Infection in Organ Transplantation

From islet transplantation to beta-cell regeneration: an update on beta-cell-based therapeutic approaches in type 1 diabetes

INTRODUCTION

Type 1 diabetes (T1D) mellitus is an autoimmune disease in which immune cells, predominantly effector T cells, destroy insulin-secreting beta-cells. Beta-cell destruction led to various consequences ranging from retinopathy and nephropathy to neuropathy. Different strategies have been developed to achieve normoglycemia, including exogenous glucose compensation, whole pancreas transplantation, islet transplantation, and beta-cell replacement.

AREAS COVERED

The last two decades of experience have shown that indigenous glucose compensation through beta-cell regeneration and protection is a peerless method for T1D therapy. Tremendous studies have tried to find an unlimited source for beta-cell regeneration, on the one hand, and beta-cell protection against immune attack, on the other hand. Recent advances in stem cell technology, gene editing methods, and immune modulation approaches provide a unique opportunity for both beta-cell regeneration and protection.

EXPERT OPINION

Pluripotent stem cell differentiation into the beta-cell is considered an unlimited source for beta-cell regeneration. Devising engineered pancreas-specific regulatory T cells using Chimeric Antigen Receptor (CAR) technology potentiates an effective immune tolerance induction for beta-cell protection. Beta-cell regeneration using pluripotent stem cells and beta-cell protection using pancreas-specific engineered regulatory T cells promises to develop a curative protocol in T1D.

The Predictors and Risk Factors of 2-Year Rejection in Renal Transplant Patients: A Multicenter Case-Control Study

INTRODUCTION

Kidney transplantation is a definitive treatment for end-stage renal disease. It is associated with improved life expectancy and quality of life. One of the most common complications following kidney transplantation is graft rejection. To our knowledge, no previous study has identified rejection risk factors in kidney transplant recipients in Saudi Arabia. Therefore, this study aimed to determine the specific risk factors of graft rejection.

METHODS

A multicenter case-control study was conducted at four transplant centers in Saudi Arabia. All adult patients who underwent a renal transplant between January 1, 2015 and December 31, 2021 were screened for eligibility. Included patients were categorized into two groups (cases and control) based on the occurrence of biopsy-proven rejection within 2 years. The primary outcome was to determine the risk factors for rejection within the 2 years of transplant. Exact matching was utilized using a 1:4 ratio based on patients' age, gender, and transplant year.

RESULTS

Out of 1,320 screened renal transplant recipients, 816 patients were included. The overall prevalence of 2-year rejection was 13.9%. In bivariate analysis, deceased donor status, the presence of donor-specific antibody (DSA), intraoperative hypotension, Pseudomonas aeruginosa, Candida, and any infection within 2 years were linked with an increased risk of 2-year rejection. However, in the logistic regression analysis, the presence of DSA was identified as a significant risk for 2-year rejection (adjusted OR: 2.68; 95% CI: 1.10, 6.49, p = 0.03). Furthermore, blood infection, infected with Pseudomonas aeruginosa or BK virus within 2 years of transplant, were associated with higher odds of 2-year rejection (adjusted OR: 3.10; 95% CI: 1.48, 6.48, p = 0.003, adjusted OR: 3.23; 95% CI: 0.87, 11.97, p = 0.08 and adjusted OR: 2.76; 95% CI: 0.89, 8.48, p = 0.07, respectively).

CONCLUSION

Our findings emphasize the need for appropriate prevention and management of infections following kidney transplantation to avoid more serious problems, such as rejection, which could significantly raise the likelihood of allograft failure and probably death. Further studies with larger sample sizes are needed to investigate the impact of serum chloride levels prior to transplant and intraoperative hypotension on the risk of graft rejection and failure.

Evidence for Immunity against Tetanus, Diphtheria, and Pertussis through Natural Infection or Vaccination in Adult Solid Organ Transplant Recipients: A Systematic Review

(1) Background: We aim to systematically review the current evidence on immunity against tetanus, diphtheria, and pertussis in adult solid organ transplantation (SOT) recipients, either through natural infection or vaccination. (2) Methods: This systematic review was conducted per PRISMA guidelines. We assessed the risk of bias using the Cochrane RoB 2 and ROBINS-I and summarized the findings narratively due to the heterogeneity of the studies. (3) Results: Of the 315 screened articles, 11 were included. Tetanus immunity varied between 55% and 86%, diphtheria immunity from 23% to 75%, and pertussis immunity was between 46% and 82%. Post-vaccination immunity showed variation across the studies, with some indicating reductions and others no change, with antibody responses influenced by transplanted organs, gender, age, and immunosuppressive regimens. The single randomized study exhibited a low risk of bias, while of the ten non-randomized studies, six showed moderate and four serious risks of bias, necessitating cautious interpretation of results. (4) Conclusions: SOT recipients exhibit considerable immunity against tetanus and diphtheria at transplantation, but this immunity decreases over time. Although vaccination can enhance this immunity, the response may be suboptimal, and the increased antibody levels may not persist, underscoring the need for tailored vaccination strategies in this vulnerable population.

Monocentric, Retrospective Study on Infectious Complications within One Year after Solid-Organ Transplantation at a Belgian University Hospital

The epidemiology, diagnostic methods and management of infectious complications after solid-organ transplantation (SOT) are evolving. The aim of our study is to describe current infectious complications in the year following SOT and risk factors for their development and outcome. We conducted a retrospective study in adult SOT recipients in a Belgian university hospital between 2018 and 2019. We gathered demographic characteristics, comorbidities leading to transplantation, clinical, microbiological, surgery-specific and therapeutic data concerning infectious episodes, and survival status up to one year post-transplantation. Two-hundred-and-thirty-one SOT recipients were included (90 kidneys, 79 livers, 35 lungs, 19 hearts and 8 multiple organs). We observed 381 infections in 143 (62%) patients, due to bacteria (235 (62%)), viruses (67 (18%)), and fungi (32 (8%)). Patients presented a median of two (1-5) infections, and the first infection occurred during the first six months. Nineteen (8%) patients died, eleven (58%) due to infectious causes. Protective factors identified against developing infection were obesity [OR [IC]: 0.41 [0.19-0.89]; p = 0.025] and liver transplantation [OR [IC]: 0.21 [0.07-0.66]; p = 0.007]. Risk factors identified for developing an infection were lung transplantation [OR [IC]: 6.80 [1.17-39.36]; p = 0.032], CMV mismatch [OR [IC]: 3.53 [1.45-8.64]; p = 0.006] and neutropenia [OR [IC]: 2.87 [1.27-6.47]; p = 0.011]. Risk factors identified for death were inadequate cytomegalovirus prophylaxis, infection severity and absence of pneumococcal vaccination. Post-transplant infections were common. Addressing modifiable risk factors is crucial, such as pneumococcal vaccination.

Anti-Donor T-Cell Responses Are Not Necessarily Attenuated During Cytomegalovirus Infection in Kidney Transplant Recipients

BACKGROUND

Cytomegalovirus (CMV), the most common opportunistic infection of kidney transplantation (KT), is preventable by prophylactic and preemptive antiviral drugs in CMV-immunoglobulin (Ig)G-positive donors. Our preemptive therapy optimized immunosuppressive doses based on mixed lymphocyte response (MLR) results, regardless of preoperative CMV-IgG serostatus pairing. This study used the MLR to compare the anti-donor T-cell responses between CMV antigenemia-positive and -negative cases.

METHODS

One hundred patients underwent KT using a cyclosporine (CsA)-based immunosuppressive regimen at Hiroshima University Hospital. CMV antigenemia-positive cells were defined as 4/50,000 CMVpp65-positive cells. T-cell responses to allo-antigens were measured using MLR assays to evaluate patients' anti-donor immune reactivity. After analyzing the proliferation of CD4+ and CD8+ T-cell subsets, the stimulation indices of CD4+ or CD8+ T cells were quantified. The study used no prisoners, and the participants were neither coerced nor paid. The manuscript was created in compliance with the Helsinki Congress and the Declaration of Istanbul.

RESULTS

Forty-three patients tested positive for CMV antigenemia within 3 months after KT. No significant differences were found between the CMV antigenemia-positive and -negative groups in the stimulation indices for CD4+ and CD8+ T-cell responses to anti-donor stimulation. However, T-cell responses to third-party stimuli during the postoperative month 1 were significantly less in the CMV antigenemia-positive than -negative group.

CONCLUSION

Anti-donor T-cell responses are not necessarily attenuated during CMV infection in KT recipients. In CMV-infected KT recipients, caution should be exercised against inadvertent dose reduction of immunosuppressants.

Gram-negative bacterial colonizations before bilateral lung transplant. The impact of 'targeted' versus 'standard' surgical prophylaxis

BACKGROUND

Infections are one of the most common causes of death after lung transplant (LT). However, the benefit of 'targeted' prophylaxis in LT recipients pre-colonized by Gram-negative (GN) bacteria is still unclear.

METHODS

All consecutive bilateral LT recipients admitted to the Intensive Care Unit of the University Hospital of Padua (February 2016-2023) were retrospectively screened. Only patients with pre-existing GN bacterial isolations were enrolled and analyzed according to the antimicrobial surgical prophylaxis ('standard' vs. 'targeted' on the preoperative bacterial isolation).

RESULTS

One hundred eighty-one LT recipients were screened, 46 enrolled. Twenty-two (48%) recipients were exposed to 'targeted' prophylaxis, while 24 (52%) to 'standard' prophylaxis. Overall prevalence of postoperative multi-drug resistant (MDR) GN bacteria isolation was 65%, with no differences between the two surgical prophylaxis (p = 0.364). Eleven (79%) patients treated with 'standard' prophylaxis and twelve (75%) with 'targeted' therapy reconfirmed the preoperative GN pathogen (p = 0.999). The prevalence of postoperative infections due to MDR GN bacteria was 50%. Of these recipients, 4 belonged to the 'standard' and 11 to the 'targeted' prophylaxis (p = 0.027).

CONCLUSIONS

The administration of a 'targeted' prophylaxis in LT pre-colonized recipients seemed not to prevent the occurrence of postoperative MDR GN infections.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

A Diagnostic Approach to Fungal Pneumonia: An Infectious Diseases Perspective

Although bacteria significantly exceed fungi as the most common cause of lower respiratory tract infection, the incidence of fungal pneumonia is increasing because of a growing at-risk population of immunocompromised individuals as well as anthropogenic global heating and environmental disruption. When a patient presents with a clinical syndrome of pneumonia, a constellation of factors must be considered to determine the probability of a fungal pneumonia, including host factors, epidemiologic exposures, suggestive radiographic patterns, and the presence of a non-resolving pneumonia. In addition, knowledge of clinically important fungal pathogens, their epidemiology, and associated clinical syndromes are key in guiding appropriate diagnostic testing and result interpretation, and ultimately rendering a correct diagnosis of a fungal pneumonia. This article aims to provide a framework for the evaluation and appropriate diagnostic testing of patients with suspected fungal pneumonia.

Impact of Early Rejection Treatment on Infection Development in Kidney Transplant Recipients: A Propensity Analysis

Introduction

The impact of renal allograft rejection treatment on infection development has not been formally defined in the literature.

Methods

We conducted a retrospective cohort study of 185 rejection (case) and 185 nonrejection (control) kidney transplant patients treated at our institution from 2014 to 2020 to understand the impact of rejection on infection development. Propensity scoring was used to match cohorts. We collected data for infections within 6 months of rejection for the cases and 18 months posttransplant for controls.

Results

In 370 patients, we identified 466 infections, 297 in the controls, and 169 in the cases. Urinary tract infections (38.9%) and cytomegalovirus viremia (13.7%) were most common. Cumulative incidence of infection between the case and controls was 2.17 (CI 1.54-3.05); p < 0.001. There was no difference in overall survival (HR 0.90, CI 0.49-1.66) or graft survival (HR 1.27, CI 0.74-2.20) between the groups. There was a significant difference in overall survival (HR 2.28, CI 1.14-4.55; p = 0.019) and graft survival (HR 1.98, CI 1.10-3.56; p = 0.023) when patients with infection were compared to those without.

Conclusions

As previously understood, rejection treatment is a risk factor for subsequent infection development. Our data have defined this relationship more clearly. This study is unique, however, in that we found that infections, but not rejection, negatively impacted both overall patient survival and allograft survival, likely due to our institution's robust post-rejection protocols. Clinicians should monitor patients closely for infections in the post-rejection period and have a low threshold to treat these infections while also restarting appropriate prophylaxis.

Opportunistic Infections Post-Lung Transplantation: Viral, Fungal, and Mycobacterial

Opportunistic infections are a leading cause of lung transplant recipient morbidity and mortality. Risk factors for infection include continuous exposure of the lung allograft to the external environment, high levels of immunosuppression, impaired mucociliary clearance and decreased cough reflex, and impact of the native lung microbiome in single lung transplant recipients. Infection risk is mitigated through careful pretransplant screening of recipients and donors, implementation of antimicrobial prophylaxis strategies, and routine surveillance posttransplant. This review describes common viral, fungal, and mycobacterial infectious after lung transplant and provides recommendations on prevention and treatment.

Infection prevention for immunocompromised patients: A cross-translational multicentric survey of current organization in France

OBJECTIVES

To evaluate current organization of infection prevention for immunocompromised patients (ICP) at a countrywide level.

METHODS

Nationwide cross-sectional multicenter study based on an online survey disseminated in 2022 to physicians invested with preventive healthcare missions.

RESULTS

A total of 341 physicians (96% graduates, 32% infectious disease specialists), participated in the survey, with a median age of 40 [35-51] years. On-site access to infection prevention consultations for ICP was reported by 30%, dedicated pre-travel consultations for ICPs by 29%, consultations for infection prevention in solid organ transplant candidates by 16% and return-to-work consultations for ICPs by 6%. Most participants (73%) were aware of nationwide vaccination guidelines for ICP, while 50% felt comfortable using them. Tools for infection prevention advice and ICP vaccination had been developed by 10%, while 89% would have appreciated access to tools developed by others.

CONCLUSIONS

Infection prevention for ICPs remains neglected. Guidelines covering all fields of prevention for ICPs would be more than welcome.

Barriers toward xenotransplantation in Arab World

Organ transplant is a crucial therapeutic strategy offering a life-saving and transformative medical intervention. It provides an opportunity to improve their quality of life and increase their lifespan. The shortage of organs remains a critical global challenge, leading to a prolonged waiting times for organ receivers, which contributes to an increase in morbidity and mortality rates. Hence, xenotransplantation offered a promising solution to the global shortage of organs through the use of animal organs, leading to an increase in donor availability, reducing waiting times, minimizing organ trafficking, improving genetic engineering advancements, and driving scientific innovation. Even though xenotransplantation has many benefits in the clinical setting, it has many barriers that are hindering its achievements and constraining its occurrence. Some barriers to xenotransplant are general, such as the immunological barrier, while others are specific to certain regions due to local causes. The Arab region exhibits disparities in clinical settings compared to the global context, marked by the huge economic crisis and a shortage of trained healthcare professionals. Considering the huge resources and advancements needed in the field of xenotransplantation, this review aims to explore the specific barriers toward xenotransplantation in the Arab countries, highlighting the challenges to overcome these barriers.

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.

Beyond the First Year: Epidemiology and Management of Late-Onset Opportunistic Infections After Kidney Transplantation

Late opportunistic infections (OI) occurring beyond the first year after kidney transplantation (KT) are poorly described and not targeted by prophylactic strategies. We performed a ten-year retrospective monocentric cohort study describing epidemiology, risk factors and impact of late OI occurring 1 year after KT. We included clinically symptomatic OI requiring treatment besides BK virus nephropathy. Control groups included early OI occurring in the first year after KT, and KT recipients without OI since KT and alive with a functional allograft at 1 year. Among 1066 KT recipients, 185 (19.4%) presented a first episode of OI 21.0 (8.0-45.0) months after KT: 120 late OI (64.9%) and 65 early OI (35.1%). Late OI were mainly viral (N = 83, 69.2%), mostly herpes zoster (HZ) (N = 36, 43.4%). Pneumocystis represented most late fungal infections (N = 12/25, 48%). Compared to early OI, we reported more pneumocystis (p = 0.002) and less invasive aspergillosis (p = 0.01) among late OI. Patients with late OI were significatively younger at KT (54.0 ± 13.3 vs. 60.2 ± 14.3 years, p = 0.05). Patient and allograft survival rates between late OI and control groups were similar. Only age was independently associated with mortality. While late OI were not associated with higher mortality or graft loss, implementing prophylactic strategies might prevent such infections.

How I approach: the transplant recipient with fever and pulmonary infiltrates

Recipients of hematopoietic stem cell transplants and solid organ transplants frequently develop pulmonary infiltrates from both infectious and non-infectious etiologies. Differentiation and further characterization of microbiologic etiologies-viral, bacterial, and fungal-can be exceedingly challenging. Pediatric patients face unique challenges as confirmatory evaluations with bronchoscopy or lung biopsy may be limited. A generalizable approach to diagnosing and managing these conditions has not been well established. This paper aims to summarize our initial clinical approach while discussing the relative evidence informing our practices. A pediatric patient with characteristic infiltrates who has undergone HSCT is presented to facilitate the discussion. Generalizable approaches to similar patients are highlighted as appropriate while highlighting considerations based on clinical course and key risk factors.

Lung Transplantation from hepatitis C+ donor lungs: Reassuring midterm outcomes

BACKGROUND

The development of modern antiviral therapy for hepatitis C virus (HCV) has allowed for the transplantation of HCV nucleic acid amplification testing-positive (NAT+) donor lungs with acceptable short-term outcomes. We sought to evaluate trends and midterm outcomes of lung transplant recipients of HCV NAT+ donor allografts.

METHODS

All adults undergoing isolated lung transplantation in the United Network for Organ Sharing database from January 2016 to December 2022 were included in the study. Lung transplant recipients were stratified based on donor HCV status (HCV NAT+ vs NAT-). Propensity score matching was used to adjust for differences between groups. Several outcomes, including acute rejection by 1 year, early (30-day and in-hospital) mortality, and both 1- and 3-year survival, were compared between matched groups.

RESULTS

A total of 16,725 patients underwent lung transplantation during the study period, with 489 (3%) receiving HCV NAT+ donor lungs. Regions 1 (18%) and 6/8 (both 0%) had the highest and lowest proportions, respectively, of HCV NAT+ donor transplants. Utilization of HCV NAT+ donors increased throughout the study period from 2 (0.1%) in 2016 to a peak of 117 (5%) in 2019. Donors who were HCV NAT+ were younger (34 vs 36 years, p < 0.001), more often female (44% vs 39%, p < 0.01), and more commonly died due to drug intoxication (56% vs 15%, p < 0.001). Recipients of HCV NAT+ donor lungs were similar in age (62 vs 62 years, p = 0.69) and female gender (43% vs 39%, p = 0.15) but had lower lung allocation scores (38 vs 41, p < 0.001) compared to others. Rates of acute rejection (13% vs 17%, p = 0.09), early mortality (30-day: 2% vs 1%, p = 0.59, in-hospital: 3% vs 4%, p = 0.38), as well as 1-year (90% vs 92%, p = 0.29) and 3-year survival (69% vs 75%, p = 0.13) were not significantly different between matched groups.

CONCLUSIONS

Lung transplant recipients of HCV NAT+ donor allografts experience similar rates of acute rejection, early mortality, and 3-year survival compared to all other lung recipients. Increased use of HCV NAT+ donor allografts may help to expand the donor pool and alleviate donor shortages.

Infections in the first year after heart transplantation in a Latin American country

BACKGROUND

Heart transplantation is the therapy of choice in patients with advanced heart failure refractory to other medical or surgical management. However, heart transplants are associated with complications that increase posttransplant morbidity and mortality. Infections are one of the most important complications after this procedure. Therefore, infections in the first year after heart transplantation were evaluated.

METHODS

A retrospective cohort study of infections after heart transplants was conducted in a teaching hospital in Colombia between 2011 and 2019. Patients registered in the institutional heart transplant database (RETRAC) were included in the study. Microbiological isolates and infectious serological data were matched with the identities of heart transplant recipients and data from clinical records of individuals registered in the RETRAC were analyzed. The cumulative incidences of events according to the type of microorganism isolated were estimated using Kaplan-Meier survival analyses.

RESULTS

Seventy-nine patients were included in the study. Median age was 49 years (37.4-56.3), and 26.58% of patients were women. Eighty-seven infections were documented, of which 55.17% (48) were bacterial, 22.99% (20) were viral, and 12.64% (11) were fungal. Bacterial infections predominated in the first month. In the first year, infections caused 38.96% of hospital admissions and were the second cause of death after heart transplants (25.0%).

CONCLUSION

Posttransplant infections in the first year of follow-up were frequent. Bacterial infections predominated in the early posttransplant period. Infections, mainly bacterial, were the second most common cause of death and the most common cause of hospitalization in the first year after heart transplantation.

Deep cutaneous mycoses in kidney transplant recipients: Diagnostic and therapeutic challenges

Deep cutaneous mycoses (DCMs) are rare infections that extend throughout the dermis and subcutis, often occurring after inoculation with pathogenic fungi. Trends toward a growing incidence have been observed that may be partially related to an increasing population of solid organ transplant patients. The aim of this study is to describe the diagnostics and the outcomes of DCM among kidney transplant recipients so as to optimize their management. We performed a retrospective review of cases of DCM occurring among kidney transplant recipients in our institution over 12 years. Twenty cases were included. Lesions were only located on the limbs and presented mainly as single (10/20, 50%) nodular lesions (15/20, 75%), with a mean size of 3 cm. Direct mycological examination was positive for 17 patients (17/20, 85%) and the cultures were consistently positive. Thirteen different fungal species were observed, including phaehyphomycetes (n = 8), hyalohyphomycetes (n = 3), dermatophytes (n = 1), and mucorale (n = 1). The (1-3) beta-D-glucan antigen (BDG) was also consistently detected in the serum (20/20, 100%). Systematic imaging did not reveal any distant infectious lesions, but locoregional extension was present in 11 patients (11/14, 79%). Nineteen patients received antifungal treatment (19/20, 95%) for a median duration of 3 months, with surgery for 10 (10/20, 50%). There is a great diversity of fungal species responsible for DCMs in kidney transplant recipients. The mycological documentation is necessary to adapt the antifungal treatment according to the sensitivity of the species. Serum BDG positivity is a potentially reliable and useful tool for diagnosis and follow-up.

Dynamics of torque teno virus load in kidney transplant recipients with indication biopsy and therapeutic modifications of immunosuppression

Following kidney transplantation, lifelong immunosuppressive therapy is essential to prevent graft rejection. On the downside, immunosuppression increases the risk of severe infections, a major cause of death among kidney transplant recipients (KTRs). To improve post-transplant outcomes, adequate immunosuppressive therapy is therefore a challenging but vital aspect of clinical practice. Torque teno virus load (TTVL) was shown to reflect immune competence in KTRs, with low TTVL linked to an elevated risk for rejections and high TTVL associated with infections in the first year post-transplantation. Yet, little is known about the dynamics of TTVL after the first year following transplantation and how TTVL changes with respect to short-term modifications in immunosuppressive therapy. Therefore, we quantified TTVL in 106 KTRs with 108 clinically indicated biopsies, including 65 biopsies performed >12 months post-transplantation, and correlated TTVL to histopathology. In addition, TTVL was quantified at 7, 30, and 90 days post-biopsy to evaluate how TTVL was affected by changes in immunosuppression resulting from interventions based on histopathological reporting. TTVL was highest in patients biopsied between 1 and 12 months post-transplantation (N = 23, median 2.98 × 107 c/mL) compared with those biopsied within 30 days (N = 20, median 7.35 × 103 c/mL) and > 1 year post-transplantation (N = 65, median 1.41 × 104 c/mL; p < 0.001 for both). Patients with BK virus-associated nephropathy (BKVAN) had significantly higher TTVL than patients with rejection (p < 0.01) or other pathologies (p < 0.001). When converted from mycophenolic acid to a mTOR inhibitor following the diagnosis of BKVAN, TTVL decreased significantly between biopsy and 30 and 90 days post-biopsy (p < 0.01 for both). In KTR with high-dose corticosteroid pulse therapy for rejection, TTVL increased significantly between biopsy and 30 and 90 days post-biopsy (p < 0.05 and p < 0.01, respectively). Of note, no significant changes were seen in TTVL within 7 days of changes in immunosuppressive therapy. Additionally, TTVL varied considerably with time since transplantation and among individuals, with a significant influence of age and BMI on TTVL (p < 0.05 for all). In conclusion, our findings indicate that TTVL reflects changes in immunosuppressive therapy, even in the later stages of post-transplantation. To guide immunosuppressive therapy based on TTVL, one should consider inter- and intraindividual variations, as well as potential confounding factors.

Characteristics of COVID-19 Disease in Renal Transplant Recipients

Background and Objectives: Kidney transplant recipients are at risk of developing more severe forms of COVID-19 infection. The aim of this study was to compare the clinical course of COVID-19 infection among kidney transplant patients and a control group. Materials and Methods: We examined 150 patients hospitalized with COVID-19 infection. Patients were divided into study (kidney transplant recipients, n = 53) and control (without a history of kidney transplantation, n = 97) groups. Demographics, clinical characteristics, treatment data, and clinical outcomes were assessed. Results: The median patient age was 56.0 (46.0-64.0) years, and seventy-seven patients (51.3%) were men. The median Charlson comorbidity index was higher in the study group (3.0 vs. 2.0, p < 0.001). There was a higher incidence of hypoxemia in the control group upon arrival (52.6% vs. 22.6%, p = 0.001) and a higher NEWS index median (2.0 vs. 1.0 points, p = 0.009) and incidence of pneumonia during hospitalization (88.7% vs. 73.6%, p = 0.023). In the study group, there were more cases of mild (26.4% vs. 11.3%, p = 0.023) and critically severe forms of COVID-19 infection (26.4% vs. 3.1%, p < 0.001), kidney failure was more prevalent (34.0% vs. 1.0%, p < 0.001), and a greater number of patients were transferred to the intensive care unit (22.6% vs. 3.1%, p < 0.001) and died (18.9% vs. 1.0%, p < 0.001). Multivariable analysis revealed that treatment in the intensive care unit correlated with a higher mortality rate than transplantation itself (HR = 20.71, 95% CI 2.01-213.33, p = 0.011). Conclusions: The course of the COVID-19 disease in kidney transplant recipients is heterogeneous and can be more severe than in the general population. Even though patients may be hospitalized with fewer symptoms, complications and death are more likely to occur.

Massive Airway Bleeding Caused by Pulmonary Strongyloidiasis in a Patient with a Transplanted Kidney

Introduction

We report a fatal case of massive airway bleeding caused by pulmonary strongyloidiasis in a patient with a transplanted kidney.

Case Presentation

A 47-year-old male, regularly taking immunosuppressants post-kidney transplant, visited our hospital with symptoms of abdominal bloating, nausea, and emesis persisting for three days. After hospitalization, he developed a cough, hemoptysis, and respiratory failure. Sputum analysis confirmed an infestation with Strongyloides stercoralis. Despite receiving albendazole therapy and bronchoscopic management for bronchial hemorrhage, the patient ultimately died due to acute respiratory and circulatory collapse triggered by severe airway bleeding.

Conclusion

Patients undergoing immunosuppressive therapy following kidney transplantation are at increased risk for disseminated strongyloidiasis. Consequently, infectious disease screening prior to transplantation, along with essential preventive pharmacotherapy, is of paramount importance.

Risk of herpes simplex virus infection in solid organ transplant recipients: A population-based cross-sectional study

BACKGROUND

Herpes simplex virus (HSV) is an opportunistic infection antigen in solid organ transplant (SOT) recipients. However, this phenomenon has received limited attention from epidemiologists. Our study aims to determine the HSV infection risk in SOT recipients.

METHODS

This was a nationwide population-based cross-sectional study based on the National Health Insurance Research Database from 2002 to 2015. We used propensity score matching to avoid selection bias and analyzed the association between HSV infection and SOT recipients with multiple logistic regression analysis.

RESULTS

At a 3-year follow-up, SOT recipients had a higher risk of developing HSV, with an adjusted odds ratio (aOR) of 3.28 (95% confidence interval (CI), 2.51-4.29). Moreover, at 6-month, 1-year, and 2-year follow-ups, SOT recipients also had an increased risk of HSV than general patients with aORs of 3.85 (95% CI, 2.29-6.49), 4.27 (95% CI, 2.86-6.36), and 3.73 (95% CI, 2.74-5.08), respectively. In the subgroup analysis, lung transplant recipients (aOR = 8.01; 95% CI, 2.39-26.88) exhibited a significantly higher chance of HSV among SOT recipients, followed by kidney transplant recipients (aOR = 3.33; 95% CI, 2.11-5.25) and liver transplant recipients (aOR = 3.15; 95% CI, 2.28-4.34).

CONCLUSION

HSV can develop at any time after organ transplantation. SOT recipients had a higher risk of HSV infection than the general population at 6 months, 1 year, 2 years, and 3 years after transplantation, with the highest chance at 1 year after. In addition, the patients who underwent lung transplantion were at higher risk for HSV infection than liver or kidney transplant recipients.

Epitope-based precision immunotherapy of Type 1 diabetes

Antigen-specific immunotherapies (ASITs) address important clinical needs in treating autoimmune diseases. However, Type 1 diabetes is a heterogeneous disease wherein patient characteristics influence responsiveness to ASITs. Targeting not only disease-relevant T cell populations, but also specific groups of patients using precision medicine is a new goal toward achieving effective treatment. HLA-restricted peptides provide advantages over protein as antigens, however, methods for profiling antigen-specific T cells need to improve in sensitivity, depth, and throughput to facilitate epitope selection. Delivery approaches are highly diverse, illustrating the many ways relevant antigen-presenting cell populations and anatomical locations can be targeted for tolerance induction. The role of persistence of antigen presentation in promoting durable antigen-specific tolerance requires further investigation. Based on the outcome of ASIT trials, the field is moving toward using patient-specific variations to improve efficacy, but challenges still lie on the path to delivering more effective and safer treatment to the T1D patient population.

Prevention and Management of Infections in Lung Transplant Recipients

Anti-rejection medications are essential in preventing organ rejection amongst solid organ transplant recipients; however, these agents also cause profound immunosuppression, predisposing lung transplant recipients (LTRs) to infectious complications. The timely management including prevention, diagnosis, and treatment of such infectious complications is vital to prevent significant morbidity and mortality in solid organ transplant recipients and allograft dysfunction. LTRs are inundated with microbes that may be recognized as commensals in hosts with intact immune systems. Bacterial infections are the most common ones, followed by viral pathogens. Indications of a brewing infectious process may be subtle. Hence, the importance of adapting vigilance around isolated hints through symptomatology and signs is pivotal. Signals to suggest an infectious process, such as fever and leukocytosis, may be dampened by immunosuppressive agents. One must also be vigilant about drug interactions of antibiotics and immunosuppressive agents. Treatment of infections can become challenging, as antimicrobials can interact with immunosuppressive agents, and antimicrobial resistance can surge under antimicrobial pressure. Transplant infectious disease physicians work in concert with transplant teams to obtain specimens for diagnostic testing and follow through with source control when possible. This heavily impacts medical decisions and fosters a multidisciplinary approach in management. Furthermore, the reduction of immunosuppression, although it augments the risk of allograft rejection, is as crucial as the initiation of appropriate antimicrobials when it comes to the management of infections.

Risk stratification of renal transplant recipients using routine parameters: Implication of learning from SARS-CoV-2 into transplant follow-up program

BACKGROUND

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is a global pandemic that is associated with a high risk of morbidity and mortality among recipients of solid organ transplantation. In the course of acute SARS-CoV-2 infection, various laboratory markers have been identified as predictors for high risk of mortality.

AIM

To risk stratify renal transplant recipients (RTxR) using general demographic parameters, comorbidities and routine laboratory markers for the severity of the disease and its outcomes. We believe that learning about these routinely moni tored parameters can help us plan better strategies for the RTxR follow-up program.

METHODS

This present study includes RTxR who acquired SARS-CoV-2 infection from March 2020 to February 2021. We recorded the basic demographics, comorbidities and routine laboratory markers. We investigated the impact of SARS-CoV-2 infection on RTxRs and risk-stratified the progression of disease severity and outcomes in terms of recovery or mortality.

RESULTS

From 505 RTxRs in our renal transplant follow-up program, 29 (7.75%) RTxRs had PCR-positive SARS-CoV-2 infection. We recorded 8 deaths from SARS-CoV-2 infection giving an overall mortality rate of 1.6% but a significant 27.6% mortality in SARS-CoV-2 positive recipients. Age more than 68 years, non-Caucasian ethnicity and male gender were associated with a significant drop in survival probability; P ≤ 0.001. < 0.001 and < 0.0001 respectively. 87.5% of the deceased were diabetic; P ≤ 0.0.0001. Estimated glomerular filtration rate of less than 26 mL/min/1.73 m2, serum albumin less than 20 g/L, Hemoglobin less than 9.6 g/L and serum calcium less than 1.70 mmol/L were all associated with significantly increased risk of mortality; P = 0.0128, < 0.001, < 0.0001 and 0.0061 respectively.

CONCLUSION

This study has identified some routinely used modifiable parameters in predicting a higher risk of mortality and morbidity. This knowledge can be used in RTxR follow-up programs by addressing these parameters early to help reduce the morbidity and mortality in RTxRs.

EBV Reactivation in Transplant Recipients following SARS-CoV-2 Infection: A Retrospective Study

Reactivation and primary infection with a high Epstein Barr Virus (EBV) DNA level in kidney transplant patients could cause severe complications, including the development of Post-Transplantation Lymphoproliferative Disease (PTLD). While in the general population the reactivation of EBV after SARS-CoV-2 infection has been reported, very few data are available in transplant recipients. Our retrospective study aimed to evaluate a possible EBV reactivation in kidney transplant patients following SARS-CoV-2 infection and a possible impairment of the immune system. In addition, the effects of changes in immunosuppressive therapy on EBV DNA reactivation and vaccination were also evaluated. A total of 166 kidney transplant patients followed at the Kidney-Pancreas Transplant Ambulatory Nephrology Unit at Padova University Hospital were retrospectively considered for an observation period of 6 months from January 2020 to April 2023. EBV DNA level was measured by Rt-PCR and evaluated 6 months before and after SARS-CoV-2 infection. Patients' serological states were established via quantification of anti-VCA and anti-EBNA (chemiluminescence). Patients' immune systems were characterized by CD4+/CD8+ lymphocyte ratio (flow cytometry). EBV DNA was reactivated in 50% of the 166 patients with COVID-19 who completed the study. Older patients with more severe forms of COVID-19 had higher EBV reactivation (p < 0.05). EBV reactivation significantly increased in patients with severe SARS-CoV-2 infection requiring hospitalization compared to patients managed at home (p < 0.001). CD4+/CD8+ lymphocyte ratio was reduced in patients with a younger age of transplant (p < 0.01) and on a higher dose of steroids (p < 0.01). The results of our study confirm the role of immunodepression, especially in recent transplant patients and those on high steroids, in EBV reactivation. These results combined with the few available in the literature might contribute to providing an optimal management of immunosuppressive treatment for these patients in order to obtain an immune state unfavorable to the activation of latent viruses, including EBV.

Modulatory immune responses in fungal infection associated with organ transplant - advancements, management, and challenges

Organ transplantation stands as a pivotal achievement in modern medicine, offering hope to individuals with end-stage organ diseases. Advancements in immunology led to improved organ transplant survival through the development of immunosuppressants, but this heightened susceptibility to fungal infections with nonspecific symptoms in recipients. This review aims to establish an intricate balance between immune responses and fungal infections in organ transplant recipients. It explores the fundamental immune mechanisms, recent advances in immune response dynamics, and strategies for immune modulation, encompassing responses to fungal infections, immunomodulatory approaches, diagnostics, treatment challenges, and management. Early diagnosis of fungal infections in transplant patients is emphasized with the understanding that innate immune responses could potentially reduce immunosuppression and promise efficient and safe immuno-modulating treatments. Advances in fungal research and genetic influences on immune-fungal interactions are underscored, as well as the potential of single-cell technologies integrated with machine learning for biomarker discovery. This review provides a snapshot of the complex interplay between immune responses and fungal infections in organ transplantation and underscores key research directions.

Emerging approaches to induce immune tolerance to therapeutic proteins

Immunogenicity affects the safety and efficacy of therapeutic proteins. This review is focused on approaches for inducing immunological tolerance to circumvent the immunogenicity of therapeutic proteins in the clinic. The few immune tolerance strategies that are used in the clinic tend to be inefficient and expensive and typically involve global immunosuppression, putting patients at risk of infections. The hallmark of a desirable immune tolerance regimen is the specific alleviation of immune responses to the therapeutic protein. In the past decade, proof-of-principle studies have demonstrated that emerging technologies, including nanoparticle-based delivery of immunomodulators, cellular targeting and depletion, cellular engineering, gene therapy, and gene editing, can be leveraged to promote tolerance to therapeutic proteins. We discuss the potential of these novel approaches and the barriers that need to be overcome for translation into the clinic.

Herpes Virus Infection in Lung Transplantation: Diagnosis, Treatment and Prevention Strategies

Lung transplantation is an ultimate treatment option for some end-stage lung diseases; due to the intense immunosuppression needed to reduce the risk of developing acute and chronic allograft failure, infectious complications are highly incident. Viral infections represent nearly 30% of all infectious complications, with herpes viruses playing an important role in the development of acute and chronic diseases. Among them, cytomegalovirus (CMV) is a major cause of morbidity and mortality, being associated with an increased risk of chronic lung allograft failure. Epstein-Barr virus (EBV) is associated with transformation of infected B cells with the development of post-transplantation lymphoproliferative disorders (PTLDs). Similarly, herpes simplex virus (HSV), varicella zoster virus and human herpesviruses 6 and 7 can also be responsible for acute manifestations in lung transplant patients. During these last years, new, highly sensitive and specific diagnostic tests have been developed, and preventive and prophylactic strategies have been studied aiming to reduce and prevent the incidence of these viral infections. In this narrative review, we explore epidemiology, diagnosis and treatment options for more frequent herpes virus infections in lung transplant patients.

Impact of Infection-Related Immunosuppressant Reduction on Kidney Transplant Outcomes: A Retrospective Study Considering the Temporal Dynamics of Immunosuppressive Requirements

Immunosuppressant reduction (ISR) is a common treatment for kidney transplant recipients experiencing infections, but its impacts on kidney transplant outcomes remains unclear. This retrospective single-center study included 300 patients who underwent kidney transplantation between January 2017 and April 2020. The post-transplant timeline was divided into four distinct phases: ≤1 month, 2-6 months, 7-12 months, and >12 months. Patients were categorized based on the presence of clinically relevant infections and whether they received ISR. Significant differences were observed in the spectrum of clinically relevant infections across the post-transplant phases. During the ≤1 month phase, primary infections were associated surgical operation, such as urinary tract infections involving Enterococcus spp. and Candida spp. Cytomegalovirus and BK polyomavirus (BKPyV) infections increased during the 2-6 months and 7-12 months periods. Approximately one-third of patients experienced ISR due to infection, with BKPyV infections being the primary causes. Recipients who experienced their first ISR due to infection between 2-6 months and 7-12 months had worse graft survival comparing with patients without any infections. ISR due to infections between 2 and 6 months was associated with a higher risk of rejection. Tailored ISR strategies should be developed according to temporal dynamics of immunosuppressive intensity to prevent rejection.

Infections in the first year of living related kidney transplantation in a young transplant cohort

BACKGROUND

Infection after a kidney transplant is a serious cause of morbidity and mortality. Weighing the risks and benefits of immunosuppression is of paramount importance for patient wellbeing and transplant survival.

METHODS

This is a prospective observational study exploring the variety of bacterial, viral and fungal infections occurring within the first year of living related kidney transplantation in a young transplant cohort. Fifty-one kidney transplant recipients (KTR) between the age of 18 and 45 who had a kidney transplant between Jan 2020 and Jan 2022 were enrolled and followed up for one year. Primary outcome was the occurrence of infection.

RESULTS

Twenty-four patients (47%) recorded a collective 33 episodes of infection. Seven patients had repeated infections and 17 had single infections. Twenty-seven patients had an uneventful year with no infections recorded. Commonest infection was lower urinary tract infection (UTI) (27.3%) followed by SARS-COV2 and Herpes Zoster (15.2%). The commonest pathogens causing lower UTI were Escherichia coli (E coli) (21.2%) and Klebsiella (18.2%). Median Tacrolimus level was (7.8) ng/ml in KTR with infection and (8.95) ng/ml in KTR without infection, p = 0.21. Median Haemoglobin (IQR) was (10.2) g/dl (7.8-14) gm/dl in KTR with infection compared to (10.8) g/dl (7.3-15.3) in KTR without infection odds ratio (OR) = 0.78, confidence interval (CI) (0.5-1.1); p = 0.16.In KTR with infection 25% had donors above the age of 60 compared to 11% in KTR without infection ( OR 2.6,CI (0.5-12), p = 0.2). Post transplant diabetes (PTDM) occurred in (25%) in KTR with infection compared to those without, but that was not statistically significant p = 0. 365.In KTR without infection, 59.3% had a preemptive transplant compared to 20.8% in the group with infection (OR = 0.18; 95% CI: 0.052-0.631; p = 0.007). Median tacrolimus was 7.8 ng/ml in KTR with single infection compared to 7.7 ng/ml in KTR with repeated infections.

CONCLUSION

This study shows that the commonest infection occurring in the first-year post kidney transplant was lower urinary tract infection followed by SARS-COV2 and Herpes Zoster. There was no difference in trough tacrolimus or haemoglobin levels between KTR who developed infection with those who did not.

Current practices and attitudes of dental practitioners regarding the provision of dental treatment for patients with solid organ transplants

BACKGROUND

Solid organ transplant provides a lifeline for people with end stage organ failure. Each year the number of individuals in receipt of a solid organ transplant is increasing. Prevention of post-transplant sepsis and infection are critical for transplant success. The oral cavity contains more than 700 different species of bacteria and is a potential reservoir for disease causing pathogens. Prior to undergoing solid organ transplant, individuals must receive a certification of dental health from a dental practitioner. There are currently no guidelines or protocols for dental practitioners to follow when certifying a patient as dentally fit. This allows for a wide variation of the term 'dentally fit'. This survey was conducted as part of a larger study assessing the oral health of adults with cystic fibrosis ongoing in Cork University Dental School and Hospital. The aim of the study was to ascertain current practices and attitudes of dental practitioners regarding the provision of dental treatment pre and post solid organ transplantation.

METHODS

An anonymous cross sectional survey of dental practitioners in Ireland was conducted.

RESULTS

The data collected showed a wide variation in the provision of treatment for patient undergoing or in receipt of a solid organ transplant.

CONCLUSION

It demonstrates a need for further research to be conducted to ascertain the full impact solid organ transplant has on oral health, so that guidelines can be developed to aid both dental and medical professionals in the treatment of this vulnerable cohort.

Herpes Virus Infections in Kidney Transplant Patients (HINT) - a prospective observational cohort study

BACKGROUND

Kidney transplant recipients receive maintenance immunosuppressive therapy to avoid allograft rejection resulting in increased risk of infections and infection-related morbidity and mortality. Approximately 98% of adults are infected with varicella zoster virus, which upon reactivation causes herpes zoster. The incidence of herpes zoster is higher in kidney transplant recipients than in immunocompetent individuals, and kidney transplant recipients are at increased risk of severe herpes zoster-associated disease. Vaccination with adjuvanted recombinant glycoprotein E subunit herpes zoster vaccine (RZV) prevents herpes zoster in older adults with excellent efficacy (90%), and vaccination of kidney transplant candidates is recommended in Danish and international guidelines. However, the robustness and duration of immune responses after RZV vaccination, as well as the optimal timing of vaccination in relation to transplantation remain unanswered questions. Thus, the aim of this study is to characterize the immune response to RZV vaccination in kidney transplant candidates and recipients at different timepoints before and after transplantation.

METHODS

The Herpes Virus Infections in Kidney Transplant Patients (HINT) study is a prospective observational cohort study. The study will include kidney transplant candidates on the waiting list for transplantation (n = 375) and kidney transplant recipients transplanted since January 1, 2019 (n = 500) from all Danish kidney transplant centers who are offered a RZV vaccine as routine care. Participants are followed with repeated blood sampling until 12 months after inclusion. In the case of transplantation or herpes zoster disease, additional blood samples will be collected until 12 months after transplantation. The immune response will be characterized by immunophenotyping and functional characterization of varicella zoster virus-specific T cells, by detection of anti-glycoprotein E antibodies, and by measuring cytokine profiles.

DISCUSSION

The study will provide new knowledge on the immune response to RZV vaccination in kidney transplant candidates and recipients and the robustness and duration of the response, potentially enhancing preventive strategies against herpes zoster in a population at increased risk.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05604911).

Investigating infectious outcomes in adult patients undergoing solid organ transplantation: A retrospective single-center experience, Paris, France

OBJECTIVES

This study described the demographic characteristics, clinical presentation, treatment, and outcomes of solid organ transplant recipients who were admitted to our center for infection. It also determined factors associated with a poor outcome, and compares early and late period infections.

METHODS

In this retrospective observational study, conducted at a tertiary care center in France between October 2017 and March 2019, infectious outcomes of patients with solid organ transplant where studied.

RESULTS

A total of 104 patients were included with 158 hospitalizations for infection. Among these 104 patients, 71 (68%) were men. The median age was 59 years old. The most common symptoms on admission were fever (66%) and chills (31%). Lower respiratory tract infections were the most common diagnosis (71/158 hospitalizations). Urinary tract infections were frequently seen in kidney transplant recipients (25/60 hospitalizations). One or more infectious agents were isolated for 113 hospitalizations (72%): 70 bacteria, 36 viruses and 10 fungi, with predominance of gram-negative bacilli (53 cases) of which 13 were multidrug-resistant. The most frequently used antibiotics were third generation cephalosporins (40 cases), followed by piperacillin-tazobactam (26 cases). We note that 25 infections (16%) occurred during the first 6 months (early post-transplant period). Patients admitted during the early post-transplant period were more often on immunosuppressive treatment with prednisone (25/25 VS 106/133) (p = 0.01), mycophenolic acid (22/25 VS 86/133) (p = 0.03), presented for an urinary tract infection (10/25 VS 25/133) (p = 0.04) or a bacterial infection (17/25 VS 53/133) (p = 0.01). Patients with later infection had more comorbidities (57/83 VS 9/21) (p = 0.03), cancer (19/83 VS 0/21) (p = 0.04) or were on treatment with everolimus (46/133 VS 0/25) (p = 0.001). During 31 hospitalizations (20%), patients presented with a serious infection requiring intensive care (n = 26; 16%) or leading to death (n = 7; 4%). Bacteremia, pulmonary and cardiac complications were the main risk factors associated with poor outcome.

CONCLUSION

Infections pose a significant challenge in the care of solid organ transplant patients, particularly those with comorbidities and intensive immunosuppression. This underscores the crucial importance of continuous surveillance and epidemiologic monitoring within this patient population.

Evolving challenges with long-term care of liver transplant recipients

The number of liver transplants (LT) performed worldwide continues to rise, and LT recipients are living longer post-transplant. This has led to an increasing number of LT recipients requiring lifelong care. Optimal care post-LT requires careful attention to both the allograft and systemic issues that are more common after organ transplantation. Common causes of allograft dysfunction include rejection, biliary complications, and primary disease recurrence. While immunosuppression prevents rejection and reduces incidences of some primary disease recurrence, it has detrimental systemic effects. Most commonly, these include increased incidences of metabolic syndrome, various malignancies, and infections. Therefore, it is of utmost importance to optimize immunosuppression regimens to prevent allograft dysfunction while also decreasing the risk of systemic complications. Institutional protocols to screen for systemic disease and heightened clinical suspicion also play an important role in providing optimal long-term post-LT care. In this review, we discuss these common complications of LT as well as unique considerations when caring for LT recipients in the years after transplant.

Proximity-dependent mapping of the HCMV US28 interactome identifies RhoGEF signaling as a requirement for efficient viral reactivation

Human cytomegalovirus (HCMV) encodes multiple putative G protein-coupled receptors (GPCRs). US28 functions as a viral chemokine receptor and is expressed during both latent and lytic phases of virus infection. US28 actively promotes cellular migration, transformation, and plays a major role in mediating viral latency and reactivation; however, knowledge about the interaction partners involved in these processes is still incomplete. Herein, we utilized a proximity-dependent biotinylating enzyme (TurboID) to characterize the US28 interactome when expressed in isolation, and during both latent (CD34+ hematopoietic progenitor cells) and lytic (fibroblasts) HCMV infection. Our analyses indicate that the US28 signalosome converges with RhoA and EGFR signal transduction pathways, sharing multiple mediators that are major actors in processes such as cellular proliferation and differentiation. Integral members of the US28 signaling complex were validated in functional assays by immunoblot and small-molecule inhibitors. Importantly, we identified RhoGEFs as key US28 signaling intermediaries. In vitro latency and reactivation assays utilizing primary CD34+ hematopoietic progenitor cells (HPCs) treated with the small-molecule inhibitors Rhosin or Y16 indicated that US28 -RhoGEF interactions are required for efficient viral reactivation. These findings were recapitulated in vivo using a humanized mouse model where inhibition of RhoGEFs resulted in a failure of the virus to reactivate. Together, our data identifies multiple new proteins in the US28 interactome that play major roles in viral latency and reactivation, highlights the utility of proximity-sensor labeling to characterize protein interactomes, and provides insight into targets for the development of novel anti-HCMV therapeutics.

Vaccination in Kidney Transplant Candidates

Background

Kidney transplant (KT) candidates have historically low immunization rates against recommended vaccines. A retrospective single-center study of contemporary KT candidates was conducted to assess vaccination rates and vaccine uptake.

Methods

All KT candidates ≥18 y evaluated between January 1, 2020, and December 31, 2020, were retrospectively reviewed for history of prior vaccination against tetanus, diphtheria, and pertussis; 13-valent pneumococcal conjugate vaccine; 23-valent pneumococcal polysaccharide vaccine; and recombinant zoster vaccine. Positive hepatitis A IgG total, hepatitis B surface antibody, measles, mumps, rubella, and varicella IgG were assessed as surrogate markers of immunity. Vaccine uptake among vaccine-eligible candidates was also assessed.

Results

Among 150 KT candidates, the rate of prior vaccination against tetanus, diphtheria, and pertussis; 13-valent pneumococcal conjugate vaccine; 23-valent pneumococcal polysaccharide vaccine; and recombinant zoster vaccine (latter among patients ≥50 y) was found to be as low as 11%. Hepatitis A IgG total, hepatitis B surface antibody, measles, mumps, rubella, and varicella IgG seropositivity rates were 30%, 66%, 88%, 78%, 90%, and 96%, respectively. Only 7 (5%) of 150 patients had complete immunization or seropositivity. Five (3%) of 143 vaccine-eligible patients declined vaccination. Hepatitis A vaccine declination was relatively common with 15 (16%) of 94 vaccine-eligible patients declining it.

Conclusions

KT candidates have low baseline rates of prior immunization/seropositivity against most recommended vaccines. Overall vaccine uptake among eligible candidates was high.

Optimal Perioperative Antimicrobial Management Strategies of Kidney Transplant Recipients Guided by Metagenomic Next-Generation Sequencing of Deceased Donors' Microbiology Samples

Background

There is no consensus on the optimal use of perioperative antibiotics prophylaxis after kidney transplantation, but there is a common trend to limit the duration of antibiotic use worldwide. Metagenomic next-generation sequencing (mNGS) has emerged as a novel technology for pathogen detection in clinical practice due to its noninvasive, rapid, precise and high susceptibility to detect infectious pathogens. However, data are lacking on whether mNGS analyses could be used to detect pathogens and guide anti-infection regimens in kidney transplant donors and recipients.

Methods

We conducted a retrospective study to review all clinic data of mNGS and traditional laboratory methods (TMs) for pathogen detection in kidney transplant recipients and their corresponding deceased donors from August 1, 2021 to October 30, 2022 in our center.

Results

A total of 57 donors and 112 of their corresponding recipients were included. The antimicrobial strategy mainly depended on mNGS results combined with traditional pathogen culture and clinical conditions. The percentages of positive pathogen detected by mNGS in blood, urine, bronchoalveolar lavage fluid (BALF) and preservation fluids (PFs) were 50.9% (29/57), 35.1% (20/57), 84.2% (48/57) and 54.4% (31/57) respectively, and were 24.6% (14/57), 15.8% (9/57), 57.9% (33/57) and 14.1% (8/57) respectively when using TMs. mNGS could detected all of pathogens which were detected by TMs. However, samples with negative TMs testing can be additionally detected as positive by mNGS (15/43 in blood, 11/48 in urine, 15/24 in BALF and 23/49 in PFs). Drug resistance genes were detected in 9 donors by mNGS,which were consistent with 6 donors by TMs. There was only one case of donor-derived infection in this study.

Conclusion

This study showed that it is effective to combine mNGS with traditional pathogen detection methods and clinical features to develop optimal perioperative antimicrobial management strategies for deceased donor kidney transplantation.

Immune monitoring of prevalent kidney transplant recipients using Torque Teno Virus: Protocol for a single-centre prospective cohort study

INTRODUCTION

Kidney transplant recipients (KTRs) suffer from immunosuppression-related adverse events (iRAEs), such as infections and malignancy from chronic immunosuppression, but are also at risk of graft loss from rejection with underimmunosuppression. Biomarkers that predict both iRAEs and rejection while allowing individualisation of immunosuppression exposure are lacking. Although plasma viral DNA levels of torque teno virus (TTV), a widely prevalent, non-pathogenic virus, have been shown to predict both iRAE and rejection in newly transplanted KTRs within the first year after transplant, its role for prevalent KTRs on stable immunosuppression is less clear.This study aims to determine the prognostic value of TTV levels for severe infections (defined as infections requiring hospitalisation) in prevalent KTRs on stable immunosuppression for at least 3 months and compare it against that of other commonly available biomarkers. The study also aims to explore the relationship between TTV levels and factors affecting the 'net state of immunosuppression' as well as other clinical outcomes.

METHODS AND ANALYSIS

This is a single-centre, prospective, observational cohort study of 172 KTRs on stable immunosuppression for more than 3 months. TTV levels will be measured using the TTV R-GENE kit upon recruitment when study subjects are admitted and when kidney allograft biopsies are performed. Subjects will be monitored for iRAEs and rejection for at least 12 months. The relationship between TTV load and clinical outcomes such as severe infections will be analysed and compared against that from other common biomarkers and previously published predictive scores.

ETHICS AND DISSEMINATION

The study was approved by the SingHealth Centralised Institutional Review Board (2023/2170). The results will be presented at conferences and submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05836636.

A quick algorithmic review on management of viral infectious diseases in pediatric solid organ transplant recipients

Pediatric solid organ transplant is a life-saving procedure for children with end-stage organ failure. Viral infections are a common complication following pediatric solid organ transplantation (SOT), which can lead to increased morbidity and mortality. Pediatric solid organ transplant recipients are at an increased risk of viral infections due to their immunosuppressed state. The most commonly encountered viruses include cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), varicella-zoster virus (VZV), adenoviruses, and BK polyomavirus. Prevention strategies include vaccination prior to transplantation, post-transplant prophylaxis with antiviral agents, and preemptive therapy. Treatment options vary depending on the virus and may include antiviral therapy and sometimes immunosuppression modification. This review provides a Quick Algorithmic overview of prevention and treatment strategies for viral infectious diseases in pediatric solid organ transplant recipient.

Renal Transplantation: Immediate and Late Complications

Kidney grafts are the most common transplanted solid organ. To optimize graft survival, radiologists should be familiar with the anatomy and potential complications unique to transplanted kidneys. In addition to being able to recognize the imaging characteristics to diagnose etiologies of kidney graft dysfunction, an understanding of the pathophysiology is a key to narrowing the differential diagnosis. This article provides a summary of the most common complications based on broad categories of type of complication and posttransplant timing.

Reasons for kidney transplant refusal among patients receiving peritoneal dialysis: A qualitative study

BACKGROUND

Even though kidney transplantation has better outcomes compared to dialysis therapies, some patients undergoing peritoneal dialysis (PD) refuse to consider kidney transplantation. Identification of the underlying reason for patient refusal may improve patients' acceptance of kidney transplantation.

AIM

The aim of this study was to describe the reasons given by Iranian PD patients for refusing kidney transplantation.

METHOD

Eighteen patients undergoing PD participated. Data were collected using semi-structured interviews and were analysed using conventional qualitative content analysis.

RESULTS

The analysis leads to the emergence of two categories and six subcategories: negative outcomes of kidney transplantation (financial burden, psychosocial problems and physical complications) and doubtful factors for kidney transplantation (negative attitudes towards kidney transplantation, long waiting time for kidney transplantation and compatibility of PD with daily life). The financial burden and long waiting time for kidney transplantation were the most important factors in the reluctance of kidney transplantation by PD patients.

IMPLICATION FOR PRACTICE

Patients undergoing PD declined kidney transplantation for several reasons, such as financial burden, fear of post-transplantation side effects, long waiting time for kidney transplantation. Reducing the time of kidney transplantation and insurance coverage of transplant costs can change the attitude of PD patients towards transplant.

Immunosuppressive Therapy in Solid Organ Transplantation: Primer for Radiologists and Potential Complications

The availability of effective immunosuppressive medication is primarily responsible for the dramatic improvement in long-term graft survival rates after solid organ transplantation. The commonly used drugs include monoclonal/polyclonal antibodies, corticosteroids, calcineurin inhibitors (cyclosporine and tacrolimus), antimetabolites, mammalian target of rapamycin, and many novel drugs. Prolonged immunosuppression is accompanied by several well-described potentially life-threatening complications. In addition to drug-related side effects, recipients of solid organs are unavoidably at a higher risk for infections and malignancies. Select infections and malignancies in solid organ transplant patients have distinctive imaging findings, and radiologists play a crucial role in the timely diagnosis and management of these conditions.

Outcomes in organ transplants from donors with melanoma: a systematic review

Melanoma transmitted through organ transplantation is an increasingly reported event. Immunosuppression increases the risk of melanoma; however, transmission of malignancy from transplanted organs is a distinct etiology of melanoma occurrence. The risk of transmission of melanoma from an organ donor with melanoma has yet to be determined. The authors aimed to investigate this phenomenon by reviewing the outcomes of patients that received organs from donors with melanoma. A systematic literature review was conducted with emphasis on identifying organ donors with known histories of melanoma and reported information regarding recipients of their organs. The databases PubMed, MEDLINE, Embase, and JBI EBP were searched in January 2023. Search terms included "melanoma," terms for solid organs, "donor," "transplant," "transmission," and their variations as well as terms related to temporal relations. Inclusion criteria were articles that stated outcomes in organ recipients from donors that had a diagnosis of melanoma either pretransplant or postmortem. Reference lists of selected articles were hand searched for further studies. A total of 232 articles were identified from the search parameters. After applying inclusion and exclusion criteria, 13 articles were selected. Hand searching the references of these articles yielded four additional articles. Of the 75 organ recipients that received organs from donors with known melanoma, 43 developed melanoma. While a definitive quantitative risk cannot be ascertained based on our review, the numerous reported cases of melanoma in organ recipients from donors that have melanoma should still be considered by clinicians.