A Case of Primary Renal Allograft Dysfunction Caused by Missed Monoclonal Disease.

We present an unusual etiology of primary renal allograft dysfunction attributed to myeloma cast nephropathy in a patient with no history of multiple myeloma before kidney transplant. The patient, a 54-year-old woman, had been on hemodialysis for 6 months before transplant for presumed diabetic nephropathy; she developed graft dysfunction immediately after transplant. Graft biopsy specimens were consistent with myeloma cast nephropathy, and she was treated with bortezomib, cyclophosphamide, and dexamethasone. She achieved a complete hematological response and regained excellent graft function 3 months after transplant. The patient then received autologous stem cell transplant 8 months after kidney transplant. To our knowledge, this is the second report of a successful graft outcome after chemotherapy and the first report treated with autologous stem cell transplantation after remission of monoclonal disease.

Donor Fractions of Cell-Free DNA Are Elevated During CLAD But Not During Infectious Complications After Lung Transplantation.

During the last few years, cell-free DNA (cfDNA) has emerged as a possible non-invasive biomarker for prediction of complications after lung transplantation. We previously published a proof-of-concept study using a digital droplet polymerase chain reaction (ddPCR)-based method for detection of cfDNA. In the current study, we aimed to further evaluate the potential clinical usefulness of detecting chronic lung allograft dysfunction (CLAD) using three different ddPCR applications measuring and calculating the donor fraction (DF) of cfDNA as well as one method using the absolute amount of donor-derived cfDNA. We analyzed 246 serum samples collected from 26 lung transplant recipients. Nine of the patients had ongoing CLAD at some point during follow-up. All four methods showed statistically significant elevation of the measured variable in the CLAD samples compared to the non-CLAD samples. The results support the use of ddPCR-detected cfDNA as a potential biomarker for prediction of CLAD. These findings need to be validated in a subsequent prospective study.

Comparison of Prognosis for Lung Transplantation between Older and Younger Donors: A Systematic Review and Meta-Analysis Based on Cohort Studies.

PURPOSE: This meta-analysis aimed to compare the prognosis of lung transplantation recipients based on donor age. METHODS: A detailed search was performed in PubMed, Embase, Web of Science, and the Cochrane Library for cohort studies on lung transplantation. The prognosis of lung transplant recipients was investigated based on the donor age, with the primary outcomes being 1-year overall survival (OS), 3-year OS, 5-year OS, and 5-year chronic lung allograft dysfunction (CLAD)-free survival. RESULTS: This meta-analysis included 10 cohort studies. Among the short-term outcomes, the older donor group demonstrated no significant difference from the young donor group in primary graft dysfunction within 72 hours, use of extracorporeal membrane oxygenation, length of ventilator use, and intensive care unit hours. However, a longer hospital stay was associated with the older donor group. In terms of long-term outcomes, no difference was found between the two groups in 1-year OS, 3-year OS, and 5-year OS. Notably, patients with older donors exhibited a superior 5-year CLAD-free survival. CONCLUSIONS: The results of this meta-analysis indicate that older donors are not inferior to younger donors in terms of long-term and short-term recipient outcomes. Lung transplantation using older donors is a potential therapeutic option after rigorous evaluation.

Prognosis of Lung Transplantation in Patients with Acute Exacerbations of Interstitial Lung Disease: A Meta-Analysis Based on Cohort Studies.

PURPOSE: This meta-analysis aimed to examine the prognosis of patients with acute exacerbation of interstitial lung disease (AE-ILD) treated with lung transplantation compared to those with stable interstitial lung disease (ILD). METHODS: We conducted a detailed search in PubMed, Embase, Web of Science, and the Cochrane Library, with the primary outcomes being overall survival (OS), acute cellular rejection (ACR), primary graft dysfunction (PGD), and length of stay (LOS). RESULTS: Five cohort studies were included in this meta-analysis, with 183 patients enrolled in the AE-ILD group and 337 patients in the stable-ILD group. The results showed that in regard to perioperative outcomes, the AE-ILD group did not differ from the stable-ILD group in the incidence of ACR (relative risks [RR] = 0.34, p = 0.44) and the incidence of PGD Ⅲ (RR = 0.53, p = 0.43), but had a longer LOS (mean difference = 9.15, p = 0.02). Regarding prognosis, the two also did not differ in 90-day OS (RR = 0.97, p = 0.59), 1-year OS (RR = 1.05, p = 0.66), and 3-year OS (RR = 0.91, p = 0.76). CONCLUSION: Our study concluded that the efficacy of lung transplantation in patients with AE-ILD is not inferior to that of patients with stable ILD. Lung transplantation is one of the potential treatments for patients with AE-ILD.

IRF1 and IL1A associated with PANoptosis serve as potential immune signatures for lung ischemia reperfusion injury following lung transplantation.

BACKGROUND: Lung ischemia reperfusion injury (IRI) is the principal cause of primary graft dysfunction (PGD) after lung transplantation, affecting short-term and long-term mortality post-transplantation. PANoptosis, a newly identified form of regulated cell death involving apoptosis, necroptosis, and pyroptosis, is now considered a possible cause of organ damage and IRI. However, the specific role of PANoptosis to the development of lung IRI following lung transplantation is still not fully understood. METHODS: In this study, we identified differentially expressed genes (DEGs) by analyzing the gene expression data from the GEO database related to lung IRI following lung transplantation. PANoptosis-IRI DEGs were determined based on the intersection of PANoptosis-related genes and screened DEGs. Hub genes associated with lung IRI were further screened using Lasso regression and the SVM-RFE algorithm. Additionally, the Cibersort algorithm was employed to assess immune cell infiltration and investigate the interaction between immune cells and hub genes. The upstream miRNAs that may regulate hub genes and compounds that may interact with hub genes were also analyzed. Moreover, an external dataset was utilized to validate the differential expression analysis of hub genes. Finally, the expressions of hub genes were ultimately confirmed using quantitative real-time PCR, western blotting, and immunohistochemistry in both animal models of lung IRI and lung transplant patients. RESULTS: PANoptosis-related genes, specifically interferon regulatory factor 1 (IRF1) and interleukin 1 alpha (IL1A), have been identified as potential biomarkers for lung IRI following lung transplantation. In mouse models of lung IRI, both the mRNA and protein expression levels of IRF1 and IL1A were significantly elevated in lung tissues of the IRI group compared to the control group. Moreover, lung transplant recipients exhibited significantly higher protein levels of IRF1 and IL1A in PBMCs when compared to healthy controls. Patients who experienced PGD showed elevated levels of IRF1 and IL1A proteins in their blood samples. Furthermore, in patients undergoing lung transplantation, the protein levels of IRF1 and IL1A were notably increased in peripheral blood mononuclear cells (PBMCs) compared to healthy controls. In addition, patients who developed primary graft dysfunction (PGD) exhibited even higher protein levels of IRF1 and IL1A than those without PGD. Furthermore, PANoptosis was observed in the lung tissues of mouse models of lung IRI and in the PBMCs of patients who underwent lung transplantation. CONCLUSIONS: Our research identified IRF1 and IL1A as biomarkers associated with PANoptosis in lung IRI, suggesting their potential utility as targets for diagnosing and therapeutically intervening in lung IRI and PGD following lung transplantation.

Primary graft dysfunction in heart transplantation: the challenge to survival.

Primary graft dysfunction (PGD) is a life-threatening clinical condition with a high mortality rate, presenting as left, right, or biventricular dysfunction within the initial 24 h following heart transplantation, in the absence of a discernible secondary cause. Given its intricate nature, definitive definition and diagnosis of PGD continues to pose a challenge. The pathophysiology of PGD encompasses numerous underlying mechanisms, some of which remain to be elucidated, including factors like myocardial damage, the release of proinflammatory mediators, and the occurrence of ischemia-reperfusion injury. The dynamic characteristics of both donors and recipients, coupled with the inclination towards marginal lists containing more risk factors, together contribute to the increased incidence of PGD. The augmentation of therapeutic strategies involving mechanical circulatory support accelerates myocardial recovery, thereby significantly contributing to survival. Nonetheless, a universally accepted treatment algorithm for the swift management of this clinical condition, which necessitates immediate intervention upon diagnosis, remains absent. This paper aims to review the existing literature and shed light on how diagnosis, pathophysiology, risk factors, treatment, and perioperative management affect the outcome of PGD.

Early Graft Loss With Suspected Seventh-Day Syndrome Following Pediatric Liver Transplantation.

INTRODUCTION: Allograft dysfunction within the first week posttransplant is an uncommon but known complication following liver transplantation. Seventh-Day Syndrome (7DS) is a rare complication of allograft dysfunction following liver transplantation characterized by the rapid clinical deterioration of a formerly well-functioning allograft within the first week posttransplant. The etiology of 7DS is unknown, and treatment options remain limited. While cases of graft survival have been reported, the risk of mortality remains exceedingly high without urgent retransplantation. METHODS: Patient data was retrospectively analyzed and a literature review performed. RESULTS: We present a unique case of split liver transplantation into two pediatric recipients in which one recipient developed rapidly progressive graft failure approximately 1 week postoperatively requiring urgent retransplantation while the other recipient had an unremarkable postoperative course. Upon clinical manifestation of progressive graft failure, the patient was treated with thymoglobulin, rituximab, intravenous immunoglobulin, and plasmapheresis. Despite this, the patient's clinical status continued to decline and she underwent retransplantation 11 days following her initial liver transplant. CONCLUSION: Seventh-Day Syndrome is a rare complication following liver transplantation that is associated with a high risk of morbidity and mortality. Our case adds to the limited literature on 7DS in children and is the first to report a comparative posttransplant clinical course in two recipients who received split grafts from the same donor.

Donor plasma VEGF-A as a biomarker for myocardial injury and primary graft dysfunction after heart transplantation.

BACKGROUND: Vascular endothelial growth factor (VEGF)-A is an angiogenic and proinflammatory cytokine with profound effects on microvascular permeability and vasodilation. Several processes may induce VEGF-A expression in brain-dead organ donors. However, it remains unclear whether donor VEGF-A is linked to adverse outcomes after heart transplantation. METHODS: We examined plasma VEGF-A levels from 83 heart transplant donors as well as the clinical data of these donors and their respective recipients operated between 2010 and 2016. The donor plasma was analyzed using Luminex-based Multiplex and confirmed with a single-target ELISA. Based on donor VEGF-A plasma levels, the recipients were divided into 3 equal-sized groups (low VEGF <500 ng/liter, n = 28; moderate VEGF 500-3000 ng/liter, n = 28; and high VEGF >3000 ng/liter, n = 27). Biochemical and clinical parameters of myocardial injury as well as heart transplant and kidney function were followed-up for one year, while rejection episodes, development of cardiac allograft vasculopathy, and mortality were monitored for 5 years. RESULTS: Baseline parameters were comparable between the donor groups, except for age, where median ages of 40, 45, and 50 were observed for low, moderate, and high donor plasma VEGF levels groups, respectively, and therefore donor age was included as a confounding factor. High donor plasma VEGF-A levels were associated with pronounced myocardial injury (TnT and TnI), a higher inotrope score, and a higher incidence of primary graft dysfunction in the recipient after heart transplantation. Furthermore, recipients with allografts from donors with high plasma VEGF-A levels had a longer length of stay in the intensive care unit and the hospital, and an increased likelihood for prolonged renal replacement therapy. CONCLUSIONS: Our findings suggest that elevated donor plasma VEGF-A levels were associated with adverse outcomes in heart transplant recipients, particularly in terms of myocardial injury, primary graft dysfunction, and long-term renal complications. Donor VEGF-A may serve as a potential biomarker for predicting these adverse outcomes and identifying extended donor criteria.

Necropsy findings in heart transplant recipients with or without primary graft dysfunction.

BACKGROUND: Primary graft dysfunction (PGD) is the leading cause of death in the first year after heart transplant (HT), but pathophysiology and histology are not completely understood. This study describes and compares morphological findings of hearts of patients with and without PGD. METHODS: We included adult patients submitted to HT in a single center who died within the first 14 days after HT and were submitted to necropsy. Clinical and histological data were recorded retrospectively. All heart slides were reviewed by a blinded pathologist. We categorized patients in two groups (PGD and non-PGD) and compared findings between them. RESULTS: Among 322 HTs, 26 patients were included. Median age was 51.5 years, 57.7% were male, 46.1% had non-ischemic cardiomyopathy, 30.8% Chagas cardiomyopathy and 23% ischemic cardiomyopathy. Eleven patients presented PGD, while 15 patients did not. PGD was severe in 72.7% of cases and moderate in 27.3%. PGD group had longer ischemic time (p=0.08), higher incidence of mechanical circulatory support (p=0.004), lower post-transplant biventricular ejection fraction (p=0.005). However, necropsy findings were similar between groups. Necrosis was detected in 80.7% of all cases (p=0.907 comparing groups), taking ≥ 10% of myocardial area in 46.1% of them, and 4 types of necrosis were found either in patients with and without PGD. CONCLUSION: Cardiac pathological findings were similar in HT patients with or without PGD who died within 14 days after the transplant and necrosis was frequent in both groups, raising the hypothesis necrosis is not the cause of cardiac dysfunction in PGD.

Extreme elevations of donor-derived cell-free DNA increases the risk of chronic lung allograft dysfunction and death, even without clinical manifestations of disease.

BACKGROUND: Lung transplant recipients are traditionally monitored with pulmonary function testing (PFT) and lung biopsy to detect post-transplant complications and guide treatment. Plasma donor-derived cell free DNA (dd-cfDNA) is a novel molecular approach of assessing allograft injury, including subclinical allograft dysfunction. The aim of this study was to determine if episodes of extreme molecular injury (EMI) in lung transplant recipients increases the risk of chronic lung allograft dysfunction (CLAD) or death. METHODS: This multicenter prospective cohort study included 238 lung transplant recipients. Serial plasma samples were collected for dd-cfDNA measurement by shotgun sequencing. EMI was defined as a dd-cfDNA above the third quartile of levels observed for acute rejection (dd-cfDNA level of ≥5% occurring after 45 days post-transplant). EMI was categorized as Secondary if associated with co-existing acute rejection, infection or PFT decline; or Primary if not associated with these conditions. RESULTS: EMI developed in 16% of patients at a median 343.5 (IQR: 177.3-535.5) days post-transplant. Over 50% of EMI episodes were classified as Primary. EMI was associated with an increased risk of severe CLAD or death (HR: 2.78, 95% CI: 1.26-6.22, p = 0.012). The risk remained consistent for the Primary EMI subgroup (HR: 2.34, 95% CI 1.18-4.85, p = 0.015). Time to first EMI episode was a significant predictor of the likelihood of developing CLAD or death (AUC=0.856, 95% CI=0.805-0.908, p < 0.001). CONCLUSIONS: Episodes of EMI in lung transplant recipients are often isolated and may not be detectable with traditional clinical monitoring approaches. EMI is associated with an increased risk of severe CLAD or death, independent of concomitant transplant complications.

Impact of the New Definition of Pulmonary Hypertension on the Prevalence of Primary Graft Dysfunction in Lung Transplant Recipients.

BACKGROUND & AIM: Pulmonary hypertension (PH) secondary to lung disease (Group-3 PH) is the second leading cause of PH. The role of PH as a risk factor for primary graft dysfunction (PGD) following lung transplant (LT) is controversial. OBJECTIVE: To assess the impact that the new definition of PH had on the prevalence of PH in patients with advanced lung disease-candidate for LT, and its association with the occurrence of PGD. METHOD: A retrospective study was performed in all patients undergoing cardiac catheterisation referred for consideration as candidates to LT in a centre between 1 January 2017 and 31 December 2022. The baseline and haemodynamic characteristics of patients were analysed, along with the occurrence of PGD and post-transplant course in those who ultimately underwent transplantation. RESULTS: A total of 396 patients were included. Based on the new 2022 European Society of Cardiology/European Respiratory Society definitions, as many as 70.7% of patients met PH criteria. Since the introduction of the 2022 definition, a significant reduction was observed in the frequency of severe Group-3 PH (41.1% vs 10.3%; p<0.001), with respect to the 2015 definition. As many as 236 patients underwent transplantation. None of the variables associated with PH was identified as a risk factor for PGD. CONCLUSION: The new classification did not have any impact on the prevalence of PGD after transplantation. These results exclude that any significant differences exist in the baseline characteristics or post-transplant course of patients with Group-3 PH vs unclassified PH.

An integrated proteomics and metabolomics approach to assess graft quality and predict early allograft dysfunction after liver transplantation: a retrospective cohort study.

BACKGROUND: Early allograft dysfunction (EAD) is a common complication after liver transplantation (LT) and is associated with poor prognosis. Graft itself plays a major role in the development of EAD. We aimed to reveal the EAD-specific molecular profiles to assess graft quality and establish EAD predictive models. METHODS: A total of 223 patients who underwent LT were enrolled and divided into training ( n =73) and validation ( n =150) sets. In the training set, proteomics was performed on graft biopsies, together with metabolomics on paired perfusates. Differential expression, enrichment analysis, and protein-protein interaction network were used to identify the key molecules and pathways involved. EAD predictive models were constructed using machine learning and verified in the validation set. RESULTS: A total of 335 proteins were differentially expressed between the EAD and non-EAD groups. These proteins were significantly enriched in triglyceride and glycerophospholipid metabolism, neutrophil degranulation, and the MET-related signaling pathway. The top 12 graft proteins involved in the aforementioned processes were identified, including GPAT1, LPIN3, TGFB1, CD59, and SOS1. Moreover, downstream metabolic products, such as lactate dehydrogenase, interleukin-8, triglycerides, and the phosphatidylcholine/phosphorylethanolamine ratio in the paired perfusate displayed a close relationship with the graft proteins. To predict the occurrence of EAD, an integrated model using perfusate metabolic products and clinical parameters showed areas under the curve of 0.915 and 0.833 for the training and validation sets, respectively. It displayed superior predictive efficacy than that of currently existing models, including donor risk index and D-MELD scores. CONCLUSIONS: We identified novel biomarkers in both grafts and perfusates that could be used to assess graft quality and provide new insights into the etiology of EAD. Herein, we also offer a valid tool for the early prediction of EAD.

The diagnosis and management of chronic lung allograft dysfunction.

PURPOSE OF REVIEW: Chronic lung allograft dysfunction (CLAD) remains a life-threatening complication following lung transplantation. Different CLAD phenotypes have recently been defined, based on the combination of pulmonary function testing and chest computed tomography (CT) scanning and spurred renewed interests in differential diagnosis, risk factors and management of CLAD. RECENT FINDINGS: Given their crucial importance in the differential diagnosis, we will discuss the latest development in assessing the pulmonary function and chest CT scan, but also their limitations in proper CLAD phenotyping, especially with regards to patients with baseline allograft dysfunction. Since no definitive treatment exists, it remains important to timely identify clinical risk factors, but also to assess the presence of specific patterns or biomarkers in tissue or in broncho alveolar lavage in relation to CLAD (phenotypes). We will provide a comprehensive overview of the latest advances in risk factors and biomarker research in CLAD. Lastly, we will also review novel preventive and curative treatment strategies for CLAD. SUMMARY: Although this knowledge has significantly advanced the field of lung transplantation, more research is warranted because CLAD remains a life-threatening complication for all lung transplant recipients.

Impact of Acute Exacerbation of Idiopathic Pulmonary Fibrosis on Lung Transplant Outcomes.

BACKGROUND: Acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF) are acute, significant respiratory deteriorations in patients with IPF and can lead to increased morbidity and mortality. It remains unclear how AE-IPF impacts lung transplant (LTX) outcomes. METHODS: All adult patients who were listed for LTX between July 2005 and October 2020 at the Loyola University Medical Center with a diagnosis of IPF were included. Pretransplant characteristics and posttransplant outcomes were gathered via retrospective chart review. The primary outcome was short- and long-term survival for patients transplanted during stable IPF versus those with AE-IPF. RESULTS: One hundred fifty-nine patients were included in this study, 17.6% of whom were transplanted during AE-IPF. AE-IPF patients were more likely to have higher oxygen needs pretransplant, have higher lung allocation score, and were more likely to be intubated or be on extracorporeal membrane oxygenation as compared with stable IPF patients. Survival by AE status at transplant did not differ at 90 d or 1 y posttransplantation. There were also no significant differences in rates of severe primary graft dysfunction or acute rejection within 1 y. CONCLUSIONS: Patients with AE-IPF were more likely to have higher oxygenation requirements and higher lung allocation score at the time of LTX than those with stable IPF. Despite this, there were no differences in survival at 90 d, 1 y, or 3 y, or differences in incidence of severe primary graft dysfunction or acute cellular rejection. Transplantation of patients with AE-IPF has clinical outcomes comparable with transplantation of patients with stable IPF. This contrasts with previous studies examining LTX in patients with AE-IPF.

Airway pepsinogen A4 identifies lung transplant recipients with microaspiration and predicts chronic lung allograft dysfunction.

BACKGROUND: Aspiration is a known risk factor for adverse outcomes post-lung transplantation. Airway bile acids are the gold-standard biomarker of aspiration; however, they are released into the duodenum and likely reflect concurrent gastrointestinal dysmotility. Previous studies investigating total airway pepsin have found conflicting results on its relationship with adverse outcomes post-lung transplantation. These studies measured total pepsin and pepsinogen in the airways. Certain pepsinogens are constitutively expressed in the lungs, while others, such as pepsinogen A4 (PGA4), are not. We sought to evaluate the utility of measuring airway PGA4 as a biomarker of aspiration and predictor of adverse outcomes in lung transplant recipients (LTRs) early post-transplant. METHODS: Expression of PGA4 was compared to other pepsinogens in lung tissue. Total pepsin and PGA4 were measured in large airway bronchial washings and compared to preexisting markers of aspiration. Two independent cohorts of LTRs were used to assess the relationship between airway PGA4 and chronic lung allograft dysfunction (CLAD). Changes to airway PGA4 after antireflux surgery were assessed in a third cohort of LTRs. RESULTS: PGA4 was expressed in healthy human stomach but not lung. Airway PGA4, but not total pepsin, was associated with aspiration. Airway PGA4 was associated with an increased risk of CLAD in two independent cohorts of LTRs. Antireflux surgery was associated with reduced airway PGA4. CONCLUSIONS: Airway PGA4 is a marker of aspiration that predicts CLAD in LTRs. Measuring PGA4 at surveillance bronchoscopies can help triage high-risk LTRs for anti-reflux surgery.

Developing machine learning models to predict primary graft dysfunction after lung transplantation.

Primary graft dysfunction (PGD) is the leading cause of morbidity and mortality in the first 30 days after lung transplantation. Risk factors for the development of PGD include donor and recipient characteristics, but how multiple variables interact to impact the development of PGD and how clinicians should consider these in making decisions about donor acceptance remain unclear. This was a single-center retrospective cohort study to develop and evaluate machine learning pipelines to predict the development of PGD grade 3 within the first 72 hours of transplantation using donor and recipient variables that are known at the time of donor offer acceptance. Among 576 bilateral lung recipients, 173 (30%) developed PGD grade 3. The cohort underwent a 75% to 25% train-test split, and lasso regression was used to identify 11 variables for model development. A K-nearest neighbor's model showing the best calibration and performance with relatively small confidence intervals was selected as the final predictive model with an area under the receiver operating characteristics curve of 0.65. Machine learning models can predict the risk for development of PGD grade 3 based on data available at the time of donor offer acceptance. This may improve donor-recipient matching and donor utilization in the future.

Development and validation of primary graft dysfunction predictive algorithm for lung transplant candidates.

BACKGROUND: Primary graft dysfunction (PGD) is the leading cause of early morbidity and mortality after lung transplantation. Accurate prediction of PGD risk could inform donor approaches and perioperative care planning. We sought to develop a clinically useful, generalizable PGD prediction model to aid in transplant decision-making. METHODS: We derived a predictive model in a prospective cohort study of subjects from 2012 to 2018, followed by a single-center external validation. We used regularized (lasso) logistic regression to evaluate the predictive ability of clinically available PGD predictors and developed a user interface for clinical application. Using decision curve analysis, we quantified the net benefit of the model across a range of PGD risk thresholds and assessed model calibration and discrimination. RESULTS: The PGD predictive model included distance from donor hospital to recipient transplant center, recipient age, predicted total lung capacity, lung allocation score (LAS), body mass index, pulmonary artery mean pressure, sex, and indication for transplant; donor age, sex, mechanism of death, and donor smoking status; and interaction terms for LAS and donor distance. The interface allows for real-time assessment of PGD risk for any donor/recipient combination. The model offers decision-making net benefit in the PGD risk range of 10% to 75% in the derivation centers and 2% to 10% in the validation cohort, a range incorporating the incidence in that cohort. CONCLUSION: We developed a clinically useful PGD predictive algorithm across a range of PGD risk thresholds to support transplant decision-making, posttransplant care, and enrich samples for PGD treatment trials.

The role of lung microbiota in primary graft dysfunction in lung transplant recipients.

BACKGROUND: Recent studies have shown that the lung microbiota is altered in critically ill patients and predicts clinical outcomes. Primary graft dysfunction (PGD) is a common complication and a leading cause of death within 1 month of lung transplantation, but the clinical significance of changes in the lung bacterial community during PGD is unclear. The aim of this study was to determine the contribution of the lung microbiota to the development and course of severe PGD. METHODS: We conducted a retrospective study to characterize the lung microbiota of 32 lung transplant patients with combined PGD using next-generation sequencing of bronchoalveolar lavage samples. The relationship between lung flora dysbiosis and lung immunity in PGD was assessed by quantification of alveolar cytokines. The contribution of microbiota characteristics to patient outcomes was assessed by estimating overall survival. RESULTS: Patients diagnosed with PGD grade 3 showed a reduction in alpha diversity, driven by a significant increase in the abundance of the genera Modestobacter, Scardovia and Selenomonas, and a reduction in the proportion of the genera Klebsiella and Oribacterium. Alpha diversity of the lung microbiota in PGD3 patients was negatively correlated with BALF interleukin (IL)-2 (r = -.752, p < .05). In addition, bacterial diversity in the lung microbiota of non-survivors was lower than that of survivors (p = .041). CONCLUSIONS: There is variation in the lung microbiota of PGD grade 3 patients and dysbiosis of the lung microbiota is associated with lung immunity. The lung microbiota has potential in the diagnosis and treatment of PGD grade 3.

The Role of Recipient Thyroid Hormone Supplementation in Primary Graft Dysfunction After Heart Transplantation: A Propensity-Adjusted Analysis.

OBJECTIVES: To investigate whether recipient administration of thyroid hormone (liothyronine [T3]) is associated with reduced rates of primary graft dysfunction (PGD) after orthotopic heart transplantation. DESIGN: Retrospective cohort study. SETTING: Single-center, university hospital. PARTICIPANTS: Adult patients undergoing orthotopic heart transplantation. INTERVENTIONS: A total of 609 adult heart transplant recipients were divided into 2 cohorts: patients who did not receive T3 (no T3 group, from 2009 to 2014), and patients who received T3 (T3 group, from 2015 to 2019). Propensity-adjusted logistic regression was performed to assess the association between T3 supplementation and PGD. MEASUREMENTS AND MAIN RESULTS: After applying exclusion criteria and propensity-score analysis, the final cohort included 461 patients. The incidence of PGD was not significantly different between the groups (33.9% no T3 group v 40.8% T3 group; p = 0.32). Mortality at 30 days (3% no T3 group v 2% T3 group; p = 0.53) and 1 year (10% no T3 group v 12% T3 group; p = 0.26) were also not significantly different. When assessing the severity of PGD, there were no differences in the groups' rates of moderate PGD (not requiring mechanical circulatory support other than an intra-aortic balloon pump) or severe PGD (requiring mechanical circulatory support other than an intra-aortic balloon pump). However, segmented time regression analysis revealed that patients in the T3 group were less likely to develop severe PGD. CONCLUSIONS: These findings indicated that recipient single-dose thyroid hormone administration may not protect against the development of PGD, but may attenuate the severity of PGD.