Organ Transplantation Research Articles

Donor-derived infections in the United States: Opportunities to learn from the Disease Transmission Advisory Committee's experience.

The Disease Transmission Advisory Committee (DTAC) of the Organ Procurement and Transplantation Network focuses on issues related to the transmission of disease through organ transplantation. Providing a review of potential cases of transmission, translating aggregate data into actionable education and guidance for the transplant community, and providing input for policy development, DTAC aims to improve the safety of organ transplantation through a reduction in donor-derived transmission events. Through its nearly 20-year history, DTAC has provided education, guidance, and policy, addressed numerous emerging infections, and continuously focused on the community's understanding of risk assessment related to donor-derived transmission. By updating the DTAC mission to both decrease transmission and safely expand the donor pool with additional guidance to safely use organs previously not considered for transplantation due to transmission concerns, the Committee's role will remain critical.

Burden and Management of Multi-Drug Resistant Organism Infections in Solid Organ Transplant Recipients Across the World: A Narrative Review

Solid organ transplant (SOT) recipients are particularly susceptible to infections caused by multidrug-resistant organisms (MDRO) and are often the first to be affected by an emerging resistant pathogen. Unfortunately, their prevalence and impact on morbidity and mortality according to the type of graft is not systematically reported from high-as well as from low and middle-income countries (HIC and LMIC). Thus, epidemiology on MDRO in SOT recipients could be subjected to reporting bias. In addition, screening practices and diagnostic resources may vary between countries, as well as the availability of new drugs. In this review, we aimed to depict the burden of main Gram-negative MDRO in SOT patients across HIC and LMIC and to provide an overview of current diagnostic and therapeutic resources.

Real-World Experience With Maribavir for Treatment of Cytomegalovirus Infection in High-Risk Solid Organ Transplant Recipients.

We evaluated use of maribavir (MBV) for treatment of 15 episodes of refractory/resistant cytomegalovirus infection in 13 solid organ transplant recipients. Treatment failure due to treatment-emergent MBV resistance or early virological recurrence after MBV discontinuation occurred in 7 (47%) episodes. Sustained viral clearance was achieved in 6 (40%) episodes.

Why partial heart transplantation could be regulated as organ transplantation?

Partial heart transplant (PHT) is a recent clinical innovation involving the transplantation of a segment of the heart (valves) directly from the deceased donor into the recipient patient. This procedure holds out the possibility of significant benefit, especially for pediatric patients because these grafts show growth potential after transplant, reducing or eliminating the current need for repeat procedures. The clinical process for donation and transplant of partial heart (PH) grafts generally follows an organ clinical pathway; however, the Food and Drug Administration has recently stated its intent to regulate PH as tissues, raising a host of regulatory considerations. PHT requires donor testing and eligibility determinations within a short, clinically viable timeframe and, similar to organ transplant, involves donor-recipient matching. Waitlist allocation policies that are a regulatory focus of the Organ Procurement and Transplantation Network including equity and efficiency may become relevant. Oversight of PHT by the Organ Procurement and Transplantation Network could be accomplished through interpretation of the vascular composite allograft definition or through designation by the US Department of Health and Human Services of PH grafts as organs. While some clinical questions remain unanswered, it is important to carefully address these regulatory considerations to support the emergence of this innovation and ensure the continued trust of the donating public and the patients who may benefit from PHT.

Calcineurin Inhibitor in NEuRoloGically deceased donors to decrease kidney delayed graft function study: study protocol of the CINERGY Pilot randomised controlled trial

IntroductionMost solid organ transplants originate from donors meeting criteria for death by neurological criteria (DNC). Within the organ donor, physiological responses to brain death increase the risk of ischaemia reperfusion...

Fueling the success of transplantation through nutrition: recent insights into nutritional interventions, their interplay with gut microbiota and cellular mechanisms

Purpose of review: The role of nutrition in organ health including solid organ transplantation is broadly accepted, but robust data on nutritional regimens remains scarce calling for further investigation of specific dietary approaches at the different stages of organ transplantation. This review gives an update on the latest insights into nutritional interventions highlighting the potential of specific dietary regimens prior to transplantation aiming for organ protection and the interplay between dietary intake and gut microbiota. Recent findings: Nutrition holds the potential to optimize patients’ health prior to and after surgery, it may enhance patients’ ability to cope with the procedure-associated stress and it may accelerate their recovery from surgery. Nutrition helps to reduce morbidity and mortality in addition to preserve graft function. In the case of living organ donation, dietary preconditioning strategies promise novel approaches to limit ischemic organ damage during transplantation and to identify the underlying molecular mechanisms of diet-induced organ protection. Functioning gut microbiota are required to limit systemic inflammation and to generate protective metabolites such as short-chain fatty acids or hydrogen sulfide. Summary: Nutritional intervention is a promising therapeutic concept including the pre- and rehabilitation stage in order to improve the recipients’ outcome after solid organ transplantation.

European Society for Organ Transplantation (ESOT) Consensus Statement on the Use of Non-invasive Biomarkers for Cardiothoracic Transplant Rejection Surveillance.

While allograft rejection (AR) continues to threaten the success of cardiothoracic transplantation, lack of accurate and repeatable surveillance tools to diagnose AR is a major unmet need in the clinical management of cardiothoracic transplant recipients. Endomyocardial biopsy (EMB) and transbronchial biopsy (TBBx) have been the cornerstone of rejection monitoring since the field's incipience, but both suffer from significant limitations, including poor concordance of biopsy interpretation among pathologists. In recent years, novel molecular tools for AR monitoring have emerged and their performance characteristics have been evaluated in multiple studies. An international working group convened by ESOT has reviewed the existing literature and provides a series of recommendations to guide the use of these biomarkers in clinical practice. While acknowledging some caveats, the group recognized that Gene-expression profiling and donor-derived cell-free DNA (dd-cfDNA) may be used to rule out rejection in heart transplant recipients, but they are not recommended for cardiac allograft vasculopathy screening. Other traditional biomarkers (NT-proBNP, BNP or troponin) do not have sufficient evidence to support their use to diagnose AR. Regarding lung transplant, dd-cfDNA could be used to rule out clinical rejection and infection, but its use to monitor treatment response is not recommended.

Physical exercise, the immune system and infection risk: implications for prehabilitation and rehabilitation for solid organ transplantation candidates and recipients

Physical exercise, the immune system and infection risk: implications for prehabilitation and rehabilitation for solid organ transplantation candidates and recipients

Surveillance for donor‐derived infections in Australia

AbstractBackgroundSystems for quality and safety assurance in organ donation and transplantation are vital, especially those that seek to minimize donor disease transmission. Australia has developed a national vigilance and surveillance system to identify, review, and analyze actual and potential donor‐derived infections and other disease transmissions.MethodsThe system involves notification of incidents to the Australian Organ and Tissue Authority for review by a Vigilance and Surveillance Expert Advisory Committee (VSEAC). The VSEAC grades incidents, O makes recommendations, and issues communications both publicly and to the clinical donation and transplant sector.ResultsAnnual notifications have increased since the inception of the system in 2012 until 2022. The vast majority relate to procedural aspects including donor assessment, information/data issues, and the recovery, offer, allocation, preservation and transportation of organs. Possible donor‐derived disease accounted for 19% of all notifications, and those related to possible donor‐derived infection only 12%. The VSEAC, as a result of reviewing these incidents, has made recommendations resulting in revisions to donor screening, organ allocation, packaging and transportation. The review of incidents has led to changes in clinical guidance for increased viral risk donor assessment, testing, and ensuing organ utilization and recipient surveillance. Guidance has also been reviewed for other infectious risks including strongyloides, human T‐lymphotropic virus, and HEV.ConclusionThe Australian vigilance and surveillance system has enabled national retrospective reporting and evaluation of serious adverse events or reactions to identify trends and inform processes and guidelines, therefore improving the safety of donation and transplantation. image

Innate and adaptive effector immune drivers of cytomegalovirus disease in lung transplantation: a double-edged sword.

Up to 90% of the global population has been infected with cytomegalovirus (CMV), a herpesvirus that remains latent for the lifetime of the host and drives immune dysregulation. CMV is a critical risk factor for poor outcomes after solid organ transplant, though lung transplant recipients (LTR) carry the highest risk of CMV infection, and CMV-associated comorbidities compared to recipients of other solid organ transplants. Despite potent antivirals, CMV remains a significant driver of chronic lung allograft dysfunction (CLAD), re-transplantation, and death. Moreover, the extended utilization of CMV antiviral prophylaxis is not without adverse effects, often necessitating treatment discontinuation. Thus, there is a critical need to understand the immune response to CMV after lung transplantation. This review identifies key elements of each arm of the CMV immune response and highlights implications for lung allograft tolerance and injury. Specific attention is paid to cellular subsets of adaptive and innate immune cells that are important in the lung during CMV infection and reactivation. The concept of heterologous immune responses is reviewed in depth, including how they form and how they may drive tissue- and allograft-specific immunity. Other important objectives of this review are to detail the emerging role of NK cells in CMV-related outcomes, in addition to discussing perturbations in CMV immune function stemming from pre-existing lung disease. Finally, this review identifies potential mechanisms whereby CMV-directed treatments may alter the cellular immune response within the allograft.

Fibrosing cholestatic hepatitis as a variant of the course of hepatotropic viruses’ infection

Fibrosing cholestatic hepatitis is a special variant of infectious hepatitis, with a rapid progressive deterioration of liver function, and usually results in immunosuppression. It has also been reported in patients with immunocompetent status having viral hepatitis B and C. Fibrosing cholestatic hepatitis is diagnosed based on the histological examination of the liver tissue, which reveals severe damage to hepatocytes with pronounced ballooning over a weak inflammatory reaction, pericellular and perisinusoidal fibrosis, and intracellular and tubular cholestases. Analysis of the literature confirms the authors’ assumption that pathological changes in the liver, described as fibrosing cholestatic hepatitis, can develop in different conditions under the influence of various infectious agents. Despite the availability of effective antiviral therapy for hepatitis B and C, the outcomes of fibrosing cholestatic hepatitis are often unfavorable, particularly in cases not associated with solid-organ transplantation. Currently, because of the emergence of numerous drugs that selectively act on the immune system and the development of new areas of medicine such as hematology, rheumatology, oncology, transplantology, and infectious diseases, doctors in these specialties increasingly encounter severe liver damage in patients receiving specific therapy. The authors believe that doctors who do not work at liver transplantation centers underestimate the possibility of fibrosing cholestatic hepatitis development in patients with viral hepatitis B and C, in the clinic of infectious and internal diseases.

Exercise training in solid organ transplant candidates and recipients.

Exercise training programs are an integral part of the management of solid organ transplantation (SOT) candidates and recipients. Despite this, they are not widely available and specific guidelines on exercise parameters for each type of organ are not currently provided. A review of this topic could help clinicians to prescribe appropriate exercise regimens for their patients. In this narrative review, we discuss the physical impairments of SOT candidates and recipients and how these affect their physical function and transplant outcomes. We examine recent systematic reviews, statements, and randomized controlled trials on exercise training in SOT candidates and recipients and present the current available evidence while providing some practical recommendations for clinicians based on the frequency, intensity, time, and type principle. While randomized controlled trials of better methodology quality are needed to strengthen the evidence for the effects of exercise training and for the optimal training characteristics, the available evidence points to beneficial effects of many different types of exercise. The current evidence can provide some guidance for clinicians on the prescription of exercise training for transplant candidates and recipients.

The Liver Frailty Index: a model for establishing organ-specific frailty metrics across all solid organ transplantation.

In this review, we discuss the development of the Liver Frailty Index (LFI) and how it may serve as a model for developing other organ-specific frailty indices. As the demand for solid organ transplants continues to increase, the transplantation community is enhancing its strategies for organ allocation to gain deeper insights into patient risk profiles and anticipated outcomes. Frailty has emerged as a critical concept in transplant care, offering valuable insights into adverse health outcomes. Standardizing frailty assessment across transplant programs could enhance prognostic accuracy and inform pretransplant interventions.The LFI comprises of three performance-based tests that each represents essential components of the multidimensional frailty construct. This composite metric provides insights beyond liver function and considers nonhepatic comorbid factors. Identifying common frailty principles among all transplant candidates and adopting the LFI methodology, which assesses fundamental frailty principles using liver-specific tools, could establish a foundational pool of shared core frailty principles. From this pool, organ-specific frailty indices could be derived, each equipped with the clinically relevant organ-specific tools to evaluate common core principles. Creating a standardized framework across all solid-organ transplants, with common principles and organ-specific measurements, would facilitate consistent frailty assessment, standardize the integration of the frailty construct into transplant decision-making, and enable center-level interventions to improve outcomes for patients with end-stage organ disease.

Immunosuppression at ICU admission is not associated with a higher incidence of ICU-acquired bacterial bloodstream infections: the COCONUT study

BackgroundImmunosuppression at intensive care unit (ICU) admission has been associated with a higher incidence of ICU-acquired infections, some of them related to opportunistic pathogens. However, the association of immunosuppression with the incidence, microbiology and outcomes of ICU-acquired bacterial bloodstream infections (BSI) has not been thoroughly investigated.MethodsRetrospective single-centered cohort study in France. All adult patients hospitalized in the ICU of Lille University-affiliated hospital for > 48 h between January 1st and December 31st, 2020, were included, regardless of their immune status. Immunosuppression was defined as active cancer or hematologic malignancy, neutropenia, hematopoietic stem cell and solid organ transplants, use of steroids or immunosuppressive drugs, human immunodeficiency virus infection and genetic immune deficiency. The primary objective was to compare the 28-day cumulative incidence of ICU-acquired bacterial BSI between immunocompromised and non-immunocompromised patients. Secondary objectives were to assess the microbiology and outcomes of ICU-acquired bacterial BSI in the two groups.ResultsA total of 1313 patients (66.9% males, median age 62 years) were included. Among them, 271 (20.6%) were immunocompromised at ICU admission. Severity scores at admission, the use of invasive devices and antibiotic exposure during ICU stay were comparable between groups. Both prior to and after adjustment for pre‐specified baseline confounders, the 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between immunocompromised and non-immunocompromised patients. The distribution of bacteria was comparable between groups, with a majority of Gram-negative bacilli (~ 64.1%). The proportion of multidrug-resistant bacteria was also similar between groups. Occurrence of ICU-acquired bacterial BSI was associated with a longer ICU length-of-stay and a longer duration of invasive mechanical ventilation, with no significant association with mortality. Immune status did not modify the association between occurrence of ICU-acquired bacterial BSI and these outcomes.ConclusionThe 28-day cumulative incidence of ICU-acquired bacterial BSI was not statistically different between patients with and without immunosuppression at ICU admission.

Changes in post-transplant serum testosterone levels in men undergoing lung transplantation: a pilot study using the TriNetX Research Network.

Hypogonadism is understudied in men requiring solid organ transplants, particularly among lung transplant recipients. Improvement in serum testosterone levels has been reported in kidney and liver transplantation. Using the TriNetX Research Network, we performed a retrospective cohort study to evaluate the incidence of peri-transplant hypogonadism and the natural course of serum testosterone following successful lung transplantation. Men aged ≥ 18 with a lung transplant and total testosterone drawn within one year pre- and post-transplant were included. Men with receipt of testosterone therapy were excluded. A low testosterone (<300 ng/dL) and normal testosterone (≥300 ng/dL) cohort was created before employing descriptive and analytic statistics to investigate the incidence of peri-transplant hypogonadism and the change in serum testosterone levels following lung transplantation. In our entire cohort, lung transplantation was not associated with a significant increase in post-transplant serum testosterone (329.86 ± 162.56 ng/dL pre-transplant and 355.13 ± 216.11 ng/dL post-transplant, p = 0.483). The number of men with low testosterone decreased by 9.8% following lung transplantation but was not significant, p = 0.404. In this pilot study, no significant change in the number of hypogonadal men nor serum testosterone levels was observed among men undergoing lung transplantation.

The impact of immunosuppression on the mortality and hospitalization of Monkeypox: a systematic review and meta-analysis of the 2022 outbreak

BackgroundLimited data is available regarding the severity and mortality of Mpox in individuals with immunocompromised conditions. Therefore, we performed this meta-analysis to understand the impact of HIV- or non-HIV-associated immunosuppression on the severity of Mpox requiring hospitalization and mortality.MethodsA thorough literature search was performed from 2022 up to January 2024. The results were presented as odds ratios (ORs). We only included patients who required hospitalization for severity rather than isolation.ResultsA total of 34 studies were included in this analysis. Our analysis did not find a significant difference in the hospitalization risk between HIV-positive individuals and those who were HIV-negative (OR = 1.03; P = 0.85; 7 studies; CD4 count of fewer than 200 cells/µL was less than 0.5% across all studies). Patients with a CD4 count lower than 200 cells/µL or an unsuppressed RNA viral load (> 200 copies/ml) had a significantly higher hospitalization risk (OR = 5.3, P < 0.001) and (OR = 3, P < 0.001), respectively. Most of the reported deaths were reported in patients with HIV with CD4 counts below 200 cells/µL, with some fatal cases occurring in non-HIV immunosuppressed patients, particularly organ transplant recipients. Based on the autopsy findings, Mpox was confirmed in multiple organs, particularly the digestive tract, lung, and testes. Furthermore, some studies documented cases of death that were suspected to be related to hemophagocytic lymphohistiocytosis (HLH) and immune reconstitution inflammatory syndrome (IRIS). Most of the death reports showed concomitant non-Mpox infections at the time of hospitalization and deathConclusionsOur finding shows that Mpox acts as an opportunistic pathogen in immunocompromised individuals. These individuals should be prioritized for early care and closely monitored for signs of deteriorating clinical conditions. Clinical manifestations and autopsy findings strongly suggest Mpox dissemination to multiple organs, particularly the digestive tract, and lungs. However, the presence of concomitant non-Mpox infections complicates the assessment of the attribution of Mpox to death. Caution should be exercised when interpreting data suggesting poorer outcomes in individuals with non-HIV immunosuppression, as current evidence is scarce and further research is needed.

Burden and frequency of viral testing of kidney and non-kidney transplant recipients.

Transplant patients are at risk of infections due to long-term immunosuppression contributing to morbidity and mortality in this population. Post-transplant testing guidelines were established to monitor and guide therapeutic interventions in transplant recipients. We hypothesize that there are gaps in adherence to the recommended frequency of laboratory testing in post-transplant patients. We analyzed national reference laboratory data to compare viral post-transplant infection (PTI) testing frequency with their respective published guidelines to understand patient uptake and compliance. We evaluated the ordering patterns, positivity rates, and frequency of molecular infectious disease tests (MIDTs). We included 345 patients with International Classification of Diseases (ICD)-10 codes for transplant (Z940-Z942, Z944, Z9481, Z9483, Z9484) with at least two tests (within 7 days) in January 2019 and at least one test in December 2020 to find patients in the post-transplant period. We analyzed two cohorts: kidney transplant recipients (KTRs; 40%) and non-KTR (60%) then followed them longitudinally for the study period. In KTR cohort, high-to-low proportion of ordered MIDT was blood BK virus (bBKV) followed by cytomegalovirus (CMV); in non-KTR cohort, CMV was followed by Epstein-Barr virus (EBV). KTR cohort positivity was highest for urine BK virus (uBKV; 58%) followed by EBV (46%), bBKV (40%), and CMV (31%). Non-KTR cohort positivity was highest for uBKV (64%), EBV (51%), CMV (30%), bBKV (8%), and adenovirus (7%). All patients were tested at progressively longer intervals from the date of the first post-transplant ICD-10-coded test. More than 40% of the KTR cohort were tested less frequently for EBV and bBKV, and more than 20% of the non-KTR cohort were tested for EBV less frequently than published guidelines 4 months after transplant. Despite regular testing, the results of MIDT testing for KTR and non-KTR patients in the post-transplant period are not aligned with published guidelines.IMPORTANCEGuidance for post-transplant infectious disease testing is established, however, for certain infections it allows for clinician discretion. This leads to transplant center policies developing their own testing/surveillance strategies based on their specific transplant patient population (kidney, stem cell, etc.). The Organ Procurement and Transplant Network (OPTN) has developed a strategic plan to improve and standardize the transplant process in the US to improve outcomes of living donors and recipients. Publishing national reference lab data on the testing frequency and its alignment with the recommended guidelines for post-transplant infectious diseases can inform patient uptake and compliance for these strategic OPTN efforts.

Cardiac magnetic resonance imaging characterization of acute rejection in a porcine heterotopic heart transplantation model.

Preclinical disease models are important for the advancement of therapeutics towards human clinical trials. One of the difficult tasks of developing a well-characterized model is having a reliable modality with which to trend the progression of disease. Acute rejection is one of the most devastating complications that can occur following organ transplantation. Specifically in cardiac transplantation, approximately 12% of patients will experience at least one episode of moderate or severe acute rejection in the first year. Currently, the gold standard for monitoring rejection in the clinical setting is to perform serial endomyocardial biopsies for direct histological assessment. However, this is difficult to reproduce in a porcine model of acute rejection in cardiac transplantation where the heart is heterotopically transplanted in an abdominal position. Cardiac magnetic resonance imaging is arising as an alternative for serial screening for acute rejection in cardiac transplantation. This is an exploratory study to create and define a standardized cardiac magnetic resonance screening protocol for characterizing changes associated with the presence of acute rejection in this preclinical model of disease. Results demonstrate that increases in T1 mapping, T2 mapping, left ventricular mass, and in late gadolinium enhancement are significantly correlated with presence of acute rejection.

Blockade of CD80/CD86-CD28 co-stimulation augments the inhibitory function of peptide antigen-specific regulatory T cells.

Mixed lymphocyte culture under the blockade of CD80/CD86-CD28 co-stimulation induces anergic (completely hyporesponsive) T cells with immune suppressive function (inducible suppressing T cells: iTS cells). Previously, iTS cell therapy has demonstrated outstanding benefits in clinical trials for organ transplantation. Here, we examined whether peptide antigen-specific iTS cells are inducible. DO 11.10 iTS cells were obtained from splenocytes of BALB/c DO 11.10 mice by stimulation with OVA peptide and antagonistic anti-CD80/CD86 mAbs. When DO 11.10 iTS or Foxp3- DO 11.10 iTS cells were stimulated with OVA, these cells produced IL-13, but not IL-4. DO 11.10 iTS cells decreased IL-4 and increased IL-13 production from OVA-stimulated naïve DO 11.10 splenocytes. When Foxp3+ DO 11.10 iTS cells were prepared, these cells significantly inhibited the production of IL-4 and IL-13 compared with freshly isolated Foxp3+ DO 11.10 T cells. Moreover, an increase in the population expressing OX40, ICOS, and 4-1BB suggested activation of Foxp3+ DO 11.10 iTS cells. Thus, blockade of CD80/CD86-CD28 co-stimulation during peptide antigen stimulation augments the inhibitory function of Foxp3+ regulatory T cells, and does not induce anergic Foxp3- conventional T cells. Peptide-specific Foxp3+ regulatory iTS cells could be useful for the treatment of allergic and autoimmune diseases without adverse effects.

Is Donation after Circulatory Determination of Death in Japan Uncontrolled or Controlled?

Using donation after circulatory determination of death (DCD) donors has been shown to be a potential means of increasing the number of donors for organ transplantation. The purpose of this study was to examine the published practice of DCD in Japan to properly define their practice as controlled or uncontrolled. Through the Web of Science database, we systematically searched articles describing uncontrolled DCD, controlled DCD or Maastricht classification. A total of 12 articles (ten articles related to kidney, one to pancreas, another to islet transplantation), which were published between 1999 and 2023 from Japanese institutes, were eligible for our study. Systematic review revealed that most DCD in Japan occurs when a terminally ill patient undergoes an expected cardiac arrest without rapid discontinuation from a ventilator, and in some cases with premortem interventions such as cannulation to the femoral vessels. Surprisingly, these DCD donors in Japan have been categorized as uncontrolled DCD. This categorization confuses the donation and transplantation community globally because the international consensus is that uncontrolled DCD occurs after an unexpected cardiac arrest. Further clear definition of terminology would be required within Japan as well as other countries practicing uncontrolled DCD.