we recommend, if possible, delaying conversion from CNI to belatacept until at least six months post-transplantation. Optimal timing seems to be eight months post-transplantation. In addition, KTx receiving belatacept respond poorly to SARS-CoV-2 vaccination.

Ten-year outcomes of islet transplantation in patients with type 1 diabetes: Data from the Swiss-French GRAGIL network

To describe the 10-year outcomes of islet transplantation within the Swiss-French GRAGIL Network, in patients with type 1 diabetes experiencing high glucose variability associated with severe hypoglycemia and/or with functional kidney graft. We conducted a retrospective analysis of all subjects transplanted in the GRAGIL-1c and GARGIL-2 islet transplantation trials and analyzed components of metabolic control, graft function and safety outcomes over the 10-year period of follow-up. Forty-four patients were included between September 2003 and April 2010. Thirty-one patients completed a 10-year follow-up. Ten years after islet transplantation, median HbA1c was 7.2% (6.2-8.0) (55 mmol/mol [44-64]) versus 8.0% (7.1-9.1) (64 mmol/mol [54-76]) before transplantation (p < .001). Seventeen of 23 (73.9%) recipients were free of severe hypoglycemia, 1/21 patients (4.8%) was insulin-independent and median C-peptide was 0.6 ng/ml (0.2-1.2). Insulin requirements (UI/kg/day) were 0.3 (0.1-0.5) versus 0.5 (0.4-0.6) before transplantation (p < .001). Median (IQR) β-score was 1 (0-4) (p < .05 when comparing with pre-transplantation values) and 51.9% recipients had a functional islet graft at 10 years. With a 10-year follow-up in a multicentric network, islet transplantation provided sustained improvement of glycemic control and was efficient to prevent severe hypoglycemia in almost 75% of the recipients.

Immortal Time-Bias-Corrected Survival of Highly Sensitized Patients and HLA-desensitized Kidney Transplant Recipients

Introduction

In the setting of kidney transplantation (KT), we assessed the efficacy of desensitization and compared the survival of desensitized patients (HLA-incompatible KT) with similarly sensitized patients receiving HLA-compatible KT or sensitized patients still on a waiting list after adjusting for the usually unaccounted immortal time bias.

Methods

All patients in a French KT center on the waiting list between August 1994 and December 2019 with a high level of sensitization (panel-reactive antibodies [PRAs] ≥80%) were included. The primary outcome was all-cause mortality. A time-varying covariate Cox survival model was used to account for the immortal time bias. A landmark analysis was used as a sensitivity analysis.

Results

During the study period, 326 patients with high PRAs were followed, among which 147 (45%) remained on the waiting list at the time of last follow-up and 179 benefited from a KT. Thirty-six patients were desensitized, of which 30 received a kidney transplant, including eight deceased kidney donors. There were no differences in mortality rates between desensitized KT patients, nondesensitized KT patients, and waitlisted patients after adjusting for immortal time bias (hazard ratio [HR] = 0.48, P = 0.22). Death-censored graft survival was similar between desensitized and nondesensitized KT patients (HR = 0.92, P = 0.88 adjusting for donor age >65 years, donor status, and time on the waiting list). Mean estimated glomerular filtration rate at 1 year post-KT was similar for desensitized KT patients (53.3 ± 21 vs. 53.6 ± 21 ml/min per 1.73 m² for nondesensitized patients; P = 0.95).

Conclusions

HLA-desensitization was effective for highly sensitized patients and gave access to KT without detrimental effects on patient or graft survival rates.

Tocilizumab and Desensitization in Kidney Transplant Candidates: Personal Experience and Literature Review

Desensitization (DES) allows kidney transplantation for highly HLA-sensitized subjects. Due to the central role of IL-6 in the immunological response, tocilizumab may improve DES efficacy. Thus, we conducted a PubMed systematic review using the MeSH terms tocilizumab, interleukin-6, kidney transplantation, and desensitization. Tocilizumab (TCZ) was first studied for DES as the second-line treatment after failure of a standard DES protocol (SP) (apheresis, rituximab +/- IVIg). Although TCZ (as a monotherapy) attenuated anti-HLA antibody rates, it did not permit transplantation. However, lymphocyte immuno-phenotyping has shown that TCZ hinders B-cell maturation and thus could improve the long-term efficacy of DES by limiting anti-HLA rebound and so avoid antibody-mediated rejection. This hypothesis is supported by a recent study where clazakizumab, a monoclonal antibody directed against IL-6, was continued after kidney transplantation in association with an SP. Nine out of ten patients were then eligible for transplantation, and there were no donor-specific antibodies at 6 months post-transplantation. In association with an SP, tocilizumab does not seem to significantly improve kidney-allograft access (short-term efficacy) vs. a SP only. However, it could improve the long-term prognosis of HLA-incompatible transplantation by hindering B-cell maturation and, thereby, avoiding donor-specific antibody rebounds post-transplantation.

Adverse effects of immunosuppression after liver transplantation

After solid organ transplantation the cornerstone of immunosuppression is based on calcineurin inhibitors (CNIs), mostly tacrolimus. However, CNIs have a very narrow therapeutic window. The most important and serious side-effects of CNIs are nephrotoxicity, high blood pressure, post-transplant diabetes mellitus (PTMD), i.e., new-onset diabetes after transplantation (NODAT), dyslipidemia, and modification to the cardiovascular-risk profile. In this review, we will focus on tacrolimus-related toxicities in the setting of liver transplantation.

Rituximab for recurrence of primary focal segmental glomerulosclerosis after kidney transplantation: Results of a nationwide study

Rituximab (RTX) therapy for primary focal segmental glomerulosclerosis recurrence after kidney transplantation (KT) has been extensively debated. We aimed to assess the benefit of adding RTX to plasmapheresis (PP), corticosteroids, and calcineurin inhibitors (standard of care, SOC). We identified 148 adult patients who received KT in 12/2004-12/2018 at 21 French centers: 109 received SOC (Group 1, G1), and 39 received immediate RTX along with SOC (Group 2, G2). In G1, RTX was introduced after 28 days of SOC in the event of failure (G1a, n = 19) or PP withdrawal (G1b, n = 12). Complete remission (CR) was achieved in 46.6% of patients, and partial remission (PR) was achieved in 33.1%. The 10-year graft survival rates were 64.7% and 17.9% in responders and nonresponders, respectively. Propensity score analysis showed no difference in CR+PR rates between G1 (82.6%) and G2 (71.8%) (p = .08). Following the addition of RTX (G1a), 26.3% of patients had CR, and 31.6% had PR. The incidence of severe infections was similar between patients treated with and without RTX. In multivariable analysis, infection episodes were associated with hypogammaglobulinemia <5 g/L. RTX could be used in cases of SOC failure or remission for early discontinuation of PP without increasing the risk of infection.

How to improve clotting factors depletion in double-filtration plasmapheresis

BACKGROUND

Double-filtration plasmapheresis (DFPP), a selective therapeutic apheresis, can deplete pathogenic antibodies/substances, but also important coagulation factors.

AIM

To determine if the use of a separator filter with different characteristics (CascadefloEC-50 W) as compared to the reference filter (PlasmafloOP-08 W) is as efficient in terms of immunoglobulin loss, but can reduce coagulation factor losses and have similar tolerability.

PATIENTS/METHODS

This is a single-center prospective study including 14 patients divided into two groups (7 each): that is, group1 = CascadefloEC-50 W and group2 = PlasmafloOP-08 W. We measured immunoglobulins, lipid profiles, blood-cell counts, hemostasis (prothrombin time, activated partial thromboplastin time), coagulation factors, and natural anticoagulants at before and after the first DFPP-session.

RESULTS

In group 1, the loss of coagulation factors was significantly reduced as compared to group 2 for proteins with a molecular weight of >150 kDa: there was, respectively, an average decrease of 70% vs 31% for fibrinogen (P = 0.004), 66% vs 21% for factor V (P = 2.16e-07), 60% vs 32% for factor XI (P = 6.96e-06), 75% vs 17% for XIII-antigen (P = 0.0002), and 47% vs 0% for VWF-antigen(P = 0.02). The decrease in post-session IgG was, on average, 45% in group 1 and 50% in group 2 (P = 0.13). Those results remained significant even when adjusted to the treated-plasma volume and the pre-DFPP factor values.

CONCLUSION

DFPP, using a CascadefloEC-50W as a first-filter, reduces efficiently IgGs similarly to PlasmafloOP-08W but spares clotting factors.

Recurrence of IgA Nephropathy after Kidney Transplantation in Adults

BACKGROUND AND OBJECTIVES

In patients with kidney failure due to IgA nephropathy, IgA deposits can recur in a subsequent kidney transplant. The incidence, effect, and risk factors of IgA nephropathy recurrence is unclear, because most studies have been single center and sample sizes are relatively small.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a multicenter, international, retrospective study to determine the incidence, risk factors, and treatment response of recurrent IgA nephropathy after kidney transplantation. Data were collected from all consecutive patients with biopsy-proven IgA nephropathy transplanted between 2005 and 2015, across 16 "The Post-Transplant Glomerular Disease" study centers in Europe, North America, and South America.

RESULTS

Out of 504 transplant recipients with IgA nephropathy, recurrent IgA deposits were identified by kidney biopsy in 82 patients; cumulative incidence of recurrence was 23% at 15 years (95% confidence interval, 14 to 34). Multivariable Cox regression revealed a higher risk for recurrence of IgA deposits in patients with a pre-emptive kidney transplant (hazard ratio, 3.45; 95% confidence interval, 1.31 to 9.17) and in patients with preformed donor-specific antibodies (hazard ratio, 2.59; 95% confidence interval, 1.09 to 6.19). After kidney transplantation, development of de novo donor-specific antibodies was associated with subsequent higher risk of recurrence of IgA nephropathy (hazard ratio, 6.65; 95% confidence interval, 3.33 to 13.27). Immunosuppressive regimen was not associated with recurrent IgA nephropathy in multivariable analysis, including steroid use. Graft loss was higher in patients with recurrence of IgA nephropathy compared with patients without (hazard ratio, 3.69; 95% confidence interval, 2.04 to 6.66), resulting in 32% (95% confidence interval, 50 to 82) graft loss at 8 years after diagnosis of recurrence.

CONCLUSIONS

In our international cohort, cumulative risk of IgA nephropathy recurrence increased after transplant and was associated with a 3.7-fold greater risk of graft loss.

[When and how to talk about living donation with a kidney failure patient ?]

When and how to talk about living donation with a kidney failure patient? Living donation is often an uneasy subject to which kidney failure patients are confronted: donation is frequently misrepresented and is object of a certain societal mistrust, making it difficult for the clinician to talk about it to patients. These obstacles can be overcome if living donation is brought up early on in the clinical course especially in the presence of the patient's family. A collegial and transparent information with a focus on demystifying misrepresentations and description of the benefits for the recipient and the donor will facilitate access to this life-changing treatment option.

Fibrinogen reconstitution after therapeutic apheresis: Comparison of double-filtration plasmapheresis, plasma exchange, and immunoadsorption

BACKGROUND

Fibrinogen reconstitution after therapeutic apheresis has been poorly studied. Apheresis modalities, for example, plasma exchange (PE), double-filtration plasmapheresis (DFPP), or selective immunoadsorption (IA), may have different impacts.

METHODS

We retrospectively investigated therapeutic apheresis sessions performed at our center across four modalities (PE, DFPP, and IA with or without plasma filtration). Fibrinogen levels were assessed at the beginning and end of each apheresis session, and immediately before the subsequent session. We adjusted measurements on hematocrit values to account for hemoconcentration.

RESULTS

Between January 10, 2016 and March 2, 2020, we included 90 patients for a total of 754 apheresis sessions (PE: 35; DFPP: 351; IA only: 109; IA + plasma filtration: 259). Each patient received a median of five sessions (1Q 3; 3Q 9); median plasma volume treated was 5.5 L (1Q 4.3 L; 3Q 7.0 L). Within a session, DFPP and PE induced a significantly greater depletion of fibrinogen than both IA modalities, even after adjustment for the treated plasma volume. Median fibrinogen reconstitution was 0.8 (0.4-1.2) g/L (median time between sessions: 38 hours). In multivariate analysis, fibrinogen reconstitution was significantly associated with intersession time (+0.66 g/L/log-hour P < .001), apheresis modality (ANOVA; P < .001), initial fibrinogen concentration (+0.15 g/L per gram of fibrinogen; P < .001), and the last fibrinogen concentration from the previous apheresis session (-0.14 g/L per gram of fibrinogen; P < .001). In a model that considered hemoconcentration, the results were unchanged.

CONCLUSIONS

We demonstrate that fibrinogen reconstitution was highly variable between patients and apheresis sessions. Apheresis modalities had a significant impact on fibrinogen reconstitution, regardless of hemoconcentration.

Treatment of antibody-mediated rejection with double-filtration plasmapheresis, low dose IVIg plus rituximab after kidney transplantation

Antibody-mediated rejection (ABMR) at early or late post-transplantation remains challenging. We performed a single-center single-arm study where four cases of acute ABMR and nine cases of chronic active ABMR (defined by Banff classification) were treated with double-filtration plasmapheresis (two cycles of three consecutive daily sessions with a 4-day gap between). At the end of the third and sixth DFPP sessions, the patients received rituximab 375 mg/m² . After a median follow-up of 1078 (61-1676) days, kidney-allograft survival was 50%. Before DFPP/rituximab therapy, the median donor-specific alloantibody (DSA) mean fluorescence intensity (MFI) was 9160 (4000-15 400); 45 days (D45) later it had significantly decreased to 7375 (215-18 100) (P = .018). In addition, at one-year (Y1) post-therapy, MFI had decreased further, that is, 4060 (400-7850) (P = .001). In two patients, DSA MFIs decreased and remained below 2000. The slope of estimated glomerular-filtration rate within the 6 months preceding intervention was -1.18 mL/min/month and remained unchanged at -1.29 mL/min/month within the year after intervention. Proteinuria remained unchanged. Baseline Banff scores on repeat allograft biopsies (post-therapy D45, Y1) did not show any improvement. Side-effects were mild to moderate. We conclude that the combined DFPP/rituximab significantly decreased DSAs in ABMR kidney-transplant recipients but did not improve renal function or renal histology at 1-year follow-up.

Apheresis Efficacy and Tolerance in the Setting of HLA-Incompatible Kidney Transplantation

Nearly 18% of patients on a waiting list for kidney transplantation (KT) are highly sensitized, which make access to KT more difficult. We assessed the efficacy and tolerance of different techniques (plasma exchanges [PE], double-filtration plasmapheresis [DFPP], and immunoadsorption [IA]) to remove donor specific antibodies (DSA) in the setting of HLA-incompatible (HLAi) KT. All patients that underwent apheresis for HLAi KT within a single center were included. Intra-session and inter-session Mean Fluorescence Intensity (MFI) decrease in DSA, clinical and biological tolerances were assessed. A total of 881 sessions were performed for 45 patients: 107 DFPP, 54 PE, 720 IA. The procedures led to HLAi KT in 39 patients (87%) after 29 (15–51) days. A higher volume of treated plasma was associated with a greater decrease of inter-session class I and II DSA (p = 0.04, p = 0.02). IA, PE, and a lower maximal DSA MFI were associated with a greater decrease in intra-session class II DSA (p < 0.01). Safety was good: severe adverse events occurred in 17 sessions (1.9%), more frequently with DFPP (6.5%) p < 0.01. Hypotension occurred in 154 sessions (17.5%), more frequently with DFPP (p < 0.01). Apheresis is well tolerated (IA and PE > DFPP) and effective at removing HLA antibodies and allows HLAi KT for sensitized patients.

Outcomes in Living Donor Kidney Transplantation: The Role of Donor's Kidney Function

INTRODUCTION

Living donor kidney transplant (LDKT) is one of the best therapeutic options for end-stage kidney disease (ESKD). Guidelines identify different estimated glomerular filtration rate (eGFR) thresholds to determine the eligibility of donors. The aim of our study was to evaluate whether pretransplant donor eGFR was associated with kidney function in the recipient.

METHODS

We retrospectively studied LDKT recipients who received a kidney graft between September 1, 2005, and June 30, 2016 in the same transplant center in France and that had eGFR data available at 3, 12, 24, and 36 months posttransplant.

RESULTS

We studied 90 donor-recipient pairs. The average age at time of transplant was 51.47 ± 10.95 for donors and 43.04 ± 13.52 years for recipients. Donors' average eGFR was 91.99 ± 15.37 mL/min/1.73 m2. Donor's age and eGFR were significantly correlated (p < 0.0001, r2 0.023). Donor's age and eGFR significantly correlated with recipient's eGFR at 3, 12, and 24 months posttransplant (age: p < 0.001 at all intervals; eGFR p = 0.001, 0.003, and 0.016, respectively); at 36 months, only donor's age significantly correlated with recipient's eGFR. BMI, gender match, and year of kidney transplant did not correlate with graft function. In the multivariable analyses, donor's eGFR and donor's age were found to be associated with graft function; correlation with eGFR was lost at 36 months; and donor's age retained a strong correlation with graft function at all intervals (p < 0.001).

CONCLUSIONS

Donor's eGFR and age are strong predictors of recipient's kidney function at 3 years. We suggest that donor's eGFR should be clinically balanced with other determinants of kidney function and in particular with age.

Comparison of three modalities of plasmapheresis on coagulation: Centrifugal, single-membrane filtration, and double-filtration plasmapheresis

BACKGROUND

Plasmapheresis can deplete pathogenic antibodies and allow ABO- and/or HLA-incompatible transplantation.

AIM

To determine the impacts of three modalities of plasmapheresis (centrifugal plasmapheresis [cTPE], single-filtration plasmapheresis [mTPE], double-filtration plasmapheresis [DFPP]) on hemostasis parameters and thrombin generation.

MATERIALS/METHODS

Prospective, comparative study on 21 patients that received three modalities of plasmapheresis (7 patients/group). Hemostasis (prothrombin time [PT], activated partial thromboplastin time [aPTT], procoagulant factors and natural anticoagulants) were measured before and after the first plasmapheresis session. Thrombin generation was also assessed in platelet-poor plasma using an STA-Genesia (Stago) analyzer and Thromboscreen reagents (Stago) in 4-5 patients from each group.

RESULTS

Both cTPE and mTPE resulted in high decreases in proteins, whatever their molecular weights. Median post/pre ratios were 0.27 to 0.55 for cTPE for most proteins (except FVIII [0.64] and VWF [0.57]). Median post/pre-ratios of mTPE were 0.28 to 0.56 for all proteins. DFPP decreased high-molecular-weight proteins (fibrinogen, FV, FVIII, FXI, VWF) and proteins strongly bound to large molecules (protein SandTFPI). Median post/pre ratios with cTPE and mTPE were similar to DFPP for fibrinogen and FXIII. Regarding thrombin generation, cTPE and mTPE did not significantly modify endogenous thrombin potential (ETP) and DFPP induced a slight decrease in ETP (median post/pre ratio at 0.73) in the absence of thrombomodulin. ETP inhibition by thrombomodulin was decreased for all procedures.

CONCLUSIONS

DFPP depleted high molecular-weight proteins in contrast to cTPE and mTPE, which significantly decreased all proteins. Regarding thrombin generation, depletion of procoagulant factors was counterbalanced by a decrease in some natural anticoagulants whatever plasmapheresis method used; with all methods, fibrinogen and FXIII were highly depleted.

A Case of Pneumocystis jirovecii Pneumonia under Belatacept and Everolimus: Benefit-Risk Balance between Renal Allograft Function and Infection

Pneumocystis jirovecii pneumonia is an opportunistic disease usually prevented by trimethoprim-sulfamethoxazole. A 49-year-old HLA-sensitized male with successful late conversion from tacrolimus-based to belatacept-based immunosuppression developed P. jirovecii pneumonia for which he presented several risks factors: low lymphocyte count with no CD4+ T cells detected since 2 years, hypogammaglobulinemia, history of acute cellular rejection 3 years before, and immunosuppressive treatment (belatacept, everolimus). Because of respiratory gravity in the acute phase, the patient was given oxygen, corticosteroids, and trimethoprim-sulfamethoxazole. Thanks to the improvement of respiratory status, and because of the renal impairment, trimethoprim-sulfamethoxazole was converted to atovaquone for 21 days. Indeed, after 1 week on intensive treatment, the benefit-risk balance favored preserving renal function according to respiratory improvement status. P. jirovecii pneumonia prophylaxis for the next 6 months was monthly aerosol of pentamidine. Long-term safety studies or early/late conversion to belatacept did not report on P. jirovecii pneumonia. Four other cases of P. jirovecii pneumonia under belatacept therapy were previously described in patients having no P. jirovecii pneumonia prophylaxis. Studies on the reintroduction of P. jiroveciipneumonia prophylaxis after conversion to belatacept would be of interest. It could be useful to continue regular evaluation within the second-year post-transplantation regarding immunosuppression: T-cell subsets and immunoglobulin G levels.

Treatment of refractory myasthenia gravis by double-filtration plasmapheresis and rituximab: A case series of nine patients and literature review

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease mediated by circulating autoantibodies (anti-AchR, anti-MuSK, etc.). More than 20% of myasthenic patients are refractory to conventional treatments (plasma exchange, IVIg, steroids, azathioprine, mycophenolate mofetil). Rituximab (B-lymphocyte-depleting anti-CD20) and apheresis (double-filtration plasmapheresis [DFPP] and immunoadsorption [IA]) are interesting therapeutic alternatives.

METHODS

This monocentric pilot study included nine refractory myasthenic patients (March 2018 to May 2020) treated by DFPP and/or IA associated with rituximab (375 mg/m² ). Clinical responses were assessed using the Myasthenia Gravis Foundation of America (MGFA) score.

RESULTS

Average age of patients was 53 ± 17 years. Gender ratio (M/F) was 3:6. The combination of apheresis and rituximab reduced median MGFA score from IV to II after 12 months of follow-up. Clinical improvement assessed by MGFA score was sustained in the long-term for all patients, during an average follow-up of 14 ± 9 months, allowing them to be self-sufficient and out sick-leave. The median number of apheresis sessions was 7 (5-30). The dose of prednisolone was reduced in two patients from 40 mg/d and 30 mg/d to 7.5 mg/d and 10 mg/d, respectively. It was stopped in a patient who was taking 30 mg/d. No infectious, bleeding, or thrombosis complications were noted.

CONCLUSION

The combination of rituximab and DFPP was effective to treat refractory MG.

Belatacept-based immunosuppressive regimen in HIV-positive kidney transplant recipients

Background

Kidney allograft survival in human immunodeficiency virus (HIV)-positive patients is lower than that in the general population. Belatacept increases long-term patient and allograft survival rates when compared with calcineurin inhibitors (CNIs). Its use in HIV-positive recipients remains poorly documented.

Methods

We retrospectively report a French cohort of HIV-positive kidney allograft recipients who were switched from CNI to belatacept, between June 2012 and December 2018. Patient and allograft survival rates, HIV immunovirological and clinical outcomes, acute rejection, opportunistic infections (OIs) and HLA donor-specific antibodies (DSAs) were analysed at 3 and 12 months, and at the end of follow-up (last clinical visit attended after transplantation). Results were compared with HIV-positive recipients group treated with CNI.

Results

Twelve patients were switched to belatacept 10 (2–25) months after transplantation. One year after belatacept therapy, patient and allograft survival rates scored 92% for both, two (17%) HIV virological rebounds occurred due to antiretroviral therapy non-compliance, and CD4⁺ and CD8⁺ T-cell counts remained stable over time. Serious adverse events included two (17%) acute steroid-resistant T-cell-mediated rejections and three (25%) OIs. Kidney allograft function significantly increased over the 12 post-switch months (P = 0.009), and DSAs remained stable at 12 months after treatment. The control group showed similar results in terms of patient and kidney allograft survival rates, DSA characteristics and proteinuria

Conclusions

Switch from CNI to belatacept can be considered safe and may increase long-term kidney allograft survival in HIV-positive kidney allograft recipients. These results need to be confirmed in a larger cohort.

pre-existing diabetes and PTDM in kidney transplant recipients: how to handle immunosuppression

INTRODUCTION

Preexisting diabetes (PD) and post-transplant diabetes mellitus (PTDM) are common and severe comorbidities posttransplantation. The immunosuppressive regimens are modifiable risk factors.

AREAS COVERED

We reviewed Pubmed and Cochrane database and we summarize the mechanisms and impacts of available immunosuppressive treatments on the risk of PD and PTDM. We also assess the possible management of these drugs to improve glycemic parameters while considering risks inherent in transplantation.

EXPERT OPINION

PD i) increases the risk of sepsis, ii) is an independent risk factor for infection-related mortality, and iii) increases acute rejection risk. Regarding PTDM development i) immunosuppressive strategies without corticosteroids significantly reduce the risk but the price may be a higher incidence of rejection; ii) minimization or rapid withdrawal of steroids are two valuable approaches; iii) the diabetogenic role of calcineurin inhibitors(CNIs) is also well-described and is more important for tacrolimus than for cyclosporine. Reducing tacrolimus-exposure may improve glycemic parameters but also has a higher risk of rejection. PTDM risk is higher in patients that receive sirolimus compared to mycophenolate mofetil. Finally, conversion from CNIs to belatacept may offer the best benefits to PTDM-recipients in terms of glycemic parameters, graft and patient-outcomes.

Isoagglutinin removal by plasma centrifugation or filtration (single or double): A prospective study in a single center

INTRODUCTION

ABO-incompatible (ABOi) kidney transplantation, a well-established procedure, has good long-term results provided pretransplant desensitization that includes immunosuppression and apheresis.

OBJECTIVE

To compare, within the first pretransplant apheresis session given to 29 ABOi kidney-transplant candidates, the effect on isoagglutinin titers (both IgG and IgM isotypes) of three modalities: centrifugation therapeutic plasmapheresis (cTP; n = 10), filtration TP (fTP; n = 9), and double-filtration plasmapheresis (DFPP; n = 10).

RESULTS

The three groups were comparable according to baseline demographics. Treated plasma volumes were similar across the three groups, that is, 4111 ± 403 mL (cTP), 3861 ± 282 mL (fTP), and 3699 ± 820 mL (DFPP): that is, 54 ± 7, 53 ± 7, and 53 ± 10 mL/kg respectively. One session of centrifugation or filtration TP reduced IgG anti-A/anti-B isoagglutinin titer by ~4, whereas one DFPP session reduced it by ~2. One session of cTP reduced IgM anti-A isoagglutinin titer by a little less than 4, whereas fTP and DFPP sessions reduced it by ~3. There were no statistical differences across the three groups regarding isoagglutinin rebound (IgG and IgM). However, isoagglutinin IgG rebound was >4 dilutions for anti-B titers compared with ~2 dilutions for anti-A titers. The median decreases in IgG level were -3.9 g/L (DFPP), -5.9 g/L (cTP), and - 6.06 g/L (fTP) (p = ns). Median fibrinogen depletions were ~ 60% (fTP), 64% (DFPP), and 76% (cTP).

CONCLUSIONS

Isoagglutinin depletions within the first apheresis session were similar across cTP, fTP, and DFPP: this was numerically lower for DFPP.

The Mayo Adhesive Probability score can help predict intra- and postoperative complications in patients undergoing laparoscopic donor nephrectomy

PURPOSE

Living donor nephrectomy is a high-stake procedure involving healthy individuals, therefore every effort should be made to define each patient's individualized risk and improve potential donors' information. The aim of this study was to evaluate the interest of the Mayo adhesive probability (MAP) score, an imaging-based score initially designed to estimate the risk of adherent perinephric fat in partial nephrectomy, to predict intra- and postoperative complications of living donor nephrectomy.

MATERIALS AND METHODS

We retrospectively reviewed the imaging, clinical, and follow-up data of 452 kidney donors who underwent laparoscopic donor nephrectomy in two academic centers.

RESULTS

Imaging and follow-up data were available for 307 kidney donors, among which 44 (14%) had a high MAP score (≥ 3). Intraoperative difficulties were encountered in 50 patients (16%), including difficult dissection (n = 35) and bleeding (n = 17). Conversion to open surgery was required for 13 patients (4.2%). On multivariate analysis, a MAP score ≥ 3 was significantly associated with the risk of intraoperative difficulty [OR 14.12 (5.58-35.7), p < 0.001] or conversion to open surgery [OR 18.96 (3.42-105.14), p = 0.0042]. Postoperative complications were noted in 99 patients (32%), including 12 patients (3.9%) with Clavien-Dindo grade III-IV complications. On multivariate analysis, a high MAP score was also associated with the risk of postoperative complications [OR 2.55 (1.20-5.40), p = 0.01].

CONCLUSIONS

In this retrospective bicentric study, a high MAP score was associated with the risk of intra- and postoperative complications of laparoscopic donor nephrectomy. The MAP score appears of interest in the living donor evaluation process to help improve donors' information and outcomes.

Opportunistic Infections and Efficacy Following Conversion to Belatacept-Based Therapy after Kidney Transplantation: A French Multicenter Cohort

Conversion from calcineurin-inhibitors (CNIs) to belatacept can help kidney-transplant (KT) recipients avoid CNI-related nephrotoxicity. The risk of associated opportunistic infections (OPIs) is ill-defined. We conducted a multicentric cohort study across 15 French KT-centers in a real-life setting. Between 07-2010 and 07-2019, 453 KT recipients were converted from CNI- to belatacept-based therapy at 19 [0.13-431] months post-transplantation. Most patients, i.e., 332 (79.3%), were converted after 6-months post-transplantation. Follow-up time after conversion was 20.1 +/- 13 months. OPIs developed in 42(9.3%) patients after 14 +/- 12 months post-conversion. Eight patients (19%) had two OPI episodes during follow-up. Incidences of CMV DNAemia and CMV disease were significantly higher in patients converted before 6-months post-KT compared to those converted later (i.e., 31.6% vs. 11.5%; p < 0.001; and 11.6% vs. 2.4%, p < 0.001, respectively). Cumulative incidence of OPIs was 6.5 OPIs/100 person-years. Incidence of CMV disease was 2.8/100 person-years, of pneumocystis pneumonia 1.6/100 person-years, and of aspergillosis 0.2/100 person-years. Multivariate analyses showed that estimated glomerular filtration (eGFR) < 25 mL/min/1.73 m² at conversion was independently associated with OPIs (HR = 4.7 (2.2 - 10.3), p < 0.001). The incidence of EBV DNAemia was 17.3 events /100 person-years. At 1-year post-conversion, mean eGFR had significantly increased from 32.0 +/- 18 mL/min/1.73 m² to 42.2 +/- 18 mL/min/1.73 m² (p < 0.0001). Conversion to belatacept is an effective strategy with a low infectious risk.

Impact of Immunosuppressive Strategies on Post-Kidney Transplantation Thrombocytopenia

BACKGROUND

Thrombocytopenia after kidney transplantation is a common complication, partly induced by immunosuppressive therapies. Peritransplant thrombocytopenia may cause serious hemorrhages. We assessed the incidence of early posttransplantation thrombocytopenia (defined as a platelet count of <150,000 mm³ or <150 G/L) in de novo kidney transplant recipients (KTRs) across 4 immunosuppressive regimens.

METHODS

This was a single-center observational study that included all consecutive KTRs who received either Thymoglobulin (THY) or Grafalon (GRA) and maintenance therapy of either mycophenolate-mofetil (MMF) or everolimus (EVR), associated with tacrolimus/corticosteroids.

RESULTS

Between July 27, 2016, and September 7, 2018, 237 KTRs were included; 64.6% experienced thrombocytopenia within the first week. Thrombocytopenia was significantly more frequent (P = .004) among GRA-treated patients (73.4%) compared to THY-treated patients (61.3%). These patients also had lower nadir platelet count (120 ± 52 vs 142 ± 48 G/L; P = .002) and lower platelet count at discharge (227 ± 94 vs 243 ± 92 G/L; P = .25). More of the GRA-EVR group had thrombocytopenia (81.0% vs 61.4% in THY-MMF, 60.9% in THY-EVR, and 69.8% in GRA-MMF; P = .081) and a worse nadir platelet count (109 ± 41 in GRA-EVR vs 141 ± 47G/L in THY-MMF, 145 ± 52 G/L in THY-EVR, and 125 ± 56 G/L in GRA-MMF; P = .011) but GRA was the only risk factor for thrombocytopenia in multivariate analyses (P = .002). Rates of hemorrhage, red blood cell transfusions, reoperations needed within the first week, delayed graft function, acute rejection, graft loss, and death did not differ between the groups after a mean follow-up of 25 ± 8 months.

CONCLUSIONS

GRA associated with EVR led to more frequent and severe thrombocytopenia, although we found no significant clinical consequences.

Transplantation in the era of the Covid-19 pandemic: How should transplant patients and programs be handled?

Due to the Covid‐19 pandemic caused by SARS‐CoV‐2, transplant programs worldwide have been severely impacted with dwindling numbers of transplantations performed and a complete halt in several areas. In this review we examine whether SARS‐CoV‐2 infection presents differently in transplant recipients, whom and how we should test, how susceptible the transplant population is to overt infection and describe the range of outcomes. From retrieved published reports on SARS‐CoV‐2infections in 389solid organ transplant recipients reported in the literature, the overall mortality rate was 16.7% (n = 65); however for those with mild or moderate Covid‐19 disease this was 2.9% and 2.3% respectively; conversely, for those with severe infection the mortality rate was 52.2%.We then address questions regarding halting transplantation programs during this pandemic, whether all human tissues being considered for transplantation are capable of transmitting the infection, and if we should alter immunosuppressive medications during the pandemic.

P1757RITUXIMAB FOR RECURRENCE OF PRIMARY FOCAL SEGMENTAL GLOMERULOSCLEROSIS AFTER KIDNEY TRANSPLANTATION: RESULTS OF A NATIONWIDE STUDY

Background and Aims

The indication of rituximab (RTX) in the treatment of primary focal segmental glomerulosclerosis (FSGS) recurrence after kidney transplantation (KT) remains controversial. The objective of our study was to evaluate the benefit and tolerability of adding RTX to the standard of care (SOC) comprising plasmapheresis (PP), corticosteroids, and high-dose anticalcineurins for the treatment of FSGS recurrence after KT.

Method

This retrospective, multicenter study reports on 148 patients, transplanted between 31 December 2004 and 31 December 2018, aged 39.9 + 13.4 years, who developed FSGS recurrence at 7 [3–23] days. In all 109 patients received a SOC (Group 1). RTX was introduced in this group after more than 28 days of SOC for failure or for therapeutic intensification (n = 19, Group 1a), or for early discontinuation of PP (n = 12, Group 1b); 39 patients received RTX associated at the outset with SOC (Group 2).

Results

We observed 46.6% complete remission (CR) and 33.1% partial remission (PR). Ten-year graft survival was 65.6% [51.4–76.6] and 13.4% [3.4–30.0] in responders and non-responders respectively. There was no difference in CR + PR rate between G1 (82.5%) and G2 (71.8%), p = 0.08, confirmed by propensity score +4.3% (95% CI [−9.0%-17.5%], p = 0.53). Following addition of RTX (Group 1a), we observed a CR rate of 26.3% and a PR rate of 31.6%. Patients with and without RTX experienced similar rejection rates (18.6% and 28.2%, p = 0.17) and infection rates (71.4% and 79.5%, p = 0.40). In multivariate analysis, the infections were associted with hypogammaglobulinemia &lt;5g/l (OR = 8.04, 95% CI [1.65,39.25], p = 0.01).

Conclusion

Rituximab could be used in cases of SOC failure or in remission patients for early weaning of plasmapheresis, without increasing infectious risk.

Transplantation of Marginal Organs: Immunological Aspects and Therapeutic Perspectives in Kidney Transplantation

Recent data from the World Population Prospects projects that, by 2050, nearly all regions in the world will have a quarter or more of the population aged 60 and above. Chronic kidney disease (CKD) has a high global prevalence (~13%) worldwide, and the prevalence of chronic kidney disease and end-stage kidney disease increase with age. Kidney transplantation remains the best therapeutic option for end-stage kidney disease, offering a survival benefit in comparison with dialysis maintenance for most patients. This review focuses on immunological aspects of kidney transplantation in older patients and marginal donors, i.e., 60 years or older deceased kidney donors or 50–59 years old deceased kidney donors with comorbidities. Clinical outcomes of kidney recipients in terms of renal and patient survival are more than acceptable even for patients over 70. In this population, the first cause of graft loss is death with a functional graft. However, the inherent issues of these transplantations are the acceptance or refusal of frail kidney from an old donor and the increased immunogenicity of these organs in balance with potential frail and immunosenescent recipients. Finally, the immunosuppressive regimen itself is a challenge for the future of the transplant, to prevent adverse effects such as nephrotoxicity and higher risk of infections or cancer in a population already at risk. Belatacept may have a good place in the immunosuppressive strategy to improve efficacy and the safety posttransplantation.

Recurrence of FSGS after Kidney Transplantation in Adults

BACKGROUND AND OBJECTIVES

FSGS recurrence after kidney transplantation is a major risk factor for graft loss. However, the natural history, clinical predictors, and response to treatment remain unclear because of small sample sizes and poor generalizability of single-center studies, and disease misclassification in registry-based studies. We therefore aimed to determine the incidence, predictors, and treatment response of recurrent FSGS in a large cohort of kidney transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Post-Transplant Glomerular Disease (TANGO) project is an observational, multicenter, international cohort study that aims to investigate glomerular disease recurrence post-transplantation. Transplant recipients were screened for the diagnosis of idiopathic FSGS between 2005 and 2015 and details were recorded about the transplant, clinical outcomes, treatments, and other risk factors.

RESULTS

Among 11,742 kidney transplant recipients screened for FSGS, 176 had a diagnosis of idiopathic FSGS and were included. FSGS recurred in 57 patients (32%; 95% confidence interval [95% CI], 25% to 39%) and 39% of them lost their graft over a median of 5 (interquartile range, 3.0-8.1) years. Multivariable Cox regression revealed a higher risk for recurrence with older age at native kidney disease onset (hazard ratio [HR], 1.37 per decade; 95% CI, 1.09 to 1.56). Other predictors were white race (HR, 2.14; 95% CI, 1.08 to 4.22), body mass index at transplant (HR, 0.89 per kg/m²; 95% CI, 0.83 to 0.95), and native kidney nephrectomies (HR, 2.76; 95% CI, 1.16 to 6.57). Plasmapheresis and rituximab were the most frequent treatments (81%). Partial or complete remission occurred in 57% of patients and was associated with better graft survival.

CONCLUSIONS

Idiopathic FSGS recurs post-transplant in one third of cases and is associated with a five-fold higher risk of graft loss. Response to treatment is associated with significantly better outcomes but is achieved in only half of the cases.