Antibody-mediated rejection (AMR) is caused by antibodies that recognize donor human leukocyte antigen (HLA) or other targets. As knowledge of AMR pathophysiology has increased, a combination of factors is necessary to confirm the diagnosis and phenotype. However, frequent modifications to the AMR definition have made it difficult to compare data and evaluate associations between AMR and graft outcome. The present paper was developed following a Broad Scientific Advice request from the European Society for Organ Transplantation (ESOT) to the European Medicines Agency (EMA), which explored whether updating guidelines on clinical trial endpoints would encourage innovations in kidney transplantation research. ESOT considers that an AMR diagnosis must be based on a combination of histopathological factors and presence of donor-specific HLA antibodies in the recipient. Evidence for associations between individual features of AMR and impaired graft outcome is noted for microvascular inflammation scores ≥2 and glomerular basement membrane splitting of >10% of the entire tuft in the most severely affected glomerulus. Together, these should form the basis for AMR-related endpoints in clinical trials of kidney transplantation, although modifications and restrictions to the Banff diagnostic definition of AMR are proposed for this purpose. The EMA provided recommendations based on this Broad Scientific Advice request in December 2020; further discussion, and consensus on the restricted definition of the AMR endpoint, is required.

The impact of corticosteroid withdrawal on medium-term graft histological changes in kidney transplant (KT) recipients under standard immunosuppression is uncertain. As part of an open-label, multicenter, prospective, phase IV, 24-month clinical trial (ClinicalTrials.gov, NCT02284464) in low-immunological-risk KT recipients, 105 patients were randomized, after a protocol-biopsy at 3 months, to corticosteroid continuation (CSC, n = 52) or corticosteroid withdrawal (CSW, n = 53). Both groups received tacrolimus and MMF and had another protocol-biopsy at 24 months. The acute rejection rate, including subclinical inflammation (SCI), was comparable between groups (21.2 vs. 24.5%). No patients developed dnDSA. Inflammatory and chronicity scores increased from 3 to 24 months in patients with, at baseline, no inflammation (NI) or SCI, regardless of treatment. CSW patients with SCI at 3 months had a significantly increased chronicity score at 24 months. HbA1c levels were lower in CSW patients (6.4 ± 1.2 vs. 5.7 ± 0.6%; p = 0.013) at 24 months, as was systolic blood pressure (134.2 ± 14.9 vs. 125.7 ± 15.3 mmHg; p = 0.016). Allograft function was comparable between groups and no patients died or lost their graft. An increase in chronicity scores at 2-years post-transplantation was observed in low-immunological-risk KT recipients with initial NI or SCI, but CSW may accelerate chronicity changes, especially in patients with early SCI. This strategy did, however, improve the cardiovascular profiles of patients.

The impact of human leukocyte antigen (HLA)-mismatching on the early appearance of subclinical inflammation (SCI) in low-immunological-risk kidney transplant (KT) recipients is undetermined. We aimed to assess whether HLA-mismatching (A-B-C-DR-DQ) is a risk factor for early SCI. As part of a clinical trial (Clinicaltrials.gov, number NCT02284464), a total of 105 low-immunological-risk KT patients underwent a protocol biopsy on the third month post-KT. As a result, 54 presented SCI, showing a greater number of total HLA-mismatches (p = 0.008) and worse allograft function compared with the no inflammation group (48.5 ± 13.6 vs. 60 ± 23.4 mL/min; p = 0.003). Multiple logistic regression showed that the only risk factor associated with SCI was the total HLA-mismatch score (OR 1.32, 95%CI 1.06-1.64, p = 0.013) or class II HLA mismatching (OR 1.51; 95%CI 1.04-2.19, p = 0.032) after adjusting for confounder variables (recipient age, delayed graft function, transfusion prior KT, and tacrolimus levels). The ROC curve illustrated that the HLA mismatching of six antigens was the optimal value in terms of sensitivity and specificity for predicting the SCI. Finally, a significantly higher proportion of SCI was seen in patients with >6 vs. ≤6 HLA-mismatches (62.3 vs. 37.7%; p = 0.008). HLA compatibility is an independent risk factor associated with early SCI. Thus, transplant physicians should perhaps be more aware of HLA mismatching to reduce these early harmful lesions.

Improving cytomegalovirus (CMV) immune-risk stratification in kidney transplantation is highly needed to establish guided preventive strategies.

This prospective, interventional, multicenter clinical trial assessed the value of monitoring pretransplant CMV-specific cell-mediated immunity (CMI) using an interferon-γ release assay to predict CMV infection in kidney transplantation. One hundred sixty donor/recipient CMV-seropositive (D+/R+) patients, stratified by their baseline CMV (immediate-early protein 1)-specific CMI risk, were randomized to receive either preemptive or 3-month antiviral prophylaxis. Also, 15-day posttransplant CMI risk stratification and CMI specific to the 65 kDa phosphoprotein (pp65) CMV antigen were investigated. Immunosuppression consisted of basiliximab, tacrolimus, mycophenolate mofetil, and corticosteroids in 80% of patients, whereas 20% received thymoglobulin induction therapy.

Patients at high risk for CMV based on pretransplant CMI developed significantly higher CMV infection rates than those deemed to be at low risk with both preemptive (73.3% vs 44.4%; odds ratio [OR], 3.44 [95% confidence interval {CI}, 1.30-9.08]) and prophylaxis (33.3% vs 4.1%; OR, 11.75 [95% CI, 2.31-59.71]) approaches. The predictive capacity for CMV-specific CMI was only found in basiliximab-treated patients for both preemptive and prophylaxis therapy. Fifteen-day CMI risk stratification better predicted CMV infection (81.3% vs 9.1%; OR, 43.33 [95% CI, 7.89-237.96]).

Pretransplant CMV-specific CMI identifies D+/R+ kidney recipients at high risk of developing CMV infection if not receiving T-cell-depleting antibodies. Monitoring CMV-specific CMI soon after transplantation further defines the CMV infection prediction risk. Monitoring CMV-specific CMI may guide decision making regarding the type of CMV preventive strategy in kidney transplantation.

NCT02550639.

Kidney transplant recipients might be at higher risk for severe coronavirus disease 2019 (COVID-19). However, risk factors for relevant outcomes remain uncertain in this population. This is a multicentric kidney transplant cohort including 104 hospitalized patients between March 4 and April 17, 2020. Risk factors for death and acute respiratory distress syndrome (ARDS) were investigated, and clinical and laboratory data were analyzed. The mean age was 60 years. Forty-seven patients (54.8%) developed ARDS. Obesity was associated to ARDS development (OR 2.63; P = .04). Significant age differences were not found among patients developing and not developing ARDS (61.3 vs 57.8 years, P = .16). Seventy-six (73%) patients were discharged, and 28 (27%) died. Death was more common among the elderly (55 and 70.8 years, P < .001) and those with preexisting pulmonary disease (OR 2.89, P = .009). At admission, higher baseline lactate dehydrogenase (257 vs 358 IU/mL, P = .001) or ARDS conferred higher risk of death (HR 2.09, P = .044). In our cohort, ARDS was equally present among young and old kidney recipients. However, the elderly might be at higher risk of death, along with those showing higher baseline LDH at admission.

With the development of modern solid-phase assays to detect anti-HLA antibodies and a more precise histological classification, the diagnosis of antibody-mediated rejection (AMR) has become more common and is a major cause of kidney graft loss. Currently, there are no approved therapies and treatment guidelines are based on low-level evidence. The number of prospective randomized trials for the treatment of AMR is small, and the lack of an accepted common standard for care has been an impediment to the development of new therapies. To help alleviate this, The Transplantation Society convened a meeting of international experts to develop a consensus as to what is appropriate treatment for active and chronic active AMR. The aim was to reach a consensus for standard of care treatment against which new therapies could be evaluated. At the meeting, the underlying biology of AMR, the criteria for diagnosis, the clinical phenotypes, and outcomes were discussed. The evidence for different treatments was reviewed, and a consensus for what is acceptable standard of care for the treatment of active and chronic active AMR was presented. While it was agreed that the aims of treatment are to preserve renal function, reduce histological injury, and reduce the titer of donor-specific antibody, there was no conclusive evidence to support any specific therapy. As a result, the treatment recommendations are largely based on expert opinion. It is acknowledged that properly conducted and powered clinical trials of biologically plausible agents are urgently needed to improve patient outcomes.

Despite the high incidence of posttransplant diabetes mellitus (PTDM) among high-risk recipients, no studies have investigated its prevention by immunosuppression optimization.

We conducted an open-label, multicenter, randomized trial testing whether a tacrolimus-based immunosuppression and rapid steroid withdrawal (SW) within 1 week (Tac-SW) or cyclosporine A (CsA) with steroid minimization (SM) (CsA-SM), decreased the incidence of PTDM compared with tacrolimus with SM (Tac-SM). All arms received basiliximab and mycophenolate mofetil. High risk was defined by age >60 or >45 years plus metabolic criteria based on body mass index, triglycerides, and high-density lipoprotein-cholesterol levels. The primary endpoint was the incidence of PTDM after 12 months.

The study comprised 128 de novo renal transplant recipients without pretransplant diabetes (Tac-SW: 44, Tac-SM: 42, CsA-SM: 42). The 1-year incidence of PTDM in each arm was 37.8% for Tac-SW, 25.7% for Tac-SM, and 9.7% for CsA-SM (relative risk [RR] Tac-SW vs. CsA-SM 3.9 [1.2-12.4; P = 0.01]; RR Tac-SM vs. CsA-SM 2.7 [0.8-8.9; P = 0.1]). Antidiabetic therapy was required less commonly in the CsA-SM arm (P = 0.06); however, acute rejection rate was higher in CsA-SM arm (Tac-SW 11.4%, Tac-SM 4.8%, and CsA-SM 21.4% of patients; cumulative incidence P = 0.04). Graft and patient survival, and graft function were similar among arms.

In high-risk patients, tacrolimus-based immunosuppression with SM provides the best balance between PTDM and acute rejection incidence.

There are no approved treatments for chronic antibody mediated rejection (ABMR). We conducted a multicenter, prospective, randomized, placebo-controlled, double-blind clinical trial to evaluate efficacy and safety of intravenous immunoglobulins (IVIG) combined with rituximab (RTX) (EudraCT 2010-023746-67). Patients with transplant glomerulopathy and anti-HLA donor-specific antibodies (DSA) were eligible. Patients with estimated glomerular filtration rate (eGFR) <20 mL/min per 1.73m2 and/or severe interstitial fibrosis/tubular atrophy were excluded. Patients were randomized to receive IVIG (4 doses of 0.5 g/kg) and RTX (375 mg/m2 ) or a wrapped isovolumetric saline infusion. Primary efficacy variable was the decline of eGFR at one year. Secondary efficacy variables included evolution of proteinuria, renal lesions, and DSA at 1 year. The planned sample size was 25 patients per group. During 2012-2015, 25 patients were randomized (13 to the treatment and 12 to the placebo group). The planned patient enrollment was not achieved because of budgetary constraints and slow patient recruitment. There were no differences between the treatment and placebo groups in eGFR decline (-4.2 ± 14.4 vs. -6.6 ± 12.0 mL/min per 1.73 m2 , P-value = .475), increase of proteinuria (+0.9 ± 2.1 vs. +0.9 ± 2.1 g/day, P-value = .378), Banff scores at one year and MFI of the immunodominant DSA. Safety was similar between groups. These data suggest that the combination of IVIG and RTX is not useful in patients displaying transplant glomerulopathy and DSA.

Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs available for transplant. The clinical transplant community needs to identify and manage those patient modifiable factors, to decrease the risk of graft failure, and improve longer-term outcomes.COMMIT was formed in 2015 and is composed of 20 leading kidney and liver transplant specialists from 9 countries across Europe. The group's remit is to provide expert guidance for the long-term management of kidney and liver transplant patients, with the aim of improving outcomes by minimizing modifiable risks associated with poor graft and patient survival posttransplant.The objective of this supplement is to provide specific, practical recommendations, through the discussion of current evidence and best practice, for the management of modifiable risks in those kidney and liver transplant patients who have survived the first postoperative year. In addition, the provision of a checklist increases the clinical utility and accessibility of these recommendations, by offering a systematic and efficient way to implement screening and monitoring of modifiable risks in the clinical setting.