Translational research and innovation in modern transplant practice: Paradigms from Greece and around the world

The continuous clinical and technological advances, together with the social, health and economic challenges that the global population faces, have created an environment where the evolution of the field of transplantation is essentially necessary. The goal of this special issue is to provide a picture of the current status of transplantation in Greece as well as in many other countries in Europe and around the world. Authors from Greece and several other countries provide us with valuable insight into their respective areas of transplant expertise, with a main focus on the field of translational research and innovation. The papers that are part of this Special Issue “Translational Research and Innovation and the current status of Transplantation in Greece” have presented innovative and meaningful approaches in modern transplant research and practice. They provide us with a clear overview of the current landscape in transplantation, including liver transplantation in the context of a major pandemic, the evolution of living donor kidney transplantation or the evolution of the effect of hepatitis C virus infection in transplantation, while at the same time explore more recent challenges, such as the issue of frailty in the transplant candidate and the changes brought by newer treatments, such as immunotherapy, in transplant oncology. Additionally, they offer us a glimpse of the effect that technological innovations, such as virtual reality, can have on transplantation, both in terms of clinical and educational aspects. Just as critical is the fact that this Special Issue emphasizes the multidisciplinary, collaborative efforts currently taking place that link transplant research and innovation with other cutting-edge disciplines such as bioengineering, advanced information technology and artificial intelligence. In this Special Issue, in addition to the clinical and research evolution of the field of transplantation, we are witnessing the importance of interdisciplinary collaboration in medicine.

Hypertension in kidney transplant recipients

Kidney transplantation is considered the treatment of choice for end-stage kidney disease patients. However, the residual cardiovascular risk remains significantly higher in kidney transplant recipients (KTRs) than in the general population. Hypertension is highly prevalent in KTRs and represents a major modifiable risk factor associated with adverse cardiovascular outcomes and reduced patient and graft survival. Proper definition of hypertension and recognition of special phenotypes and abnormal diurnal blood pressure (BP) patterns is crucial for adequate BP control. Misclassification by office BP is commonly encountered in these patients, and a high proportion of masked and uncontrolled hypertension, as well as of white-coat hypertension, has been revealed in these patients with the use of ambulatory BP monitoring. The pathophysiology of hypertension in KTRs is multifactorial, involving traditional risk factors, factors related to chronic kidney disease and factors related to the transplantation procedure. In the absence of evidence from large-scale randomized controlled trials in this population, BP targets for hypertension management in KTR have been extrapolated from chronic kidney disease populations. The most recent Kidney Disease Improving Global Outcomes 2021 guidelines recommend lowering BP to less than 130/80 mmHg using standardized BP office measurements. Dihydropyridine calcium channel blockers and angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers have been established as the preferred first-line agents, on the basis of emphasis placed on their favorable outcomes on graft survival. The aim of this review is to provide previous and recent evidence on prevalence, accurate diagnosis, pathophysiology and treatment of hypertension in KTRs.

Head-To-Head Comparison of Response Rates to the Two mRNA SARS-CοV-2 Vaccines in a Large Cohort of Solid Organ Transplant (SOT) Recipients

Due to their higher risk of developing life-threatening COVID-19 disease, solid organ transplant (SOT) recipients have been prioritized in the vaccination programs of many countries. However, there is increasing evidence of reduced immunogenicity to SARS-CοV-2 vaccination. The present study investigated humoral response, safety, and effectiveness after the two mRNA vaccines in 455 SOT recipients. Overall, the antibody response rate was low, at 39.6%. Higher immunogenicity was detected among individuals vaccinated with the mRNA1273 compared to those with the BNT162b2 vaccine (47% vs. 36%, respectively, p = 0.025) as well as higher median antibody levels of 31 (7, 372) (AU/mL) vs. 11 (7, 215) AU/mL, respectively. Among the covariates assessed, vaccination with the BNT162b2 vaccine, antimetabolite- and steroid-containing immunosuppression, female gender, the type of transplanted organ and older age were factors that negatively influenced immune response. Only mild adverse effects were observed. Our findings confirm poor immunogenicity after vaccination, implicating a reevaluation of vaccination policy in SOT recipients.

A Systematic Review of COVID-19 Infection in Kidney Transplant Recipients: A Universal Effort to Preserve Patients' Lives and Allografts

The coronavirus disease 2019 (COVID-19) pandemic has posed a significant challenge to physicians and healthcare systems worldwide. Evidence about kidney transplant (KTx) recipients is still limited. A systematic literature review was performed. We included 63 articles published from 1 January until 7 July 2020, reporting on 420 adult KTx recipients with confirmed COVID-19. The mean age of patients was 55 ± 15 years. There was a male predominance (67%). The majority (74%) were deceased donor recipients, and 23% were recently transplanted (<1 year). Most patients (88%) had at least one comorbidity, 29% had two, and 18% three. Ninety-three percent of cases were hospitalized. Among them, 30% were admitted to the intensive care unit, 45% developed acute respiratory distress syndrome, and 44% had acute kidney injury with 23% needing renal replacement therapy. From the hospitalized patients a total of 22% died, 59% were discharged, and 19% were still in hospital at the time of publication. Immunosuppression was reduced in 27%, discontinued in 31%, and remained unchanged in 5%. Hydroxychloroquine was administered to 78% of patients, antibiotics to 73%, and antivirals to 30% while 25% received corticosteroid boluses, 28% received anti-interleukin agents, and 8% were given immunoglobulin. The main finding of our analysis was that the incidence of COVID-19 among kidney transplant patients is not particularly high, but when they do get infected, this is related to significant morbidity and mortality.

A case report of hypocomplementemic urticarial vasculitis presenting with membranoproliferative glomerulonephritis

Background

Hypocomplementemic urticarial vasculitis syndrome is an infrequent condition characterized by ocular, renal, gastrointestinal and pulmonary involvement with low serum complement levels and autoantibodies. Renal manifestations vary from microscopic hematuria to nephrotic syndrome and acute kidney injury. Accordingly differing histologic patterns have been reported.

Case presentation

We present the case of a 65 years old woman with a history of chronic uveitis who presented with arthralgias, urticarial rush, nephrotic syndrome, glomerular hematuria and low serum complement. Kidney biopsy revealed an immune-complex membranoproliferative glomerulonephritis. The patient received induction therapy with steroids, cyclophosphamide and hydroxychloroquine followed by rapid clinical improvement and remission of proteinuria. Maintenance treatment consisted of rituximab pulses.

Conclusions

The majority of hypocomplementemic urticarial vasculitis syndrome cases is idiopathic, although an association to drugs, infections or other autoimmune disorders has been recorded. Given the rarity and heterogeneity of the disease, no standard treatment is established.

A Patient with Cryoglobulinemic Membranoproliferative GN (MPGN) Who Survived COVID-19 Disease: Case Presentation and Current Data of COVID-19 Infection in Dialysis and Transplanted Patients in Greece

The evolving pandemic of Coronavirus Disease 2019 has posed a substantial health risk worldwide. However, there is a paucity of data regarding the clinical course and the therapeutic management of patients with chronic kidney disease and COVID-19 infection. To date, most evidence has come from renal transplantation, with about 45 patients reported thus far, and the current data from the ERA-EDTA (ERACODA) registry for transplanted patients and patients on Renal Replacement Therapy (RRT); as for those with glomerular diseases, data are lacking. Herein, we report the case of a 62-year-old patient with severe membranoproliferative glomerulonephritis who had been receiving a high burden of immunosuppression until four months before the COVID-19 infection. He developed severe disease with acute respiratory failure requiring mechanical ventilation. After treatment with hydroxychloroquine and azithromycin, despite his low chances, he gradually recovered and survived. To the best of our knowledge, this is one of the few reported patients with glomerulonephritis who had COVID-19 Besides our single case with glomerulonephritis early during the disease outbreak, the very low prevalence of COVID-19 infection in the country’s transplant recipients (0.038%) and dialysis patients (0.24%) reflects the impact of the rapid implementation of social distancing rules as well as of preventive measures for disease control in the hospitals and dialysis units in our country.

Glomerular Diseases and Renal Transplantation: Pathogenic Pathways and Evolution of Therapeutic Interventions

Glomerular diseases and renal transplantation are the main fields of nephrology in which the immune system plays a prevalent role. Glomerular diseases have traditionally been attributed to auto-immune conditions, whereas allograft rejection has been considered an allo-immune response. However, common immunopathologic mechanisms that include Toll-like receptors, complement and B-cell activation, as well as genetic and infectious factors appear to be involved in the pathogenesis of both entities. Novel therapeutic regimens directed against specific targets of the immune system show promising results in glomerulopathies as well as in renal transplantation.

Excellent long term patient and renal allograft survival after ABO-incompatible kidney transplantation: Experience of one center

AIM: To investigate the long-term results of ABO-incompatible (ABOi) kidney transplantation in a single center in Greece.

METHODS: Thirty consecutive ABOi kidney transplantations were performed from June 2005 to December 2013. All patients received rituximab one month prior to transplantation. Immunoadsorption therapy was performed for the removal of anti-A/B IgG antibodies until the titer was ≤ 1:16. Additional apheresis sessions were performed post-operatively. Intravenous immunoglobulin and oral immunosuppression consisting of tacrolimus (TAC) in combination with either everolimus or mycophenolate acid was administered. We compared the long term results of our ABOi group to those of a matched group of 30 ABO compatible (ABOc) living kidney recipients with similar baseline characteristics. The ABOc recipients received an immunosuppressive regimen consisting of TAC and mycophenolate acid. All patients in both groups received induction therapy with Basiliximab or Daclizumab, whereas corticosteroids were instituted on the day of surgery. During the follow-up period, indication biopsies were performed and interpreted by an experienced nephropathologist. The parameters we analyzed included the following: Donor/recipient age, gender, blood type, human leukocyte antigen mismatches, panel reactive antibodies, primary cause of renal failure, mean time on dialysis, immunosuppressive regimen, patient survival, graft outcome, incidence of rejections, surgical and infectious complications.

RESULTS: The mean follow-up period was 6 years (range 1 to 9 years). A mean of 5.0 ± 3.0 (range 0-14) pre-transplant immunoadsorptions were required in order to reach the target titer. Patient survival in ABOi group in comparison to ABOc group at 1, 3, 5 and 8 years did not differ significantly (100% vs 100%, 96% vs 100%, 92% vs 100% and 92% vs 100%, P = ns). Additionally, graft survival was similar in the two groups at the same time points (100% vs 100%, 96% vs 96%, 92% vs 96% and 81% vs 92%, P = ns). The mean serum creatinine and the estimated glomerular filtration rate by the modification of diet in renal disease formula at 1, 3, 5 and 8 years did not differ significantly between ABOi and ABOc group. None of the patients in the ABOi group developed acute or chronic antibody-mediated rejection evidenced by histological signs. Four patients (13.3%) in the ABOi group and 3 (10%) in the ABOc group experienced acute cellular rejection, which was treated successfully in all cases. Bacterial and viral infections were also similar between the two groups.

CONCLUSION: ABOi kidney transplantation is a safe and effective alternative that enables kidney transplantation in countries with unacceptably long deceased-donor waiting lists.

Incidence and risk factors of herpes zoster among adult renal transplant recipients receiving universal antiviral prophylaxis

Background

Herpes zoster (HZ) is a significant cause of morbidity and complications in adult renal transplant recipients. We determined the incidence, complications and risk factors for the development of HZ after renal transplantation in a setting using universal antiviral prophylaxis.

Methods

The medical files of all adult renal transplants, performed between 2004 and 2008, were retrospectively reviewed to assess the clinical characteristics and risk factors of HZ. Incident cases of HZ were determined and the probability of developing post-transplant HZ for all subjects was calculated using the Kaplan Meier method. A multivariable Cox proportional hazards model was applied to assess the risk factors associated with the development of HZ.

Results

A total of 450 patients were eligible with a median follow up of 38 months. Twenty nine subjects (6.4 %) developed HZ, the median time to onset was 18 months, only three of them (10.3 %) required hospitalization, and none developed disseminated or visceral disease and death directly attributed to zoster. However, high rates of post-herpetic neuralgia (48.7 %) were observed. Overall incidence was calculated at 20.6 cases per 1000 patient-years of follow-up. Following multivariate analysis, increased age ≥ 60 years old, positive pre-transplant history of varicella related disease and administration of rejection treatment conferred an increased risk of 4.00-fold (CI: 1.79- 8.92), 16.00-fold (CI: 4.62- 55.52), and 5.57-fold (CI: 1.56- 19.84) respectively, for the development of post-transplant zoster.

Conclusions

HZ remains a common complication after renal transplantation in adults under current immunosuppession protocols and universal antiviral prophylaxis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1038-1) contains supplementary material, which is available to authorized users.

Glomerular disease recurrence in the renal allograft: a hurdle but not a barrier for successful kidney transplantation

Almost all forms of primary as well as secondary glomerulonephritides may recur after renal transplantation. Recurrence of the original disease is now the third most common cause of late allograft loss. Nevertheless, in most cases it is difficult to assess the true impact of primary disease recurrence in the allograft; histological recurrence with mild features does not necessarily implicate clinically severe disease. Moreover it is often difficult to distinguish recurrent from de novo disease as in membranous glomerulopathy. Because recurrence occurs late, histological lesions of recurrent glomerulonephritis may be unmasked by chronic damage from other causes such as chronic rejection. Beside the difficulties to interpret renal histology due to the variety of allograft lesions, there are no well-established options to prevent clinically severe disease recurrence nor the therapeutic approaches to the problem. The purpose of this review was mainly to underline that almost all primary and secondary glomerulonephritides represent a contraindication to transplantation. For the majority of patients with end-stage renal disease due to glomerulonephritis, transplantation still represents the treatment of choice.

Rituximab and mycophenolate mofetil for relapsing proliferative lupus nephritis: a long-term prospective study

BACKGROUND

Subsequent to cyclophosphamide-based induction therapy of lupus nephritis, and despite maintenance chronic immunosuppressive treatment, many patients experience relapses.

METHODS

This prospective, observational study included 10 women with biopsy-proven relapse of proliferative lupus nephritis occurring during maintenance with mycophenolate mofetil (MMF) or azathioprine. The long-term outcome after a single course of the B-cell depleting anti-CD20 antibody rituximab (4 weekly infusions of 375 mg/m(2)), combined with daily MMF (2 g) and prednisolone (0.5 mg/ kg/day for 4 weeks, tapered thereafter) is presented.

RESULTS

While renal function was not severely impaired at baseline, partial remission (>50% improvement in all abnormal renal parameters) was achieved in eight patients at a median of 3.5 months. In seven patients, with 24-h urinary protein of 2.5 +/- 1.1 g (mean +/- SD), complete remission, associated with increases in serum complement levels and decreases in anti-dsDNA titres, was subsequently established (normal serum creatinine/albumin levels, inactive urine sediment and 24-h urinary protein <0.5 g). Complete nephritis remission was sustained at the follow-up end (median of 38 months) in six patients. Combination treatment was well tolerated.

CONCLUSIONS

The efficacy of this low-toxicity combination was particularly evident in patients with subnephrotic proteinuria due to proliferative lupus nephritis relapse. Controlled trials to define the role of rituximab/MMF in this condition are warranted.