Immune response against bacterial infection in organ transplant recipients.

This comprehensive review delves into the intricate dynamics between the immune system and bacterial infections in organ transplant recipients. Its primary objective is to fill existing knowledge gaps while critically assessing the strengths and weaknesses of current research. The paper accentuates the delicate balance that must be struck between preventing graft rejection through immunosuppression and maintaining robust immunity against bacterial threats. In this context, personalized medicine emerges as a transformative concept, offering the potential to revolutionize clinical outcomes by tailoring immunosuppressive regimens and vaccination strategies to the unique profiles of transplant recipients. By emphasizing the pivotal role of continuous monitoring, the review underscores the necessity for vigilant surveillance of transplant recipients to detect bacterial infections and associated immune responses early, thereby reducing the risk of severe infections and ultimately improving patient outcomes. Furthermore, the study highlights the significance of the host microbiome in shaping immune responses, suggesting that interventions targeting the microbiome hold promise for enhancing bacterial immunity in transplant recipients, both in research and clinical practice. In terms of future research directions, the review advocates for large-scale, longitudinal studies encompassing diverse patient cohorts to provide more comprehensive insights into post-transplant immune responses. It also advocates integrating multi-omics approaches, including genomics, transcriptomics, proteomics, and microbiome data, to understand immune responses and their underlying mechanisms. In conclusion, this review significantly enriches our understanding of immune responses in transplant recipients. It paves the way for more effective and personalized approaches to managing infections in this complex setting.

Characterization of the Antibody Response to SARS-CoV-2 Infection in COVID-19 Transplant versus Nontransplant Recipients by Ig-MS.

Solid organ transplant recipients with immunosuppressant regimens to prevent rejection are less able to mount effective immune responses to pathogenic infection. Here, we apply a recently reported mass spectrometry-based serological approach known as Ig-MS to characterize immune responses against infection with SARS-CoV-2 in cohorts of transplant recipients and immunocompetent controls, both at a single early time point following COVID-19 diagnosis as well as over the course of one-month postdiagnosis. We found that the antibody repertoires generated by transplant recipients against SARS-CoV-2 do not differ significantly compared to immunocompetent individuals with regard to repertoire titer, clonality, or glycan composition. Importantly, our study is the first to characterize the evolution of antibody glycan profiles in transplant recipients with COVID-19 disease, presenting evidence that the evolution of glycan composition in these immunocompromised individuals is similar to that in immunocompetent people.

Incidence of de novo malignancy and all-cause mortality among heart transplant recipients.

BACKGROUND: Heart transplant recipients develop cancer at two-times the rate compared to the general population. However, the incidence and mortality rates and the adjusted association between cancer and mortality remains unclear. METHODS: We estimated the incidence and mortality rates and the adjusted association between developing cancer (any, skin, hematologic, and solid tumor subtypes) and the all-cause mortality rates among adult heart transplant recipients from the Scientific Registry of Transplant Recipients from October 1, 1987, until June 28, 2020. RESULTS: Among 51,597 adult heart transplant recipients, 13,191 (25.6%) were diagnosed with de novo malignancy throughout the follow-up period. The cumulative incidence cancer at years 1, 5, 10, and 20 was 3%, 16.4%, 32.8%, and 56.6%, respectively. Among those with cancer, the cumulative mortality was 17.5%, 42.3%, 65%, and 91% at years 1, 5, 10, and 20, respectively. The incidence rate of any de novo malignancy was 38.7 cases per 1000 person-years and the mortality rate (for those with cancer) was 115.2 cases per 1000 person-years. Compared to those without cancer, those with cancer had a higher adjusted mortality association [HR: 2.14 (2.07, 2.21)]. The strongest associations were estimated for pancreatic [10.63 (8.34, 13.54)], leukemia [8.06 (4.33, 15.00)], and esophagus [6.94 (5.43, 8.87)] malignancies. The association between de novo malignancies and mortality was higher in the earlier years of follow-up. CONCLUSION: Compared to not developing cancer, those with de novo malignancy have a 2-fold higher mortality rate, on average. The strength of the association varies by cancer subtype and by follow-up time.

In Defense of Normothermic Regional Perfusion.

Normothermic regional perfusion (NRP) is a relatively new approach to procuring organs for transplantation. After circulatory death is declared, perfusion is restored to either the thoracoabdominal organs (in TA-NRP) or abdominal organs alone (in A-NRP) using extracorporeal membrane oxygenation. Simultaneously, surgeons clamp the cerebral arteries, causing a fatal brain injury. Critics claim that clamping the arteries is the proximate cause of death in violation of the dead donor rule and that the procedure is therefore unethical. We disagree. This account does not consider the myriad other factors that contribute to the death of the donor, including the presence of a fatal medical condition, the decision to withdraw life support, and the physician's actions in withdrawing life support and administering medication that may hasten death. Instead, we claim that physicians play a causative role in many of the events that lead to a patient's death and that these actions are often ethically and legally justified. We advance an "all things considered" view according to which TA-NRP may be considered ethically acceptable insofar as it avoids suffering and respects the wishes of the patient to improve the lives of others through organ donation. We conclude with a series of critical questions related to the practice of NRP and call for the development of national consensus on this issue in the United States.

Assessing the Brain Death/Death by Neurologic Criteria Determination Process in Korea: Insights from 10-Year Noncompleted Donation Data.

BACKGROUND: This study aimed to analyze the current status of brain death/death by neurologic criteria (BD/DNC) determination in Korea over a decade, identifying key areas for improvement in the process. METHODS: We conducted a retrospective analysis of data from the Korea Organ Donation Agency spanning 2011 to 2021, focusing on donors whose donations were not completed. The study reviewed demographics, medical settings, diagnoses, and outcomes, with particular emphasis on cases classified as nonbrain death and those resulting in death by cardiac arrest during the BD/DNC assessment. RESULTS: Of the 5047 patients evaluated for potential brain death from 2011 to 2021, 361 were identified as noncompleted donors. The primary reasons for noncompletion included nonbrain death (n = 68, 18.8%), cardiac arrests during the BD/DNC assessment process (n = 80, 22.2%), organ ineligibility (n = 151, 41.8%), and logistical and legal challenges (n = 62, 17.2%). Notably, 25 (36.8%) of them failed to meet the minimum clinical criteria, and 7 of them were potential cases of disagreement between the two clinical examinations. Additionally, most cardiac arrests (n = 44, 55.0%) occurred between the first and second examinations, indicating management challenges in critically ill patients during the assessment period. CONCLUSIONS: Our study highlights significant challenges in the BD/DNC determination process, including the need for improved consistency in neurologic examinations and the management of critically ill patients. The study underscores the importance of refining protocols and training to enhance the accuracy and reliability of brain death assessments, while also ensuring streamlined and effective organ donation practices.

Culturally Safe Care Barriers and Facilitators in Organ Transplantation and Donation According to First Nations and Health Professionals in Quebec, Canada.

Introduction: First Nations are most at risk of developing end-stage kidney disease. Kidney transplantation is the best treatment option for these patients; however, First Nations donors are underrepresented. The aim of this study was to describe and understand barriers and facilitators of culturally safe organ transplantation and donation from the perspective of First Nations and Health Professionals in the Province of Quebec, Canada. Methods/Approach: This was a qualitative descriptive study using the decolonizing Two-Eyed Seeing approach. The sample consisted of First Nations people and health professionals living in Quebec, Canada, who have had an experience of organ transplantation or donation. Semi-structured interviews were conducted between May and September 2021 with 11 people, including 5 healthcare professionals and 6 First Nations people. Findings: This study enrolled 11 participants. Several individual and contextual factors influencing culturally safe organ transplantation and donation among First Nations people were identified: language barrier, impacts of relocation, lack of knowledge about transplantation, mistrust of the healthcare system, family support and accompaniment, and transplant testimonials. Discussion: This study identified several avenues for reinforcing culturally safe transplantation and donation among First Nations, including the presence of a companion in medical consultations, focusing on access to culturally safe accommodation and sharing transplant testimonials. Further work in partnership with First Nations is needed to improve access to culturally safe organ transplantation.

A 25-year scoping review of the organ donation system in Malaysia: past, present, and future.

Organ donation and transplantation are integral components of modern medicine. This scoping review thoroughly explores the historical evolution, current status, and future prospects of organ donation and transplantation in Malaysia. Historically, Malaysia faced significant challenges in establishing a robust organ transplantation system, with various factors hindering organ donation efforts. Currently, Malaysia continues to struggle with stagnant donation rates despite collaborative efforts from various sectors. There is an urgent need to amend the 50-year-old Human Tissue Act to strengthen the legal framework for organ donation and address ethical concerns. Looking to the future, Malaysia could adopt a soft opt-out system and prioritize advancements in organ preservation techniques by exploring new sources of organs through the donation after circulatory death program. Continued efforts are necessary to enhance education programs for professionals and the public, dispelling myths about organ donation and effectively educating on the concepts of brain death. Malaysia strives to create a more accessible future for organ transplantation, aligning with the Sustainable Development Goals to reduce the burden of organ failure and improve the population's health and well-being.

TLR4 signalling in ischemia/reperfusion injury: a promising target for linking inflammation, oxidative stress and programmed cell death to improve organ transplantation outcomes.

Transplantations represent the principal therapeutic interventions for terminal organ failure, a procedure that has salvaged myriad lives annually. Ischemia/reperfusion injury (IRI) is frequently correlated with an unfavourable prognosis and is relevant for early graft dysfunction and graft survival. IRI constitutes a complex pathological state influenced by a series of factors such as oxidative stress, metabolic stress, leukocytic infiltration, programmed cell death pathways, and inflammatory immune responses. Reducing ischemia/reperfusion injury is one of the main directions of transplantation research. Toll-like receptors (TLRs) are important pattern-recognition receptors expressed on various organs that orchestrate the immune responses upon recognising PAMPs and DAMPs. Targeting the TLR4 signalling has recently been suggested as a promising approach for alleviating IRI by affecting inflammation, oxidative stress and programmed cell death (PCD). In this minireview, we summarise the role of TLR4 signalling in regulating inflammation, oxidative stress and PCD in organ transplantation and discuss their interactions during IRI. A detailed understanding of the multiple functions of TLR4 in IRI provides novel insights into developing therapies to improve organ transplantation outcomes.

Case report: safety and efficacy of lidocaine infusion for the treatment of intractable zoster-associated neuralgia in solid organ transplant recipients.

Introduction: Solid organ transplant recipients are at high risk for developing severe zoster-associated neuralgia, and the pharmaceutic therapies of pain management for these patients with limited organ function are challenging. Intravenous lidocaine infusion showed positive analgesic effects and is used for the management of neuropathic pain. This case series reports the safety and effectiveness of intravenous lidocaine infusion in the treatment of intractable zoster-associated neuralgia in solid organ transplant recipients. Case series presentation: Five solid organ transplant recipients suffering from refractory zoster-associated neuralgia (numeric rating scale 8-10, despite using high doses of antiepileptic drugs or combined with opioids) were enrolled. Intravenous lidocaine (5 mg/kg ideal bodyweight) was administered over 1.5 h with the monitoring of vital signs. Pain intensity, patient satisfaction, adverse events, typical liver, and kidney function were evaluated. All subjects reported high satisfaction with their treatment and effective pain relief at the 6-month follow-up. One patient experienced short and mild numbness in the mouth and dizziness after the therapy, but no major adverse reactions were reported. Conclusion: This case series provides evidence that intravenous lidocaine infusion provided effective pain relief as an analgesic treatment option for transplant patients with intractable zoster-associated neuralgia.

Simultaneous combined transplantation: Intricacies in immunosuppression management.

Simultaneous combined transplantation (SCT), i.e. the transplantation of two solid organs within the same procedure, can be required when the patients develop more than one end-stage organ failure. The development of SCT over the last 20 years could only be possible thanks to progress in the surgical techniques and in the perioperative management of patients in an ageing population. Performing such major transplant surgeries from the same donor, in a short amount of time, and in critical pathophysiological conditions, is often considered to be counterbalanced by the immune benefits expected from these interventions. However, SCT includes a wide array of different transplant combinations, with each time a different immunological constellation. Recent research offers new insights into the immune mechanisms involved in these different settings. Progress in the understanding of these immunological intricacies help to address the optimal induction and maintenance immunosuppressive treatment strategies. In this review, we summarize the different immunological benefits according to the type of SCT performed. We also incorporate the main outcomes according to the immunological risk at transplantation, and the deleterious impact of preformed or de novo donor-specific antibodies (DSA) in the different types of SCT. Finally, we propose comprehensive and evidence-based induction and maintenance immunosuppression strategies guided by the type of SCT.

Cryptococcus neoformans fungemia in a liver transplant patient: Case report and literature review.

Cryptococcus neoformans is an environmental fungus that can frequently cause life-threatening meningitis and fungemia in acquired immunodeficiency syndrome patients. In recent years, cases of these fungal infections are increasingly identified in HIV-negative patients especially in solid organ transplantation (SOT) patients. Cryptococcal fungemia can often clinically present as life-threatening disseminated disease from subclinical colonization. This is a factor that affects survival, especially in patients with decompensated liver cirrhosis and SOT recipients. Early diagnosis and appropriate treatment are important for the course of the disease. This report describes the cryptococcal fungemia that developed in an HIV-negative patient after SOT due to alcohol-related liver cirrhosis.

Psychological Health of the Adolescent Transplant Recipient.

BACKGROUND: Solid organ transplant recipients experience a period of unique vulnerability during adolescence, when normative developmental changes intersect with health-related variables to influence psychological health. METHODS: This article builds on previous reviews of psychological health in solid organ transplant recipients and proposes opportunities for clinical intervention during adolescence. RESULTS: Transplant recipients often experience neurocognitive changes, particularly with respect to executive functions, that impact health management tasks and autonomous care. Recipients should be monitored for the development of anxiety, depression, and posttraumatic stress symptoms during adolescence, which in turn can negatively impact adherence to immunosuppression. Recent research in posttraumatic growth and resiliency factors may represent a promising avenue of intervention, leveraging normative developmental processes during this time period. CONCLUSIONS: As pediatric transplant providers, adolescence represents a developmental period for targeted interventions to foster adjustment and adherence and promote a successful transition to adult care.

LiverColor: An Artificial Intelligence Platform for Liver Graft Assessment.

Hepatic steatosis, characterized by excess fat in the liver, is the main reason for discarding livers intended for transplantation due to its association with increased postoperative complications. The current gold standard for evaluating hepatic steatosis is liver biopsy, which, despite its accuracy, is invasive, costly, slow, and not always feasible during liver procurement. Consequently, surgeons often rely on subjective visual assessments based on the liver's colour and texture, which are prone to errors and heavily depend on the surgeon's experience. The aim of this study was to develop and validate a simple, rapid, and accurate method for detecting steatosis in donor livers to improve the decision-making process during liver procurement. We developed LiverColor, a co-designed software platform that integrates image analysis and machine learning to classify a liver graft into valid or non-valid according to its steatosis level. We utilized an in-house dataset of 192 cases to develop and validate the classification models. Colour and texture features were extracted from liver photographs, and graft classification was performed using supervised machine learning techniques (random forests and support vector machine). The performance of the algorithm was compared against biopsy results and surgeons' classifications. Usability was also assessed in simulated and real clinical settings using the Mobile Health App Usability Questionnaire. The predictive models demonstrated an area under the receiver operating characteristic curve of 0.82, with an accuracy of 85%, significantly surpassing the accuracy of visual inspections by surgeons. Experienced surgeons rated the platform positively, appreciating not only the hepatic steatosis assessment but also the dashboarding functionalities for summarising and displaying procurement-related data. The results indicate that image analysis coupled with machine learning can effectively and safely identify valid livers during procurement. LiverColor has the potential to enhance the accuracy and efficiency of liver assessments, reducing the reliance on subjective visual inspections and improving transplantation outcomes.

Risk factors for severe outcomes of coronavirus disease 2019 through the waves of the pandemic: Comparing patients with and without solid organ transplantation.

BACKGROUND: While coronavirus disease 2019 (COVID-19) is no longer a public health emergency, certain patients remain at risk of severe outcomes. To better understand changing risk profiles, we studied the risk factors for patients with and without solid organ transplantation (SOT) through the various waves of the pandemic. METHODS: Using the National COVID Cohort Collaborative we studied a cohort of adult patients testing positive for COVID-19 between January 1, 2020, and May 2, 2022. We separated the data into waves of COVID-19 as defined by the Centers for Disease Control. In our primary outcome, we used multivariable survival analysis to look at various risk factors for hospitalization in those with and without SOT. RESULTS: A total of 3,570,032 patients were captured. We found an overall risk attenuation of adverse COVID-19-associated outcomes over time. In both non-SOT and SOT populations, diabetes, chronic kidney disease, and congestive heart failure were risk factors for hospitalization. For SOT specifically, longer time periods between transplant and COVID-19 were protective and age was a risk factor. Notably, asthma was not a risk factor for major adverse renal cardiovascular events, hospitalization, or mortality in either group. CONCLUSIONS: Our study provides a longitudinal view of the risks associated with adverse COVID-related outcomes amongst SOT and non-SOT patients, and how these risk factors evolved over time. Our work will help inform providers and policymakers to better target high-risk patients.

Bringing optimised COVID-19 vaccine schedules to immunocompromised populations (BOOST-IC): study protocol for an adaptive randomised controlled clinical trial.

BACKGROUND: Immunocompromised hosts (ICH) experience more breakthrough infections and worse clinical outcomes following infection with COVID-19 than immunocompetent people. Prophylactic monoclonal antibody therapies can be challenging to access, and escape variants emerge rapidly. Immunity conferred through vaccination remains a central prevention strategy for COVID-19. COVID-19 vaccines do not elicit optimal immunity in ICH but boosting, through additional doses of vaccine improves humoral and cellular immune responses. This trial aims to assess the immunogenicity and safety of different COVID-19 vaccine booster strategies against SARS-CoV-2 for ICH in Australia. METHODS: Bringing optimised COVID-19 vaccine schedules to immunocompromised populations (BOOST-IC) is an adaptive randomised trial of one or two additional doses of COVID-19 vaccines 3 months apart in people living with HIV, solid organ transplant (SOT) recipients, or those who have haematological malignancies (chronic lymphocytic leukaemia, non-Hodgkin lymphoma or multiple myeloma). Key eligibility criteria include having received 3 to 7 doses of Australian Therapeutic Goods Administration (TGA)-approved COVID-19 vaccines at least 3 months earlier, and having not received SARS-CoV-2-specific monoclonal antibodies in the 3 months prior to receiving the study vaccine. The primary outcome is the geometric mean concentration of anti-spike SARS-CoV-2 immunoglobulin G (IgG) 28 days after the final dose of the study vaccine. Key secondary outcomes include anti-spike SARS-CoV-2 IgG titres and the proportion of people seroconverting 6 and 12 months after study vaccines, local and systemic reactions in the 7 days after vaccination, adverse events of special interest, COVID-19 infection, mortality and quality of life. DISCUSSION: This study will enhance the understanding of COVID-19 vaccine responses in ICH, and enable the development of safe, and optimised vaccine schedules in people with HIV, SOT, or haematological malignancy. TRIAL REGISTRATION: ClinicalTrials.gov NCT05556720. Registered on 23rd August 2022.

Case report: Liver PEComa after kidney transplantation in recipient with tuberous sclerosis complex.

Introduction: Perivascular epithelioid cell tumors (PEComa) are rare tumors of mesenchymal origin that exhibit perivascular epithelioid cell phenotype. One of its most common localizations is uterus, whereas only a few studies reported PEComa localization as liver. There is a correlation between the presence of PEComa and tuberous sclerosis complex (TSC). TSC is a rare disease which leads to the development of mostly non-cancerous tumors in various organs. We would like to present a case of a kidney transplant recipient with a PEComa detected post-transplant in the liver. Case report: A 27-year-old patient, 3 years after kidney transplantation (KTx) due to chronic renal failure in the course of autosomal dominant polycystic kidney disease and concomitant TSC, was admitted to the Clinic and Department of General and Transplant Surgery for abnormal findings in computed tomography (CT). A CT scan was conducted for oncological follow-up after a kidney transplant (KTx) because before the transplantation, a small cystic lesion measuring 7 mm in diameter was removed from the donor kidney and diagnosed as papillary renal cell carcinoma (PRCC). Two tumors in the liver were detected - one 27mm in diameter in segment VII/VIII and the other 8mm in diameter in segment II/III. Because of typical radiological signs hepatocellular carcinoma was suspected, but the serum level of alpha fetoprotein was within normal limits and liver function was preserved. The intraoperative biopsy and the radiofrequency ablation (RFA) of the larger tumor were performed three months later. In the histopathological examination benign PEComa (HMB45 +, Melan A +) was detected. Conclusion: The oncological surveillance made it possible to detect liver lesion in early stage and in 3,5-year follow-up no sign of recurrence of PEComa was found. This case is the second to show RFA as treatment method of liver PEComa and first in kidney transplant recipient.

Measuring patient-reported experience of solid organ transplantation healthcare: A scoping review of condition- and transplant-specific measures.

BACKGROUND: Measures of patient experience are increasingly valued as key to healthcare quality assessment. We aimed to identify and describe publicly available measures assessing patient-reported experience of solid organ transplantation healthcare, and identify patient groups, healthcare settings, or aspects of patient experience underserved by existing measures. METHODS: We systematically searched MEDLINE, Embase, CINAHL, PsycINFO, Cochrane CENTRAL, Scopus and Web of Science from inception to 6th July 2023; supplemented with grey literature searches. Two reviewers independently screened search hits; outputs reporting patient-reported measures of multiple aspects of established solid organ transplantation healthcare were eligible. We abstracted measure context, characteristics, content (i.e., attributes of patient experience assessed), and development and validation processes. RESULTS: We identified nine outputs reporting eight measures of patient experience; these related only to kidney (n = 5) or liver (n = 3) transplantation, with no available measures relating to heart, lung, pancreas or intestinal transplantation. Of the identified measures, four were specific to solid organ transplant recipients. Measures sought to assess "patient satisfaction" (n = 4) and "patient experience" (n = 4) of healthcare. Measures mapped to between five and 16 of 20 attributes of patient experience, most often Information and education, Communication, and Access to care (all n = 7). Six measures reported a development process, only three reported a validation process. CONCLUSIONS: Publicly available patient-reported measures of organ transplantation healthcare experiences are limited to kidney and liver transplantation. There is heterogeneity in measure context, characteristics, and content, and insufficient clarity concerning how well measures capture the specific experiences of transplant recipients. Formalised measures of patient experience, specific to solid organ transplantation, with transparent reporting of development and validity are needed.

A Digital Approach to Improve Infection Screening Among Solid Organ Transplant Candidates.

BACKGROUND: Pretransplant infection screening (IS) of potential organ recipients is essential to optimal outcome of solid organ transplantation (SOT). METHODS: A pre-post study was performed during 2020-2023 to investigate the impact of the STREAM (Solid organ TRansplant stEwArdship and Multidisciplinary approach) intervention to improve IS in SOT. The intervention, performed in 2022, included the implementation of IS through educational meetings, local guidelines, and the availability of a digital screening tool. The objective of the study was the assessment of IS completion, including a list of 17 laboratory tests and the investigation of vaccination status. The reduction of unnecessary tests was also analyzed. The test of proportions and a multilevel multivariate Poisson regression model were used to compare IS completion before and after STREAM. infectious diseases (ID) consultation and urgent evaluation were investigated as predictors of IS completion. RESULTS: A total of 171 patients were enrolled, including liver (44%), heart (32%), and kidney (24%) transplant candidates. Mean age was 56 ± 11 years, and most patients (77%) were males. Ninety-five (56%) patients were included before the intervention and 76 (44%) after STREAM. IS completion increased after STREAM (IRR 1.41, p < 0.001) with significant improvement recorded for seven (39%) IS items. Unnecessary tests decreased by 43% after the intervention. ID consultation (IRR 1.13, p = 0.02) and urgent evaluation (p = 0.68, p < 0.001) were predictors of IS improvement. CONCLUSIONS: STREAM was successful in improving IS completion. Further research is needed to investigate the impact of this intervention on posttransplant infections.