Common infections in kidney transplant recipients

Infective endocarditis with metastatic infections in a renal transplant recipient: a case report

BACKGROUND

Infective endocarditis is an uncommon but well-known post-transplant complication with significant morbidity and mortality. It has been observed to be about 171 times more common in solid organ transplant patients than in the general population. With the increasing rate of end-stage kidney disease, the higher demand for kidney transplantation with better graft survival, and life expectancy rates, more transplant recipients may develop infective endocarditis as a late post-transplant complication. Prompt diagnosis of infective endocarditis is therefore necessary to avert graft loss and other life-threatening outcomes.

CASE PRESENTATION

We present a case of a 52-year-old African patient who had a live donor kidney transplant 18 months prior to presentation and had been on oral tacrolimus 5 mg every morning/4.5 mg every evening, mycophenolic acid (MPA) 720 mg twice daily, and oral prednisolone 10 mg daily as maintenance immunosuppressive medications. Regarding the above immunosuppressive medications, he had been in good health and had a functioning transplant graft. He presented with a resolving right thigh swelling, recurrence of fever, new onset left hemiplegia, and seizures. Enterococcus faecalis infective endocarditis was diagnosed with metastatic brain abscesses, which was treated with intravenous vancomycin and gentamycin for 5 weeks. There are very few reported cases of infective endocarditis due to Enterococcus faecalis, and this case is unique because the initial presentation was pyomyositis.

CONCLUSION

Infective endocarditis with septic embolization to the brain should be considered in kidney transplant recipients with pyomyositis and multiple rim-enhancing lesions, especially in the late post-transplant period with Enterococcal spp. as an emerging cause of infective endocarditis in kidney transplant recipients. Clinicians will need to have a high index of suspicion to aid early diagnosis with appropriate treatment to prevent adverse outcomes.

Nitrofurantoin as an Add-On to Conventional Prophylaxis for the Treatment of Urinary Tract Infections in Kidney Recipients: A Prospective Cohort Study

Urinary tract infections (UTIs) constitute one of the main complications in kidney recipients, increasing both morbidity and mortality. Due to the resurgence of antimicrobial resistance, new prophylactic approaches are being investigated. Nitrofurantoin is an antibiotic from the nitrofuran group that is effective against several Gram-negative and Gram-positive organisms; hence, there has been a resurgence in its prescription for treating MDR pathogens. Objectives: This study aims to assess the effectiveness of nitrofurantoin as an add-on to conventional therapy (amikacin + ceftriaxone or cefotaxime) for the treatment of urinary tract infections in kidney recipients. Methods: In a prospective cohort study, we included patients who received a kidney in a tertiary-care hospital. According to the intensive care specialist, group 1 patients were treated with the conventional prophylactic treatment plus nitrofurantoin as an add-on. Group 2 patients were treated only with the conventional prophylactic treatment. They were followed-up for 3 months, and the incidence of urinary tract infections was reported. Results: The UTI incidence for group 1 at 3 months was 20.6%, and for group 2, it was 20.0%; no statistical difference between treatments was observed (p = 0.9). The most commonly isolated pathogens were E. coli (28.5) and K. pneumonie (28.5%). The factor most associated with developing a UTI was female gender (aHR: 7.0; 95% IC 2.3-20.9, p < 0.001). Conclusions: In our cohort study, nitrofurantoin as an add-on in conventional therapy did not prove to be effective in preventing UTI development; therefore, other treatment options should be considered as a part of prophylactic treatment.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

High-Dose Intravenous Immunoglobulin to Treat Anti-Thymocyte Globulin Induction-Related BK Virus and Cytomegalovirus Infection in Patients with ABO-Incompatible Kidney Transplantation

BACKGROUND

ABO-incompatible (ABOi) transplantation is a novel method transplantation method that carries a heightened risk of infection caused by the use of high immunosuppressant doses. This elevated risk is particularly concerning for viral infections, such as cytomegalovirus (CMV) and the BK virus (BKV) increases. Herein, we present a case where high-dose intravenous immunoglobulin (IVIG) was effective in treating viral infections after transplantation.

METHODS

A 41-year-old man underwent an ABOi transplantation. The initial isoagglutinin titer was 1:32. The patient received 200 mg of rituximab, and 3 rounds of plasmapheresis were performed. Subsequently, renal function remained normal; however, 7 months later, the renal function declined, and BK nephropathy and CMV infection were diagnosed through biopsy and serologic tests. The FK level was reduced, and mycophenolate mofetil was discontinued. Although ciprofloxacin and leflunomide were administered, their effects were minimal. Therefore, high-dose IVIG (1 g/kg) was administered 5 times over 5 weeks, which led to a reduction in BK viral load and CMV infectivity in the serum.

CONCLUSIONS

High-dose IVIG may serve as a promising alternative treatment to mitigate early transplant rejection and BKV and CMV infections.

Solid organ transplantation and gut microbiota: a review of the potential immunomodulatory properties of short-chain fatty acids in graft maintenance

Transplantation is the treatment of choice for several end-stage organ defects: it considerably improves patient survival and quality of life. However, post-transplant recipients may experience episodes of rejection that can favor or ultimately lead to graft loss. Graft maintenance requires a complex and life-long immunosuppressive treatment. Different immunosuppressive drugs (i.e., calcineurin inhibitors, glucocorticoids, biological immunosuppressive agents, mammalian target of rapamycin inhibitors, and antiproliferative or antimetabolic agents) are used in combination to mitigate the immune response against the allograft. Unfortunately, the use of these antirejection agents may lead to opportunistic infections, metabolic (e.g., post-transplant diabetes mellitus) or cardiovascular (e.g., arterial hypertension) disorders, cancer (e.g., non-Hodgkin lymphoma) and other adverse effects. Lately, immunosuppressive drugs have also been associated with gut microbiome alterations, known as dysbiosis, and were shown to affect gut microbiota-derived short-chain fatty acids (SCFA) production. SCFA play a key immunomodulatory role in physiological conditions, and their impairment in transplant patients could partly counterbalance the effect of immunosuppressive drugs leading to the activation of deleterious pathways and graft rejection. In this review, we will first present an overview of the mechanisms of graft rejection that are prevented by the immunosuppressive protocol. Next, we will explain the dynamic changes of the gut microbiota during transplantation, focusing on SCFA. Finally, we will describe the known functions of SCFA in regulating immune-inflammatory reactions and discuss the impact of SCFA impairment in immunosuppressive drug treated patients.

Frequency and impact on renal transplant outcomes of urinary tract infections due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species

Background

Enterobacterales are often responsible for urinary tract infection (UTI) in kidney transplant recipients. Among these, Escherichia coli or Klebsiella species producing extended-spectrum beta-lactamase (ESBL) are emerging. However, there are only scarce data on frequency and impact of ESBL-UTI on transplant outcomes.

Methods

We investigated frequency and impact of first-year UTI events with ESBL Escherichia coli and/or Klebsiella species in a prospective multicenter cohort consisting of 1,482 kidney transplants performed between 2012 and 2017, focusing only on 389 kidney transplants having at least one UTI with Escherichia coli and/or Klebsiella species. The cohort had a median follow-up of four years.

Results

In total, 139/825 (17%) first-year UTI events in 69/389 (18%) transplant recipients were caused by ESBL-producing strains. Both UTI phenotypes and proportion among all UTI events over time were not different compared with UTI caused by non-ESBL-producing strains. However, hospitalizations in UTI with ESBL-producing strains were more often observed (39% versus 26%, p = 0.04). Transplant recipients with first-year UTI events with an ESBL-producing strain had more frequently recurrent UTI (33% versus 18%, p = 0.02) but there was no significant difference in one-year kidney function as well as longer-term graft and patient survival between patients with and without ESBL-UTI.

Conclusion

First-year UTI events with ESBL-producing Escherichia coli and/or Klebsiella species are associated with a higher need for hospitalization but do neither impact allograft function nor allograft and patient survival.

Profile, Risk Factors, and Outcomes of Asymptomatic Bacteriuria in Kidney Transplant Recipients with Normal Pretransplant Genitourinary Tract: A Single-Center Experience

Introduction

There is a paucity of studies on asymptomatic bacteriuria (ASB) among kidney transplant recipients (KTR) in developing countries. This study assessed the clinical profile, risk factors, outcomes, and impact of treatment of ASB in KTRs with a normal genitourinary tract.

Methods

Consecutive KTRs from 2009 to 2018 with no clinical or radiological evidence of obstructive uropathy were included. Urinary tract infection (UTI) after ASB was defined as occurrence of cystitis, pyelonephritis, or urosepsis, with ASB being the first bacteriuric episode.

Results

Seven hundred ten out of 794 patients with median follow up of 47 months were included. The mean age was 35.5 ± 12 years. Eighty-one patients (11.4%) developed ASB at a median of 25 days (IQR 10, 134.5). Fifty-three percent and 4.9% of ASB episodes were extended-spectrum beta-lactamase (ESBL) positive and carbapenem-resistant organisms, respectively. Eighteen patients (32.1%) with early ASB (<3 months) and 5 (20%) with late ASB developed UTI on follow-up. Fifty-five percent of early and 16% of late ASB episodes were treated, with no significant difference observed in the risk of development of UTI when compared to untreated ASB episodes.

Conclusion

The incidence of ASB as first bacteriuric episode in our cohort was 11.4%, with there being significant antimicrobial resistance. Female gender, pretransplant UTI, and delayed graft function were independently associated with development of ASB. Treatment of ASB episodes either early or late did not decrease the risk of development of UTI.

Hematopoietic cell-based and non-hematopoietic cell-based strategies for immune tolerance induction in living-donor renal transplantation: A systematic review

INTRODUCTION

Despite its use to prevent acute rejection, lifelong immunosuppression can adversely impact long-term patient and graft outcomes. In theory, immunosuppression withdrawal is the ultimate goal of kidney transplantation, and is made possible by the induction of immunological tolerance. The purpose of this paper is to review the safety and efficacy of immune tolerance induction strategies in living-donor kidney transplantation, both chimerism-based and non-chimerism-based. The impact of these strategies on transplant outcomes, including acute rejection, allograft function and survival, cost, and immune monitoring, will also be discussed.

MATERIALS AND METHODS

Databases such as PubMed, Scopus, and Web of Science, as well as additional online resources such as EBSCO, were exhaustively searched. Adult living-donor kidney transplant recipients who developed chimerism-based tolerance after concurrent bone marrow or hematopoietic stem cell transplantation or those who received non-chimerism-based, non-hematopoietic cell therapy using mesenchymal stromal cells, dendritic cells, or regulatory T cells were studied between 2000 and 2021. Individual sources of evidence were evaluated critically, and the strength of evidence and risk of bias for each outcome of the transplant tolerance study were assessed.

RESULTS

From 28,173 citations, 245 studies were retrieved after suitable exclusion and duplicate removal. Of these, 22 studies (2 RCTs, 11 cohort studies, 6 case-control studies, and 3 case reports) explicitly related to both interventions (chimerism- and non-chimerism-based immune tolerance) were used in the final review process and were critically appraised. According to the findings, chimerism-based strategies fostered immunotolerance, allowing for the safe withdrawal of immunosuppressive medications. Cell-based therapy, on the other hand, frequently did not induce tolerance except for minimising immunosuppression. As a result, the rejection rates, renal allograft function, and survival rates could not be directly compared between these two groups. While chimerism-based tolerance protocols posed safety concerns due to myelosuppression, including infections and graft-versus-host disease, cell-based strategies lacked these adverse effects and were largely safe. There was a lack of direct comparisons between HLA-identical and HLA-disparate recipients, and the cost implications were not examined in several of the retrieved studies. Most studies reported successful immunosuppressive weaning lasting at least 3 years (ranging up to 11.4 years in some studies), particularly with chimerism-based therapy, while only a few investigators used immune surveillance techniques. The studies reviewed were often limited by selection, classification, ascertainment, performance, and attrition bias.

CONCLUSIONS

This review demonstrates that chimerism-based hematopoietic strategies induce immune tolerance, and a substantial number of patients are successfully weaned off immunosuppression. Despite the risk of complications associated with myelosuppression. Non-chimerism-based, non-hematopoietic cell protocols, on the other hand, have been proven to facilitate immunosuppression minimization but seldom elicit immunological tolerance. However, the results of this review must be interpreted with caution because of the non-randomised study design, potential confounding, and small sample size of the included studies. Further validation and refinement of tolerogenic protocols in accordance with local practice preferences is also warranted, with an emphasis on patient selection, cost ramifications, and immunological surveillance based on reliable tolerance assays.

Brain abscess following kidney transplantation: A single centre observational study from North India

Background

Amongst the infections in kidney transplant recipients, brain abscess represents an uncommon life-threatening complication. Mortality continues to be high despite improvements in diagnostics and therapeutics.

Method

We conducted an observational study, describing the incidence, presentation, implicating pathogen, management and outcome of brain abscess following kidney transplantation at our centre.

Result

Amongst the 1492 patients who underwent kidney transplantation at our centre between June 1991 and January 2023 (cumulative follow-up: 4936 patient-years), five females and four males, developed brain abscesses. The incidence proportion (risk) is 0.6% with an incidence rate of 6.03 cases per 1000 patient years. The median duration from transplant to development of brain abscess was 5 weeks (range: 4 weeks to 9 years). The commonest presentation was a headache. A definitive microbiological diagnosis was established in eight out of nine patients. The commonest implicated organism was a dematiaceous fungus, Cladophialophora bantiana (3 patients, 33.3%). Despite the reduction in immunosuppression, surgical evacuation and optimal medical therapy, five (55.55%) patients succumbed to their illness.

Conclusions

Brain abscesses following kidney transplantation is an uncommon, life-threatening condition. It usually occurs in the early post-transplant period and the presentation is often subtle. Unlike immunocompetent individuals, a fungus is the most common causative organism in those with solid organ transplants. The management includes a reduction in immunosuppression, early antimicrobial therapy, and surgical decompression.

Hypoalbuminemia is a risk factor for invasive fungal infections and poor outcomes in infected kidney transplant recipients

INTRODUCTION

Invasive fungal infections (IFI), are estimated to occur in 2%-14% of kidney transplant recipients (KTRs) in the current era of immune suppression and are associated with high mortality rates. We hypothesized that hypoalbuminemia in KTRs is a risk factor for IFI and would be associated with poor outcomes.

METHODS

In this study, using data from a prospective cohort registry, we describe the frequency of IFI due to Blastomycosis, Coccidioidomycosis, Histoplasmosis, Aspergillosis, and Cryptococcus in KTRs with serum albumin levels measured 3-6 months before diagnosis. Controls were selected based on incidence density sampling. KTRs were divided into three groups based on the pre-IFI serum albumin level: normal (≥4 g/dL), mild (3-4 g/dL), or severe (<3 g/dL) hypoalbuminemia. Outcomes of interest were uncensored graft failure after IFI and overall mortality.

RESULTS

A total of 113 KTRs with IFI were compared with 348 controls. The incidence rate of IFI among individuals with normal, mild, and severe hypoalbuminemia was 3.6, 8.7, and 29.3 per 100 person-years, respectively. After adjustment for multiple variables, the trend for risk of uncensored graft failure following IFI was greater in KTRS with mild (HR = 2.1; 95% CI, .75-6.1) and severe (HR = 4.47; 95% CI, 1.56-12.8) hypoalbuminemia (P-trend < .001) compared to those with normal serum albumin. Similarly, mortality was higher in severe hypoalbuminemia (HR = 1.9; 95% CI, .67-5.6) compared to normal serum albumin (P-trend < .001).

CONCLUSION

Hypoalbuminemia precedes the diagnosis of IFI in KTRs, and is associated with poor outcomes following IFI. Hypoalbuminemia may be a useful predictor of IFI in KTRs and could be incorporated into screening algorithms.

Human polyomavirus 9 as a potential threat in kidney transplant recipients; lessons from BKPyV

As a therapeutic method, kidney transplantation significantly improved the life quality and prognosis of patients with the end-stage renal disease. Since a key element in stable kidney transplantation is continuous therapy with immunosuppressive agents, an inhibited immune response makes patients vulnerable to opportunistic viral and bacterial infections. Polyomavirus (PyV), from the Polyomaviridae family, includes a well-known BK virus (BKPyV) and less publicized human polyomavirus 9 (HPyV9). Both these viruses may inflict significant damage to kidney transplants because of their high prevalence and pathogenesis. While a great body of knowledge was accumulated about the BKPyV-caused nephropathy, much less information is about the potential threat from the HPyV9-caused damage to kidney transplants. The current review provides a glimpse of general information about the PyV-associated nephropathy with a special focus on the role of the HPyV9 in pathogenesis of nephropathy in kidney transplants.

Coronavirus disease 2019 in kidney transplant recipients: a systematic review and meta-analysis

Introduction

The clinical presentation and outcomes of coronavirus disease 2019 (COVID-19) in kidney transplant recipients (KTRs) have not been well studied.

Methods

We performed a meta-analysis to examine the presenting features, outcomes and the effect of treatment on outcomes of KTRs with COVID-19. Database search was performed up to 5 September 2020 through PubMed, Embase, Web of Science, Scopus and CENTRAL.

Results

Overall, 23 studies (1,373 patients) were included in the review and meta-analysis. The most common presenting symptoms included fever (74.0%, 95% confidence interval [CI] 65.3-81.1), cough (63.3%, 95% CI 56.5-69.6) and dyspnoea (47.5%, 95% CI 39.6-55.6). Pooled rates of mortality and critical illness were 21.1% (95% CI 15.3-28.4) and 27.7% (95% CI 21.5-34.8), respectively. Acute kidney injury occurred in 38.9% (95% CI 30.6-48.1) and dialysis was required in 12.4% (95% CI 8.3-18.0) of the cases.

Conclusion

Kidney transplant recipients with COVID-19 have a similar clinical presentation as the general population, but they have higher morbidity and mortality. It is uncertain whether high-dose corticosteroid or hydroxychloroquine reduces the risks of mortality in KTRs with COVID-19.

Prevalence and risk factors of urinary tract infection in kidney recipients: a meta-analysis study

BACKGROUND

A kidney recipient's urinary tract infection (UTI) can result in infectious problems and be a risk factor for less successful transplant outcomes. UTI risk factors are still controversial. The present study aimed to investigate the prevalence of UTI and its association with risk factors in kidney recipients.

METHOD

Twenty-six papers published between 2005 and 2022 were retrieved using keywords and searching Medlib, ScienceDirect, PubMed, and other databases. If possible, the pooled prevalence of UTI in kidney recipients and odds ratio (OR) with a 95% confidence interval for each risk factor were calculated. The data were analyzed using the random effects model in R and Stata 14.

RESULTS

The total sample size was 72,600, with an average age of 48.7 years. The pooled prevalence of UTI was 35% (95% CI, 30-40%). The estimated risk factors for UTI were female (OR = 3.13; 95%CI: 2.35-4.17), older age (OR = 1.03; 95%CI: 1-1.05), history of UTI (OR = 1.31; 95%CI) CI: 1.05-1.63), receiving a kidney from a deceased donor (OR = 1.59; 95%CI: 1.23-2.35), long-term use of an indwelling catheter (OR = 3.03; 95%CI: 1.59-6.59), a ureteral stent (OR = 1.54; 95%CI: 1.16-2.06), diabetes (OR = 1.17; 95%CI: 0.97-1.41), hypertension (OR = 1.6; 95%CI: 1.26-2.28), acute rejection process (OR = 2.22; 95%CI: 1.45-3.4), and abnormal urinary tract anatomy (OR = 2.87; 95%CI 1.44-5.74).

CONCLUSION

This meta-analysis revealed that UTIs are a significant problem in kidney recipients. Factors such as female sex, old age, history of UTIs, deceased donor, long-term use of an indwelling catheter, diabetes, acute rejection process, use of ureteral stent, abnormal urinary tract anatomy, and hypertension were related to an increased risk of UTIs in kidney recipients.

Tuberculosis in Kidney Transplant Recipients: A Nationwide Cohort in a Low Tuberculosis Incidence Country

Background

World Health Organization recommends tuberculosis (TB) preventive treatment for risk groups such as patients preparing for organ transplantation. Pretransplant screening or treatment of latent TB infection has not been routine practice in Finland.

Methods

In this nationwide registry study, we assessed the risk of TB among kidney transplant recipients compared to the general population. TB cases were identified by data linkage of the national infectious disease and the national transplant registries between 1995 and 2019. Standardized incidence ratios were calculated with adjustment for age, sex, and annual TB dynamics.

Results

A total of 4101 kidney transplants in 3900 recipients with a follow-up of 37 652 patient-years were included. Eighteen TB cases were detected. Patients diagnosed with TB were older (median age 64 y, interquartile range 56-66) at transplantation than those without TB (median 51 y, interquartile range 41-60, P < 0.001). The standardized incidence ratio of TB was 6.9 among kidney transplant recipients compared to general population during the whole study period 1995-2019 but decreased from 12.5 in 1995-2007 to 3.2 in 2008-2019. The standardized incidence ratio was 44.2 during the first year after transplantation. Significant differences in 5-y graft losses were not detected between TB patients and those without TB.

Conclusions

The standardized incidence ratio of TB in kidney transplant recipients has decreased over the years, but these patients remain at risk of TB, especially during the first posttransplant year. Cost-benefit analysis is required to address feasibility of latent TB infection screening among transplant candidates in countries with low incidence of TB.

Diagnosis, Prevention, and Treatment of Infections in Kidney Transplantation

Kidney transplant often is complicated by infections in the recipient from therapy-related and patient-related risk factors. Infections in kidney transplant recipients are associated with increased morbidity, mortality, and allograft dysfunction. There is a predictable timeline after kidney transplant regarding the types of pathogens causing infections, reflecting the net state of immunosuppression. In the early post-transplant period, bacterial infections comprise two thirds of all infections, followed by viral and fungal infections. Infections occurring early after kidney transplantation are generally the result of postoperative complications. In most cases, opportunistic infections occur within 6 months after kidney transplantation. They may be caused by a new infection, a donor-derived infection, or reactivation of a latent infection. Community-acquired pneumonia, upper respiratory tract infections, urinary tract infections, and gastrointestinal infections are the most common infections in the late period after transplantation when the net immunosuppression is minimal. It is crucial to seek information on the time after transplant, reflecting the net state of immunosuppression, previous history of exposure/infections, geography, and seasonal outbreaks. It is imperative that we develop regionally specific guidelines on screening, prevention, and management of infections after kidney transplantation.

Early versus late removal of urinary catheter after kidney transplantation

BACKGROUND

The optimal treatment for end-stage kidney disease is kidney transplantation. During the operation, a catheter is introduced into the bladder and remains in place postoperatively to allow the bladder to drain. This decreases tension from the cysto-ureteric anastomosis and promotes healing. Unfortunately, urinary catheters can pose an infection risk to patients as they allow bacteria into the bladder, potentially resulting in a urinary tract infection (UTI). The longer the catheter remains in place, the greater the risk of developing a UTI. There is no consensus approach to the time a catheter should remain in place post-transplant. Furthermore, the different timings of catheter removal are thought to be associated with different incidences of UTI and postoperative complications, such as anastomotic breakdown.

OBJECTIVES

This review aimed to compare patients who had their catheter removed < 5 days post-transplant surgery to those patients who had their catheter removed ≥ 5 days following their kidney transplant. Primary outcome measures between the two groups included: the incidence of symptomatic UTIs, the incidence of asymptomatic bacteriuria and the incidence of major urological complications requiring intervention and treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 April 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs comparing timing of catheter removal post-transplantation were eligible for inclusion. All donor types were included, and all recipients were included regardless of age, demographics or type of urinary catheter used.

DATA COLLECTION AND ANALYSIS

Results from the literature search were screened by two authors to identify if they met our inclusion criteria. We designated removal of a urinary catheter before five days (120 hours) as an 'early removal' and anything later than this as a 'late removal.' The studies were assessed for quality using the risk of bias tool. The primary outcome of interest was the incidence of asymptomatic bacteriuria. Statistical analyses were performed using the random effects model, and results were expressed as relative risk (RR) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Two studies (197 patients) were included in our analysis. One study comprised a full-text article, and the other was a conference abstract with very limited information. The risk of bias in the included studies was generally either high or unclear. It is uncertain whether early versus late removal of the urinary catheter made any difference to the incidence of asymptomatic bacteriuria (RR 0.89, 95% Cl 0.17 to 4.57; participants = 197; I2 = 88%; very low certainty evidence). Data on other outcomes, such as the incidence of UTI and the incidence of major urological complications, were lacking. Furthermore, the follow-up of patients across the studies was short, with no patients being followed beyond one month.

AUTHORS' CONCLUSIONS

A high-quality, well-designed RCT is required to compare the effectiveness of early catheter removal versus late catheter removal in patients following a kidney transplant. At the present time, there is insufficient evidence to suggest any difference between early and late catheter removal post-transplant, and the studies investigating this were generally of poor quality.

Role of Fine Needle Aspiration Cytology in the Rapid Diagnosis of Pulmonary Infections in Renal Allograft Recipients with Respiratory Failure

Background

Renal transplantation is the treatment of choice in patients with end-stage renal disease. However, allograft recipients are at a higher risk of infection due to immunosuppressive therapies. This study aimed to analyze the utility of fine needle aspiration cytology (FNAC) lung in the etiological diagnosis of pulmonary infections in renal allograft recipients with respiratory failure.

Materials and Methods

This is a retrospective study done in post-renal transplant patients presenting with pulmonary infections and respiratory failure in the past 7 years, in whom image-guided lung FNAC was done for diagnosis.

Results

A total of 35 renal allograft recipients presenting with respiratory failure and having focal or diffuse pulmonary opacities (lesions) on radiological imaging were subjected to lung FNAC. The mean age of the patients was 41.1 ± 11.8 years (range 19-72), with the majority being males (n = 28, 80%); six (17.1%) of them were on invasive ventilation. The diagnostic yield of FNAC in our cohort was 77.1% (27 out of 35). Microorganisms were isolated in 21 cases (60%), with Nocardia being the most common (nine cases, 25.7%), Mycobacterial tuberculosis identified in six patients (17.1%), Aspergillus in three (8.6%), and one (2.9%) each had atypical Mycobacterium, zygomycetes, and Cryptococcus. FNAC suggested viral cytopathic effect in five patients, and cytomegalovirus (CMV) quantitative polymerase chain reaction test was found positive in four of these. One case was diagnosed as adenocarcinoma lung.

Conclusion

Lung FNAC is a useful for establishing the etiological diagnosis of pulmonary lesions in renal transplant patients with respiratory failure.

Prevalence and clinical risk factors for esophageal candidiasis in non-human immunodeficiency virus patients: A multicenter retrospective case-control study

BACKGROUND

Although esophageal candidiasis (EC) may manifest in immunocompetent individuals, there is a lack of consensus in the current literature about predisposing conditions that increase the risk of infection.

AIM

To determine the prevalence of EC in patients without human immunodeficiency virus (HIV) and identify risk factors for infection.

METHODS

We retrospectively reviewed inpatient and outpatient encounters from 5 regional hospitals within the United States (US) from 2015 to 2020. International Classification of Diseases, Ninth and Tenth Revisions were used to identify patients with endoscopic biopsies of the esophagus and EC. Patients with HIV were excluded. Adults with EC were compared to age, gender, and encounter-matched controls without EC. Patient demographics, symptoms, diagnoses, medications, and laboratory data were obtained from chart extraction. Differences in medians for continuous variables were compared using the Kruskal-Wallis test and categorical variables using chi-square analyses. Multivariable logistic regression was used to identify independent risk factors for EC, after adjusting for potential confounding factors.

RESULTS

Of the 1969 patients who had endoscopic biopsies of the esophagus performed from 2015 to 2020, 295 patients had the diagnosis of EC. 177 of 1969 patients (8.99%) had pathology confirming the diagnosis of EC and were included in the study for data collection and further analysis. In comparison to controls, patients with EC had significantly higher rates of gastroesophageal reflux disease (40.10% vs 27.50%; P = 0.006), prior organ transplant (10.70% vs 2%; P < 0.001), immunosuppressive medication (18.10% vs 8.10%; P = 0.002), proton pump inhibitor (48% vs 30%; P < 0.001), corticosteroid (35% vs 17%; P < 0.001), Tylenol (25.40% vs 16.20%; P = 0.019), and aspirin use (39% vs 27.50%; P = 0.013). On multivariable logistic regression analysis, patients with a prior organ transplant had increased odds of EC (OR = 5.81; P = 0.009), as did patients taking a proton pump inhibitor (OR = 1.66; P = 0.03) or corticosteroids (OR = 2.05; P = 0.007). Patients with gastroesophageal reflux disease or medication use, including immunosuppressive medications, Tylenol, and aspirin, did not have a significantly increased odds of EC.

CONCLUSION

Prevalence of EC in non-HIV patients was approximately 9% in the US from 2015-2020. Prior organ transplant, proton pump inhibitors, and corticosteroids were identified as independent risk factors for EC.

Regulation of gut microbiota: a novel pretreatment for complications in patients who have undergone kidney transplantation

Kidney transplantation is an effective method to improve the condition of patients with end-stage renal disease. The gut microbiota significantly affects the immune system and can be used as an influencing factor to change the prognoses of patients who have undergone kidney transplantation. Recipients after kidney transplantation showed a lower abundance of Firmicutes and Faecalibacterium prausnitzii and a higher proportion of Bacteroidetes and Proteobacteria. After using prebiotics, synbiotics, and fecal microbiota transplantation to regulate the microbial community, the prognoses of patients who underwent kidney transplantation evidently improved. We aimed to determine the relationship between gut microbiota and various postoperative complications inpatients who have undergone kidney transplantation in recent years and to explore how gut microecology affects post-transplant complications. An in-depth understanding of the specific functions of gut microbiota and identification of the actual pathogenic flora during complications in patients undergoing kidney transplantation can help physicians develop strategies to restore the normal intestinal microbiome of transplant patients to maximize their survival and improve their quality of life.

External ureteric stent versus internal double J stent in kidney transplantation: a retrospective analysis on the incidence of urological complications and urinary tract infections

Introduction

Urologic complications (UCs) and urinary tract infections (UTIs) are common after kidney transplantation. Intraoperative stent placement at the vesicoureteric anastomosis reduces UC risk, but increases UTI risk.

Methods

In 2014 our stenting protocol changed from external ureteric stent (ES) to internal double J stent (DJ). We retrospectively studied the occurrence of UCs and UTIs in relation to ES or DJ in 697 kidney recipients.

Methods

An ES was used in 403 patients (57.8%), in 294 (42.2%) a DJ. ES was removed 7-12 days and DJ 3-4 weeks post-operative. Induction immunosuppression was the same in both groups. Primary outcomes at 6 months follow-up were UC (urinary leakage/ureter stenosis) and UTI; they were related to stenting procedure and clinical and transplant characteristics. The incidence of UCs was similar for ES (8.4%) and DJ (6.8%), p=0.389. ES use was a significant risk factor for UTI (OR 1.69 (1.15-2.50), p=0.008). Post-transplant hospitalization was significantly shorter in the DJ group. Despite more acute rejection episodes with ES (ES/DJ: 16.4%/6.1%, p<0.001), no clinical relevant differences in graft outcomes existed.

Discussion

A DJ is, compared to ES, associated with a lower incidence of UTIs and comparable occurrence of UCs and is therefore the preferred technique for stenting the vesicoureteric anastomosis.

Machine learning does not outperform traditional statistical modelling for kidney allograft failure prediction

Machine learning (ML) models have recently shown potential for predicting kidney allograft outcomes. However, their ability to outperform traditional approaches remains poorly investigated. Therefore, using large cohorts of kidney transplant recipients from 14 centers worldwide, we developed ML-based prediction models for kidney allograft survival and compared their prediction performances to those achieved by a validated Cox-Based Prognostication System (CBPS). In a French derivation cohort of 4000 patients, candidate determinants of allograft failure including donor, recipient and transplant-related parameters were used as predictors to develop tree-based models (RSF, RSF-ERT, CIF), Support Vector Machine models (LK-SVM, AK-SVM) and a gradient boosting model (XGBoost). Models were externally validated with cohorts of 2214 patients from Europe, 1537 from North America, and 671 from South America. Among these 8422 kidney transplant recipients, 1081 (12.84%) lost their grafts after a median post-transplant follow-up time of 6.25 years (Inter Quartile Range 4.33-8.73). At seven years post-risk evaluation, the ML models achieved a C-index of 0.788 (95% bootstrap percentile confidence interval 0.736-0.833), 0.779 (0.724-0.825), 0.786 (0.735-0.832), 0.527 (0.456-0.602), 0.704 (0.648-0.759) and 0.767 (0.711-0.815) for RSF, RSF-ERT, CIF, LK-SVM, AK-SVM and XGBoost respectively, compared with 0.808 (0.792-0.829) for the CBPS. In validation cohorts, ML models' discrimination performances were in a similar range of those of the CBPS. Calibrations of the ML models were similar or less accurate than those of the CBPS. Thus, when using a transparent methodological pipeline in validated international cohorts, ML models, despite overall good performances, do not outperform a traditional CBPS in predicting kidney allograft failure. Hence, our current study supports the continued use of traditional statistical approaches for kidney graft prognostication.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

Chemoprophylaxis for the prevention of tuberculosis in kidney transplant recipients: A systematic review and meta-analysis

Background: A systematic review and meta-analysis was performed to investigate the efficacy and safety of isoniazid (INH) prophylaxis to prevent tuberculosis (TB) infection in kidney transplant recipients (KTRs).

Methods: Web of Science, SCOPUS, and PubMed were searched to identify relevant studies that compared the effects among patients who received INH prophylaxis after transplantation.

Results: A total of 13 studies (involving 6,547 KTRs) were included in our analysis. We found that the risk of active TB infection (RR: 0.35, 95%CI 0.27–0.45, p &lt; 0.01) for KTRs was lower in the INH treatment group than in those without prophylaxis. However, there was no significant difference between the two groups in mortality (RR: 0.93, 95%CI 0.67–1.28, p = 0.64), acute rejection (RR: 0.82, 95%CI 0.44–1.51, p = 0.52), and hepatotoxicity (RR: 1.25, 95%CI 0.94–1.65, p = 0.12).

Conclusion: Isoniazid prophylaxis is a safe and effective for KTRs on reactivation of latent TB infection.

Extracellular Vesicles: The Future of Diagnosis in Solid Organ Transplantation?

Solid organ transplantation (SOT) is a life-saving treatment for end-stage organ failure, but it comes with several challenges, the most important of which is the existing gap between the need for transplants and organ availability. One of the main concerns in this regard is the lack of accurate non-invasive biomarkers to monitor the status of a transplanted organ. Extracellular vesicles (EVs) have recently emerged as a promising source of biomarkers for various diseases. In the context of SOT, EVs have been shown to be involved in the communication between donor and recipient cells and may carry valuable information about the function of an allograft. This has led to an increasing interest in exploring the use of EVs for the preoperative assessment of organs, early postoperative monitoring of graft function, or the diagnosis of rejection, infection, ischemia-reperfusion injury, or drug toxicity. In this review, we summarize recent evidence on the use of EVs as biomarkers for these conditions and discuss their applicability in the clinical setting.

Predictor factor for worse outcomes in kidney transplant recipients infected with coronavirus disease 2019: A systematic review and meta-analysis

INTRODUCTION

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a massive impact on the health sector, especially in patients with pre-existing comorbidities. This study aims to define the predictor factors for worse outcomes in kidney transplant patients infected with SARS-CoV-2 and affected by coronavirus disease 2019 (COVID-19). We have analyzed in these patients their prior medical history, their clinical symptoms, and their laboratory results.

METHOD

We assessed outcomes of kidney transplant patients with confirmed COVID-19 until July 2021 from PubMed, Medline, Science Direct, Cochrane databases, EMBASE, Scopus, and EBSCO. We performed meta-analyses of nine published studies to estimate predictor factors. The analysis was analyzed by the Newcastle-Ottawa Scale (NOS) and then using the Review Manager 5.4 software.

RESULT

Our analysis demonstrated that the most significant risk factors for the worse COVID-19 outcomes for kidney transplant patients included: age of 60 and older [MD 9.31(95% CI, 6.31-12.30), p < 0.0001, I2 = 76%], diabetic nephropathy [OR 2.13 (95% CI, 1.49-3.04), p < 0.0001, I2 = 76%], dyspnea [OR 4.53, (95% CI, 2.22-9.22), p < 0.0001, I2 = 76%], acute kidney injury (AKI) [OR 4.53 (95% CI, 1.10-5.21), p = 0.03, I2 = 58%], and some laboratory markers. Many patients had two or multiple risk factors in combination.

CONCLUSION

Age and several comorbidities were the most significant factors for COVID-19 outcomes for kidney transplant recipients.

A GMP Protocol for the Manufacture of Tregs for Clinical Application

Infusion of regulatory T cells is a promising therapeutic strategy in organ transplantation to modulate the immune system, prevent rejection, minimize the need for pharmaceutical immunosuppression, and improve long-term transplant outcomes. Here we describe a GMP-compliant method we have used for the manufacture of ex vivo expanded autologous regulatory T cells for use in clinical trials.

Comparison of artificial intelligence and human-based prediction and stratification of the risk of long-term kidney allograft failure

BACKGROUND

Clinical decisions are mainly driven by the ability of physicians to apply risk stratification to patients. However, this task is difficult as it requires complex integration of numerous parameters and is impacted by patient heterogeneity. We sought to evaluate the ability of transplant physicians to predict the risk of long-term allograft failure and compare them to a validated artificial intelligence (AI) prediction algorithm.

METHODS

We randomly selected 400 kidney transplant recipients from a qualified dataset of 4000 patients. For each patient, 44 features routinely collected during the first-year post-transplant were compiled in an electronic health record (EHR). We enrolled 9 transplant physicians at various career stages. At 1-year post-transplant, they blindly predicted the long-term graft survival with probabilities for each patient. Their predictions were compared with those of a validated prediction system (iBox). We assessed the determinants of each physician's prediction using a random forest survival model.

RESULTS

Among the 400 patients included, 84 graft failures occurred at 7 years post-evaluation. The iBox system demonstrates the best predictive performance with a discrimination of 0.79 and a median calibration error of 5.79%, while physicians tend to overestimate the risk of graft failure. Physicians' risk predictions show wide heterogeneity with a moderate intraclass correlation of 0.58. The determinants of physicians' prediction are disparate, with poor agreement regardless of their clinical experience.

CONCLUSIONS

This study shows the overall limited performance and consistency of physicians to predict the risk of long-term graft failure, demonstrated by the superior performances of the iBox. This study supports the use of a companion tool to help physicians in their prognostic judgement and decision-making in clinical care.

Bacterial Urinary Tract Infection and Early Asymptomatic Bacteriuria in Kidney Transplantation Still Negatively Affect Kidney Transplant Outcomes in the Era of Modern Immunosuppression and Cotrimoxazole Prophylaxis

Risk factors and consequences of urinary tract infection (UTI) post-kidney transplant have been variously reported by studies that were heterogenous in immunosuppressants and prophylactic protocols. We aimed to clarify the risks and consequences of UTI in kidney transplant recipients with post-transplantation cotrimoxazole prophylaxis in the context of modern immunosuppression. This retrospective cohort included kidney transplant recipients receiving tacrolimus, mycophenolate, prednisolone, and cotrimoxazole for bacterial UTI prophylaxis. Recipients were categorized into non-UTI and UTI groups. Asymptomatic bacteriuria (ASB) was screened in the first 3 months and was evaluated for association with UTI. Of 348 kidney transplant recipients, 129 were in the UTI group and 219 in the non-UTI group. UTI risk factors were female sex, body mass index ≥ 25 kg/m², human leukocyte antigen mismatch, and panel reactive antibody ≥ 50%. Recipients with recurrent UTI had inferior allograft function compared with non-UTI recipients. Patient survival was significantly lower in recipients with UTI in the first post-transplant month. Higher degree of immunosuppressions was associated with recurrent UTI and drug-resistant organisms. In conclusion, UTI continues to negatively affect graft function and survival of kidney transplant recipients. Treating ASB in the first 3 months did not reduce the UTI incidence in the first transplantation year.

Allograft adenovirus nephritis accompanied by Crohn’s disease in a kidney transplant recipient: a novel case report

Excessive immunosuppression after kidney transplantation (KT) is often encountered in patients undergoing therapy for anti-rejection or autoimmune disease that requires further treatment using immunosuppressive medications (IMs), including biologic agents. We report a novel case wherein a kidney transplant recipient developed severe acute allograft injury and hemorrhagic cystitis at 4.5 years after KT due to adenovirus nephritis after treatment with infliximab for Crohn's disease. The diagnosis was made based on adenovirus immunohistochemistry staining and urine polymerase chain reaction tests. The patient was successfully treated by reducing IMs and administration of immunoglobulin even though allograft function was eventually partially recovered. When new immunosuppressive agents, particularly biologic agents, are initiated for other diseases in addition to maintenance IMs, the following points need to be regarded: (1) pay attention to opportunistic infections even in the late phase of KT, and (2) maintain communication with other specialists who prescribe biologics to ensure appropriate administration of IMs.

Kidney Transplant-Associated Viral Infection Rates and Outcomes in a Single-Centre Cohort

BACKGROUND

Opportunistic infections remain a significant cause of morbidity and mortality after kidney transplantation. This retrospective cohort study aimed to assess the incidence and predictors of post-transplant DNA virus infections (CMV, EBV, BKV and JCV infections) in kidney transplant recipients (KTR) at a single tertiary centre and evaluate their impact on graft outcomes.

METHODS

KTR transplanted between 2000 and 2021 were evaluated. Multivariate logistic regression analysis and Cox proportional hazard analyses were used to identify factors associated with DNA virus infections and their impact on allograft outcomes respectively. A sub-analysis of individual viral infections was also conducted to describe the pattern, timing, interventions, and outcomes of individual infections.

RESULTS

Data from 962 recipients were evaluated (Mean age 47.3 ± 15 years, 62% male, 81% white). 30% of recipients (288/962) had infection(s) by one or more of the DNA viruses. Individually, CMV, EBV, BKV and JCV viruses were diagnosed in 13.8%. 11.3%, 8.9% and 4.4% of recipients respectively. Factors associated with increased risk of post-transplant DNA virus infection included recipient female gender, higher number of HLA mismatch, lower baseline estimated glomerular filtration rate (eGFR), CMV seropositive donor, maintenance with cyclosporin (rather than tacrolimus) and higher number of maintenance immunosuppressive medications. The slope of eGFR decline was steeper in recipients with a history of DNA virus infection irrespective of the virus type. Further, GFR declined faster with an increasing number of different viral infections. Death-censored graft loss adjusted for age, gender, total HLA mismatch, baseline eGFR and acute rejection was significantly higher in recipients with a history of DNA virus infection than those without infection (adjusted hazard ratio (aHR, 1.74, 95% CI, 1.08-2.80)). In contrast, dialysis-free survival did not differ between the two groups of recipients (aHR, 1.13, 95% CI, 0.88-1.47).

CONCLUSION

Post-transplant DNA viral infection is associated with a higher risk of allograft loss. Careful management of immunosuppression and close surveillance of at-risk recipients may improve graft outcomes.

The Association of Organ Preservation Fluid Pathogens with Early Infection-Related Events after Kidney Transplantation

(1) Background: The need to elucidate the microbial patterns in preservation fluid and explore their relationship with early infection-related events post kidney transplant and investigate antimicrobial resistance and the effects of preemptive antibiotic therapy. (2) Methods: This retrospective study analyzed the clinical data of 514 kidney transplant donors and 808 recipients from April 2015 to October 2020. Clinical data of donor and recipient characteristics, preservation fluid microbes, early infections (≤30 days), probable donor-derived infections (P-DDIs), antimicrobial resistance and preemptive antibiotic therapy was collected. (3) Results: The incidence of bloodstream (10.3% versus 5.2%, p = 0.006) and graft-site infections (9.7% versus 4.6%, p = 0.004) was significantly higher in recipients with culture-positive preservation fluid. In addition, recipients with ESKAPE pathogens or Candida species had a notably higher rate of bloodstream infections (14.1% versus 6.9%, p = 0.033) and graft-site infections (16.7% versus 3.5%, p < 0.01) than those with other positive pathogens. Preemptive antibiotic therapy decreased the bloodstream infection rate (11.8% versus 35.7%, p = 0.047) when preservation fluid was positive for ESKAPE pathogens. (4) Conclusions: Culture-positive preservation fluid has potential implications for kidney transplant recipients. ESKAPE pathogens or Candida species in preservation fluid as well as their antimicrobial resistance properties and non-preemptive antibiotic therapy could pose a risk of early infection-related events.

Mycobacterium Tuberculosis Infection after Kidney Transplantation: A Comprehensive Review

Tuberculosis (TB) in kidney transplant (KT) recipients is an important opportunistic infection with higher incidence and prevalence than in the general population and is associated with important morbidity and mortality. We performed an extensive literature review of articles published between 1 January 2000 and 15 June 2022 to provide an evidence-based review of epidemiology, pathogenesis, diagnosis, treatment and outcomes of TB in KT recipients. We included all studies which reported epidemiological and/or outcome data regarding active TB in KT, and we approached the diagnostic and treatment challenges according to the current guidelines. Prevalence of active TB in KT recipients ranges between 0.3–15.2%. KT recipients with active TB could have a rejection rate up to 55.6%, a rate of graft loss that varies from 2.2% to 66.6% and a mortality rate up to 60%. Understanding the epidemiological risk, risk factors, transmission modalities, diagnosis and treatment challenges is critical for clinicians in providing an appropriate management for KT with TB. Among diagnostic challenges, which are at the same time associated with delay in management, the following should be considered: atypical clinical presentation, association with co-infections, decreased predictive values of screening tests, diverse radiological aspects and particular diagnostic methods. Regarding treatment challenges in KT recipients with TB, drug interactions, drug toxicities and therapeutical adherence must be considered.

Rare case of aspergillus brain abscess in an immunocompromised patient

We present a case of aspergillus brain abscess in a 48-year-old woman with a history of kidney transplantation and no underlying central nervous system (CNS) disease. Follow-up of the patient for 4 years shows normal findings. Early diagnosis and aggressive treatment could improve the prognosis of this fatal complication.

A unique case of fever with skin lesions

The incidence of Nocardiosis was c.1-2 per 100,000 population worldwide in the early 2000s. Co-infection with Nocardia and MOTT (mycobacterium other than tuberculosis) is even more uncommon and has been described only in the setting of pulmonary manifestations in an immunocompromised (HIV) patient. However, over the last two decades, the incidence of Nocardiosis has increased to about 7-8 per 100,000 population, with pulmonary manifestations being the most common. With this background, we present the case of a middle-aged immunosuppressed man (post renal transplant with rejection), who presented with fever with extensive skin lesions and features suggestive of sepsis, without pulmonary involvement.

Sepsis affects kidney graft function and one-year mortality of the recipients in contrast with systemic inflammatory response

Background

Infections remain a major cause of morbidity and mortality after kidney transplantation. The aim of our study was to determine the effect of sepsis on kidney graft function and recipient mortality.

Methods

A prospective, observational, single-center study was performed. Selected clinical and biochemical parameters were recorded and compared between an experimental group (with sepsis, n = 34) and a control group (with systemic inflammatory response syndrome, n = 31) comprising kidney allograft recipients.

Results

Sepsis worsened both patient (HR = 14.77, p = 0.007) and graft survival (HR = 15.07, p = 0.007). Overall one-year mortality was associated with age (HR = 1.08, p = 0.048), APACHE II score (HR = 1.13, p = 0.035), and combination immunosuppression therapy (HR = 0.1, p = 0.006), while graft survival was associated with APACHE II (HR = 1.25, p = 0.004) and immunosuppression. In sepsis patients, mortality correlated with the maximal dose of noradrenalin (HR = 100.96, p = 0.008), fungal infection (HR = 5.64, p = 0.024), SAPS II score (HR = 1.06, p = 0.033), and mechanical ventilation (HR = 5.97, p = 0.033), while graft survival was influenced by renal replacement therapy (HR = 21.16, p = 0.005), APACHE II (HR = 1.19, p = 0.035), and duration of mechanical ventilation (HR = 1.01, p = 0.015).

Conclusion

In contrast with systemic inflammatory response syndrome, septic kidney allograft injury is associated with early graft loss and may represent a significant risk of mortality.

Immune responses to SARS-CoV-2 in dialysis and kidney transplantation

Despite progressive improvements in the management of patients with coronavirus disease 2019 (COVID-19), individuals with end-stage kidney disease (ESKD) are still at high risk of infection-related complications. Although the risk of infection in these patients is comparable to that of the general population, their lower rate of response to vaccination is a matter of concern. When prevention strategies fail, infection is often severe. Comorbidities affecting patients on maintenance dialysis and kidney transplant recipients clearly account for the increased risk of severe COVID-19, while the role of uremia and chronic immunosuppression is less clear. Immune monitoring studies have identified differences in the innate and adaptive immune response against the virus that could contribute to the increased disease severity. In particular, individuals on dialysis show signs of T cell exhaustion that may impair antiviral response. Similar to kidney transplant recipients, antibody production in these patients occurs, but with delayed kinetics compared with the general population, leaving them more exposed to viral expansion during the early phases of infection. Overall, unique features of the immune response during COVID-19 in individuals with ESKD may occur with severe comorbidities affecting these individuals in explaining their poor outcomes.

Effects of Bacterial Urinary Tract Infection on Clinical Outcome and Survival of Kidney Transplant Patients

BACKGROUND

There is no consensus on whether the development of urinary tract infections (UTIs) leads to high mortality or graft loss in kidney transplant patients. A high incidence of multidrug resistant (MDR) infections was observed worldwide and is associated with these complications. The aim of this study was to analyze the effects of UTIs on the clinical outcome and survival in kidney transplant patients.

METHODS

This retrospective study evaluated 601 kidney transplant patients who were categorized as follows: group 1 (G1) patients without a UTI, group 2 (G2) patients with a UTI, and group 3 (G3) recipients with a recurrent UTI. Patients were followed up for at least 1 year after transplantation. Graft survival, risk of graft loss, and risk of developing a UTI were analyzed by the Kaplan-Meier method, Cox regression, and logistic regression methods, respectively. Differences with P < .05 were considered statistically significant.

RESULTS

The proportion of rejection episodes was higher in G3 (32.35%) than in G1 (20.89%) and G2 (21.88%) (P < .001). The graft survival after the 10-year follow-up was better in G1 (73.29%) than in G3 (61.62%) (P = .019). UTI recurrent episodes increased the risk of graft loss >2.5-fold. Women and those who received a kidney from a deceased donor (DD) were at risk of at least 1 UTI event during follow-up. A greater proportion of MDR infections was observed in G3 than in G2 (P < .001).

CONCLUSIONS

The risk factors for developing a UTI were female sex, receiving a DD kidney, susceptibility to other infections, episodes of rejection, and delayed graft function. Moreover, a UTI, especially a recurrent UTI, was an important risk factor for allograft loss.

Exploring Porcine Precision-Cut Kidney Slices as a Model for Transplant-Related Ischemia-Reperfusion Injury

Marginal donor kidneys are more likely to develop ischemia-reperfusion injury (IRI), resulting in inferior long-term outcomes. Perfusion techniques are used to attenuate IRI and improve graft quality. However, machine perfusion is still in its infancy, and more research is required for optimal conditions and potential repairing therapies. Experimental machine perfusion using porcine kidneys is a great way to investigate transplant-related IRI, but these experiments are costly and time-consuming. Therefore, an intermediate model to study IRI would be of great value. We developed a precision-cut kidney slice (PCKS) model that resembles ischemia-reperfusion and provides opportunities for studying multiple interventions simultaneously. Porcine kidneys were procured from a local slaughterhouse, exposed to 30 min of warm ischemia, and cold preserved. Subsequently, PCKS were prepared and incubated under various conditions. Adenosine triphosphate (ATP) levels and histological tissue integrity were assessed for renal viability and injury. Slicing did not influence tissue viability, and PCKS remained viable up to 72 h incubation with significantly increased ATP levels. Hypothermic and normothermic incubation led to significantly higher ATP levels than baseline. William’s medium E supplemented with Ciprofloxacin (and Amphotericin-B) provided the most beneficial condition for incubation of porcine PCKS. The porcine PCKS model can be used for studying transplant IRI.

Urinary Tract Infections Caused by K. pneumoniae in Kidney Transplant Recipients – Epidemiology, Virulence and Antibiotic Resistance

Urinary tract infections are the most common complication in kidney transplant recipients, possibly resulting in the deterioration of a long-term kidney allograft function and an increased risk of recipient’s death. K. pneumoniae has emerged as one of the most prevalent etiologic agents in the context of recurrent urinary tract infections, especially with multidrug resistant strains. This paper discusses the epidemiology and risk factors associated with urinary tract infections in kidney transplant recipients, multi-drug resistance of K. pneumoniae (ESBL, KPC, NDM), treatment and pathogenesis of K. pneumoniae infections, and possible causes of recurrent UTIs. It also addresses the issue of colonization/becoming a carrier of K. pneumoniae in the gastrointestinal tract and asymptomatic bacteriuria in relation to a symptomatic UTI development and epidemiology.

Transplantation Without Overimmunosuppression (TWO) study protocol: a phase 2b randomised controlled single-centre trial of regulatory T cell therapy to facilitate immunosuppression reduction in living donor kidney transplant recipients

INTRODUCTION

Regulatory T cell (Treg) therapy has been demonstrated to facilitate long-term allograft survival in preclinical models of transplantation and may permit reduction of immunosuppression and its associated complications in the clinical setting. Phase 1 clinical trials have shown Treg therapy to be safe and feasible in clinical practice. Here we describe a protocol for the TWO study, a phase 2b randomised control trial of Treg therapy in living donor kidney transplant recipients that will confirm safety and explore efficacy of this novel treatment strategy.

METHODS AND ANALYSIS

60 patients will be randomised on a 1:1 basis to Treg therapy (TR001) or standard clinical care (control). Patients in the TR001 arm will receive an infusion of autologous polyclonal ex vivo expanded Tregs 5 days after transplantation instead of standard monoclonal antibody induction. Maintenance immunosuppression will be reduced over the course of the post-transplant period to low-dose tacrolimus monotherapy. Control participants will receive a standard basiliximab-based immunosuppression regimen with long-term tacrolimus and mycophenolate mofetil immunosuppression. The primary endpoint is biopsy proven acute rejection over 18 months; secondary endpoints include immunosuppression burden, chronic graft dysfunction and drug-related complications.

ETHICS AND DISSEMINATION

Ethical approval has been provided by the National Health Service Health Research Authority South Central-Oxford A Research Ethics Committee (reference 18/SC/0054). The study also received authorisation from the UK Medicines and Healthcare products Regulatory Agency and is being run in accordance with the principles of Good Clinical Practice, in collaboration with the registered trials unit Oxford Clinical Trials Research Unit. Results from the TWO study will be published in peer-reviewed scientific/medical journals and presented at scientific/clinical symposia and congresses.

TRIAL REGISTRATION NUMBER

ISRCTN: 11038572; Pre-results.

Bacterial and Viral Infection and Sepsis in Kidney Transplanted Patients

Kidney transplanted patients are a unique population with intrinsic susceptibility to viral and bacterial infections, mainly (but not exclusively) due to continuous immunosuppression. In this setting, infectious episodes remain among the most important causes of death, with different risks according to the degree of immunosuppression, time after transplantation, type of infection, and patient conditions. Prevention, early diagnosis, and appropriate therapy are the goals of infective management, taking into account that some specific characteristics of transplanted patients may cause a delay (the absence of fever or inflammatory symptoms, the negativity of serological tests commonly adopted for the general population, or the atypical anatomical presentation depending on the surgical site and graft implantation). This review considers the recent available findings of the most common viral and bacterial infection in kidney transplanted patients and explores risk factors and outcomes in septic evolution.

Chimerism-Based Tolerance to Kidney Allografts in Humans: Novel Insights and Future Perspectives

Chronic rejection and immunosuppression-related toxicity severely affect long-term outcomes of kidney transplantation. The induction of transplantation tolerance – the lack of destructive immune responses to a transplanted organ in the absence of immunosuppression – could potentially overcome these limitations. Immune tolerance to kidney allografts from living donors has been successfully achieved in humans through clinical protocols based on chimerism induction with hematopoietic cell transplantation after non-myeloablative conditioning. Notably, two of these protocols have led to immune tolerance in a significant fraction of HLA-mismatched donor-recipient combinations, which represent the large majority of cases in clinical practice. Studies in mice and large animals have been critical in dissecting tolerance mechanisms and in selecting the most promising approaches for human translation. However, there are several key differences in tolerance induction between these models and humans, including the rate of success and stability of donor chimerism, as well as the relative contribution of different mechanisms in inducing donor-specific unresponsiveness. Kidney allograft tolerance achieved through durable full-donor chimerism may be due to central deletion of graft-reactive donor T cells, even though mechanistic data from patient series are lacking. On the other hand, immune tolerance attained with transient mixed chimerism-based protocols initially relies on Treg-mediated suppression, followed by peripheral deletion of donor-reactive recipient T-cell clones under antigenic pressure from the graft. These conclusions were supported by data deriving from novel high-throughput T-cell receptor sequencing approaches that allowed tracking of alloreactive repertoires over time. In this review, we summarize the most important mechanistic studies on tolerance induction with combined kidney-bone marrow transplantation in humans, discussing open issues that still need to be addressed and focusing on techniques developed in recent years to efficiently monitor the alloresponse in tolerance trials. These cutting-edge methods will be instrumental for the development of immune tolerance protocols with improved efficacy and to identify patients amenable to safe immunosuppression withdrawal.

Secondary Immunodeficiency Related to Kidney Disease (SIDKD)-Definition, Unmet Need, and Mechanisms

Kidney disease is a known risk factor for poor outcomes of COVID-19 and many other serious infections. Conversely, infection is the second most common cause of death in patients with kidney disease. However, little is known about the underlying secondary immunodeficiency related to kidney disease (SIDKD). In contrast to cardiovascular disease related to kidney disease, which has triggered countless epidemiologic, clinical, and experimental research activities or interventional trials, investments in tracing, understanding, and therapeutically targeting SIDKD have been sparse. As a call for more awareness of SIDKD as an imminent unmet medical need that requires rigorous research activities at all levels, we review the epidemiology of SIDKD and the numerous aspects of the abnormal immunophenotype of patients with kidney disease. We propose a definition of SIDKD and discuss the pathogenic mechanisms of SIDKD known thus far, including more recent insights into the unexpected immunoregulatory roles of elevated levels of FGF23 and hyperuricemia and shifts in the secretome of the intestinal microbiota in kidney disease. As an ultimate goal, we should aim to develop therapeutics that can reduce mortality due to infections in patients with kidney disease by normalizing host defense to pathogens and immune responses to vaccines.

The spatially resolved transcriptional profile of acute T cell-mediated rejection in a kidney allograft

Analysis of the transcriptional profile of graft biopsies represents a promising strategy to study T cell-mediated-rejection (TCMR), also known as acute cellular rejection. However, bulk RNA sequencing of graft biopsies may not capture the focal nature of acute rejection. Herein, we used the whole exome GeoMX Digital Space Profiling platform to study five tubular and three glomerular regions of interest in the kidney graft biopsy from a patient with a chronic-active TCMR episode and in analogous areas from two different normal kidney control biopsies. All kidney sections were from paraffin blocks. Overall, inflammatory genes were significantly upregulated in the tubular areas of the TCMR biopsy and showed an enrichment for gene-ontology terms associated with T-cell activation, differentiation, and proliferation. Enrichment analysis of the 100 genes with the highest coefficient of variation across the TCMR tubular regions of interest revealed that these highly variable genes are involved in kidney development and injury and interestingly do not associate with the 2019 Banff classification pathology scores within the individual regions of interest. Spatial transcriptomics allowed us to unravel a previously unappreciated variability across different areas of the TCMR biopsy related to the graft response to the alloimmune attack, rather than to the immune cells. Thus, our approach has the potential to decipher clinically relevant, new pathogenic mechanisms, and therapeutic targets in acute cellular rejection and other kidney diseases with a focal nature.

Sex and organ-specific risk of major adverse renal or cardiac events in solid organ transplant recipients with COVID-19

While older males are at the highest risk for poor coronavirus disease 2019 (COVID-19) outcomes, it is not known if this applies to the immunosuppressed recipient of a solid organ transplant (SOT), nor how the type of allograft transplanted may impact outcomes. In a cohort study of adult (>18 years) patients testing positive for COVID-19 (January 1, 2020-June 21, 2021) from 56 sites across the United States identified using the National COVID Cohort Collaborative (N3C) Enclave, we used multivariable Cox proportional hazards models to assess time to MARCE after COVID-19 diagnosis in those with and without SOT. We examined the exposure of age-stratified recipient sex overall and separately in kidney, liver, lung, and heart transplant recipients. 3996 (36.4%) SOT and 91 646 (4.8%) non-SOT patients developed MARCE. Risk of post-COVID outcomes differed by transplant allograft type with heart and kidney recipients at highest risk. Males with SOT were at increased risk of MARCE, but to a lesser degree than the non-SOT cohort (HR 0.89, 95% CI 0.81-0.98 for SOT and HR 0.61, 95% CI 0.60-0.62 for non-SOT [females vs. males]). This represents the largest COVID-19 SOT cohort to date and the first-time sex-age-stratified and allograft-specific COVID-19 outcomes have been explored in those with SOT.

Alemtuzumab in Renal Retransplantation - Transplant Outcomes and Associated Infections

Renal retransplant patients have decreased graft survival compared with primary renal transplant patients. Alemtuzumab induction is often used at the time of retransplant; however, the literature surrounding alemtuzumab induction in renal retransplant patients is limited. In this single-center, retrospective, observational study, we aimed to determine the 1-year incidence of infections and transplant outcomes in renal retransplant patients who received alemtuzumab induction. Thirty-four patients who received alemtuzumab met inclusion criteria and were included in the final analysis. Twenty-two (64.7%) of these patients acquired infections. Of these, 7 patients (31.8%) acquired infections that resulted in hospitalization or intravenous antibiotics. The most common infections were urinary tract infections (n = 10; 29.4%), cytomegalovirus DNAemia (n = 7; 20.6%), and BK virus (n = 6; 17.6%). The use of steroid maintenance therapy after alemtuzumab induction did not increase the number of infections compared with patients with a steroid-free interval after alemtuzumab induction. The number of patients who developed de novo donor-specific antibodies (DSA) was 11 (32.4%) with only 1 of these patients having DSA before retransplantation. The incidence of acute cellular rejection was 2.9% (n = 1). There was no graft loss, and patient survival was 97% (n = 33). There were no significant differences in infection rate or DSA development between alemtuzumab and the other induction agents, antithymocyte globulin and basiliximab, among retransplanted patients. Alemtuzumab induction in renal retransplant patients resulted in similar bacterial and viral infection rates as previously reported in the literature and did not negatively impact graft and patient survival.