Transcripts associated with chronic lung allograft dysfunction in transbronchial biopsies of lung transplants.

Transplanted lungs suffer worse outcomes than other organ transplants with many developing chronic lung allograft dysfunction (CLAD), diagnosed by physiologic changes. Histology of transbronchial biopsies (TBB) yields little insight, and the molecular basis of CLAD is not defined. We hypothesized that gene expression in TBBs would reveal the nature of CLAD and distinguish CLAD from changes due simply to time posttransplant. Whole-genome mRNA profiling was performed with microarrays in 498 prospectively collected TBBs from the INTERLUNG study, 90 diagnosed as CLAD. Time was associated with increased expression of inflammation genes, for example, CD1E and immunoglobulins. After correcting for time, CLAD manifested not as inflammation but as parenchymal response-to-wounding, with increased expression of genes such as HIF1A, SERPINE2, and IGF1 that are increased in many injury and disease states and cancers, associated with development, angiogenesis, and epithelial response-to-wounding in pathway analysis. Fibrillar collagen genes were increased in CLAD, indicating matrix changes, and normal transcripts were decreased-dedifferentiation. Gene-based classifiers predicted CLAD with AUC 0.70 (no time-correction) and 0.87 (time-corrected). CLAD related gene sets and classifiers were strongly prognostic for graft failure and correlated with CLAD stage. Thus, in TBBs, molecular changes indicate that CLAD primarily reflects severe parenchymal injury-induced changes and dedifferentiation.

The allograft injury marker CXCL9 determines prognosis of anti-HLA antibodies after lung transplantation.

Despite the common detection of non-donor specific anti-HLA antibodies (non-DSAs) after lung transplantation, their clinical significance remains unclear. In this retrospective single-center cohort study of 325 lung transplant recipients, we evaluated the association between donor-specific HLA antibodies (DSAs) and non-DSAs with subsequent CLAD development. DSAs were detected in 30% of recipients and were associated with increased CLAD risk, with higher HRs for both de novo and high MFI (>5000) DSAs. Non-DSAs were detected in 56% of recipients, and 85% of DSA positive tests had concurrent non-DSAs. In general, non-DSAs did not increase CLAD risk in multivariable models accounting for DSAs. However, non-DSAs in conjunction with high BAL CXCL9 levels were associated with increased CLAD risk. Multivariable proportional hazards models demonstrate the importance of the HLA antibody-CXCL9 interaction: CLAD risk increases when HLA antibodies (both DSAs and non-DSAs) are detected in conjunction with high CXCL9. Conversely, CLAD risk is not increased when HLA antibodies are detected with low CXCL9. This study supports the potential utility of BAL CXCL9 measurement as a biomarker to risk stratify HLA antibodies for future CLAD. The ability to discriminate between high versus low-risk HLA antibodies may improve management by allowing for guided treatment decisions.

Impact of ex vivo lung perfusion on brain-dead donor lung utilization: The French experience.

Ex vivo lung perfusion (EVLP) is a valuable method for expanding the lung donor pool. Its indications currently differ across centers. This national retrospective cohort study aimed to describe the profile of donors with lungs transplanted after EVLP and determine the effectiveness of EVLP on lung utilization. We included brain-dead donors with at least one lung offered between 2012 and 2019 in France. Lungs transplanted without or after EVLP were compared with those that were rejected. Donor group phenotypes were determined with multiple correspondence analysis (MCA). The association between donor factors and lung transplantation was assessed with a multivariable multinomial logistic regression. MCA revealed that donors whose lungs were transplanted after EVLP had profiles similar to the donors whose lungs were declined and quite different from those of donors with lungs transplanted without EVLP. Donor predictors of graft nonuse included age ≥50 years, smoking history, PaO2 /FiO2 ratio ≤300 mmHg, abnormal chest imaging, and purulent secretions. EVLP increased utilization of lungs from donors with a smoking history, PaO2 /FiO2 ratio ≤300 mmHg, and abnormal chest imaging.

Immunity to varicella, measles, and mumps in patients evaluated for lung transplantation.

Vaccine-preventable viral infections are associated with increased risk of morbidity and mortality in post-transplant patients on immunosuppression regimens. Therefore, we studied rates of immunity against vaccine-preventable viruses in lung transplantation (LTx) candidates and their associations with underlying lung disease and clinical characteristics. We retrospectively studied 1025 consecutive adult patients who underwent first-time evaluation for LTx at a single center between January 2016 and October 2018. Viruses studied included varicella zoster (VZV), measles, and mumps. Young age (17-48 years old) was negatively associated with immunity for VZV (OR 4.54, p < .001), measles (OR 15.45, p < .001) and mumps (OR 3.1, p < .001), as compared to those 65+. Many LTx candidates with cystic fibrosis (CF) had undetectable virus-specific antibody titers including: 13.5% for VZV, 19.1% for measles, and 15.7% for mumps with significant odds of undetectable titers for VZV (OR 4.54, p < .001) and measles (OR 2.32, p = .010) as compared to those without CF. Therefore, a substantial number of patients undergoing LTx evaluation had undetectable virus-specific antibody titers. Our results emphasize the importance of screening for immunity to vaccine-preventable infections in this population and the need for revaccination in selected patients to boost their humoral immunity prior to transplantation.

A three-tier system for evaluation of organ procurement organizations' willingness to pursue and utilize nonideal donor lungs.

Lungs from "nonideal," but acceptable donors are underutilized; however, organ procurement organization (OPO) metrics do not reflect the extent to which OPO-specific practices contribute to these trends. We developed a comprehensive system to evaluate nonideal lung donor avoidance, or risk aversion among OPOs. Adult donors in the UNOS registry who donated ≥1 organ for transplantation between 2007 and 2018 were included. Nonideal donors had any of age>50, smoking history ≥20 pack-years, PaO2 /FiO2 ratio ≤350, donation after circulatory death, or increased risk status. OPO-level risk aversion in donor pursuit, consent attainment, lung recovery, and transplantation was assessed. Among 83916 donors, 70372 (83.9%) were nonideal. Unadjusted OPO-level rates of nonideal donor pursuit ranged from 81 to 100%. In a three-tier system of overall risk aversion, tier 3 OPOs (least risk-averse) had the highest rates of nonideal donor pursuit, consent attainment, lung recovery, and transplantation. Tier 1 OPOs (most risk-averse) had the lowest rates of donor pursuit, consent attainment, and lung recovery, but higher rates of transplantation compared to tier 2 OPOs (moderately risk-averse). Risk aversion varies among OPOs and across the donation process. OPO evaluations should reflect early donation process stages to best differentiate over- and underperforming OPOs and encourage optimal OPO-specific performance.

Simultaneous pancreas and kidney transplant after bilateral lung transplant for a recipient with cystic fibrosis.

Cystic fibrosis (CF) is an inherited autosomal recessive disorder. Despite optimized therapy, the majority of affected individuals ultimately die of respiratory failure. Lung transplantation is the only available therapy that deals definitively with the end-stage pulmonary disease and has become the treatment of choice for some of these patients. As patients with CF are living longer, extrapulmonary manifestations may develop including pancreatic failure, which manifests as exocrine insufficiency and CF-related diabetes (CFRD). Both of these can be managed through pancreas transplantation. We have previously reported our series of three simultaneous lung and pancreas transplants in patients with CF, which were complicated by surgical issues for both the thoracic and abdominal portions, rejection and resistant infections with disappointing long-term survival. Based on these results, a sequential approach was adopted: first, the thoracic transplant; and second, once the patient has recovered, the abdominal transplants. This is the first reported case of pancreas and kidney transplantation performed after a lung transplant in a patient with CF. It demonstrates a successful approach to treating CF with a lung transplant, and in an effort to improve the patient's long-term outcome, treating CFRD and pancreatic enzyme insufficiency, with a subsequent pancreas transplant.

Different-team procurements: A potential solution for the unintended consequences of change in lung allocation policy.

The new lung allocation policy has led to an increase in distant donors and consequently enhanced logistical burden of procuring organs. Though early single-center studies noted similar outcomes between same-team transplantation (ST, procuring team from transplanting center) and different-team transplantation (DT, procuring team from different center), the efficacy of DT in the contemporary era remains unclear. In this study, we evaluated the trend of DT, rate of transplanting both donor lungs, 1-year graft survival, and risk of Grade 3 primary graft dysfunction (PGD) using the Scientific Registry of Transplant Recipient (SRTR) database from 2006 to 2018. A total of 21619 patients (DT 2085, 9.7%) with 19837 donors were included. Utilization of DT decreased from 15.9% in 2006 to 8.5% in 2018. Proportions of two-lung donors were similar between the groups, and DT had similar 1-year graft survival as ST for both double (DT, HR 1.108, 95% CI 0.894-1.374) and single lung transplants (DT, HR 1.094, 95% CI 0.931-1.286). Risk of Grade 3 PGD was also similar between ST and DT. Given our results, expanding DT may be a feasible option for improving lung procurement efficiency in the current era, particularly in light of the COVID-19 pandemic.

A novel injury site-natural antibody targeted complement inhibitor protects against lung transplant injury.

Complement is known to play a role in ischemia and reperfusion injury (IRI). A general paradigm is that complement is activated by self-reactive natural IgM antibodies (nAbs), after they engage postischemic neoepitopes. However, a role for nAbs in lung transplantation (LTx) has not been explored. Using mouse models of LTx, we investigated the role of two postischemic neoepitopes, modified annexin IV (B4) and a subset of phospholipids (C2), in LTx. Antibody deficient Rag1-/- recipient mice were protected from LTx IRI. Reconstitution with either B4 or C2nAb restored IRI, with C2 significantly more effective than B4 nAb. Based on these information, we developed/characterized a novel complement inhibitor composed of single-chain antibody (scFv) derived from the C2 nAb linked to Crry (C2scFv-Crry), a murine inhibitor of C3 activation. Using an allogeneic LTx, in which recipients contain a full nAb repertoire, C2scFv-Crry targeted to the LTx, inhibited IRI, and delayed acute rejection. Finally, we demonstrate the expression of the C2 neoepitope in human donor lungs, highlighting the translational potential of this approach.

Critical care and ventilatory management of deceased organ donors impact lung use and recipient graft survival.

Current risk-adjusted models for donor lung use and lung graft survival do not include donor critical care data. We sought to identify modifiable donor physiologic and mechanical ventilation parameters that predict donor lung use and lung graft survival. This is a prospective observational study of donors after brain death (DBDs) managed by 19 Organ Procurement Organizations from 2016 to 2019. Demographics, mechanical ventilation parameters, and critical care data were recorded at standardized time points during donor management. The lungs were transplanted from 1811 (30%) of 6052 DBDs. Achieving ≥7 critical care endpoints was a positive predictor of donor lung use. After controlling for recipient factors, donor blood pH positively predicted lung graft survival (OR 1.48 per 0.1 unit increase in pH) and the administration of dopamine during donor management negatively predicted lung graft survival (OR 0.19). Tidal volumes ≤8 ml/kg predicted body weight (OR 0.65), and higher positive end-expiratory pressures (OR 0.91 per cm H2 O) predicted decreased donor lung use without affecting lung graft survival. A randomized clinical trial is needed to inform optimal ventilator management strategies in DBDs.

Management of lung transplantation in the COVID-19 era-An international survey.

It is unknown if solid organ transplant recipients are at higher risk for severe COVID-19. The management of a lung transplantation (LTx) program and the therapeutic strategies to adapt the immunosuppressive regimen and antiviral measures is a major issue in the COVID-19 era, but little is known about worldwide practice. We sent out to 180 LTx centers worldwide in June 2020 a survey with 63 questions, both regarding the management of a LTx program in the COVID-19 era and the therapeutic strategies to treat COVID-19 LTx recipients. We received a total of 78 responses from 15 countries. Among participants, 81% declared a reduction of the activity and 47% restricted LTx for urgent cases only. Sixteen centers observed deaths on waiting listed patients and eight centers performed LTx for COVID-19 disease. In 62% of the centers, COVID-19 was diagnosed in LTx recipients, most of them not severe cases. The most common immunosuppressive management included a decreased dose or pausing of the cell cycle inhibitors. Remdesivir, hydroxychloroquine, and azithromycin were the most proposed antiviral strategies. Most of the centers have been affected by the COVID-19 pandemic and proposed an active therapeutic strategy to treat LTx recipients with COVID-19.

Type-1 immunity and endogenous immune regulators predominate in the airway transcriptome during chronic lung allograft dysfunction.

Chronic lung allograft dysfunction (CLAD) remains the major complication limiting long-term survival among lung transplant recipients (LTRs). Limited understanding of CLAD immunopathogenesis and a paucity of biomarkers remain substantial barriers for earlier detection and therapeutic interventions for CLAD. We hypothesized the airway transcriptome would reflect key immunologic changes in disease. We compared airway brush-derived transcriptomic signatures in CLAD (n = 24) versus non-CLAD (n = 21) LTRs. A targeted assessment of the proteome using concomitant bronchoalveolar lavage (BAL) fluid for 24 cytokines/chemokines and alloimmune T cell responses was performed to validate the airway transcriptome. We observed an airway transcriptomic signature of differential genes expressed (DGEs) in CLAD marked by Type-1 immunity and striking upregulation of two endogenous immune regulators: indoleamine 2, 3 dioxygenase 1 (IDO-1) and tumor necrosis factor receptor superfamily 6B (TNFRSF6B). Advanced CLAD staging was associated with a more intense airway transcriptome signature. In a validation cohort using the identified signature, we found an area under the curve (AUC) of 0.77 for CLAD LTRs. Targeted proteomic analyses revealed a predominant Type-1 profile with detection of IFN-γ, TNF-α, and IL-1ß as dominant CLAD cytokines, correlating with the airway transcriptome. The airway transcriptome provides novel insights into CLAD immunopathogenesis and biomarkers that may impact diagnosis of CLAD.

COVID-19 in lung transplant recipients: A multicenter study.

This study describes the clinical presentation, treatment, and outcomes of SARS-CoV-2 infection in lung transplant recipients (LTRs). This is a multicenter, retrospective study of all adult LTRs with confirmed SARS-CoV-2 infection from March 4 until April 28, 2020 in six Spanish reference hospitals for lung transplantation. Clinical and radiological data, treatment characteristics, and outcomes were reviewed. Forty-four cases were identified in that period. The median time from transplantation was 4.2 (interquartile range: 1.11-7.3) years. Chest radiography showed acute parenchymal abnormalities in 32 (73%) cases. Hydroxychloroquine was prescribed in 41 (93%), lopinavir/ritonavir (LPV/r) in 14 (32%), and tocilizumab in 19 (43%) patients. There was a strong interaction between tacrolimus and LPV/r in all cases. Thirty-seven (84%) patients required some degree of respiratory support and/or oxygen therapy, and 13 (30%) were admitted to intermediate or intensive critical care units. Seventeen (39%) patients had died and 20 (45%) had been discharged at the time of the last follow-up. Deceased patients had a worse respiratory status and chest X-ray on admission and presented with higher D-dimer, interleukin-6, and lactate dehydrogenase levels. In this multicenter LTR cohort, SARS-CoV-2 presented with high mortality. Additionally, the severity of disease on presentation predicted subsequent mortality.

Frailty and aging-associated syndromes in lung transplant candidates and recipients.

Many lung transplant candidates and recipients are older and frailer compared to previous eras. Older patients are at increased risk for pre- and posttransplant mortality, but this risk is not explained by numerical age alone. This manuscript represents the product of the American Society of Transplantation (AST) conference on frailty. Experts in the field reviewed the latest published research on assessment of elderly and frail lung transplant candidates. Physical frailty, often defined as slowness, weakness, low physical activity, shrinking, and exhaustion, and frailty evaluation is an important tool for evaluation of age-associated dysfunction. Another approach is assessment by cumulative deficits, and both types of frailty are common in lung transplant candidates. Frailty is associated with death or delisting before transplant, and may be associated with posttransplant mortality. Sarcopenia, cognitive dysfunction, depression, and nutrition are other important components for patient evaluation. Aging-associated inflammation, telomere dysfunction, and adaptive immune system senescence may also contribute to frailty. Developing tools for frailty assessment and interventions holds promise for improving patient outcomes before and after lung transplantation.

Interleukin 6 trans-signaling is a critical driver of lung allograft fibrosis.

Histopathologic examination of lungs afflicted by chronic lung allograft dysfunction (CLAD) consistently shows both mononuclear cell (MNC) inflammation and mesenchymal cell (MC) fibroproliferation. We hypothesize that interleukin 6 (IL-6) trans-signaling may be a critical mediator of MNC-MC crosstalk and necessary for the pathogenesis of CLAD. Bronchoalveolar lavage (BAL) fluid obtained after the diagnosis of CLAD has approximately twofold higher IL-6 and soluble IL-6 receptor (sIL-6R) levels compared to matched pre-CLAD samples. Human BAL-derived MCs do not respond to treatment with IL-6 alone but have rapid and prolonged JAK2-mediated STAT3 Tyr705 phosphorylation when exposed to the combination of IL-6 and sIL-6R. STAT3 phosphorylation within MCs upregulates numerous genes causing increased invasion and fibrotic differentiation. MNC, a key source of both IL-6 and sIL-6R, produce minimal amounts of these proteins at baseline but significantly upregulate production when cocultured with MCs. Finally, the use of an IL-6 deficient recipient in a murine orthotopic transplant model of CLAD reduces allograft fibrosis by over 50%. Taken together these results support a mechanism where infiltrating MNCs are stimulated by resident MCs to release large quantities of IL-6 and sIL-6R which then feedback onto the MCs to increase invasion and fibrotic differentiation.

Comparison of donor scores in bilateral lung transplantation-A large single-center analysis.

Objectifying donor lung quality is difficult and currently there is no consensus. Several donor scoring systems have been proposed in recent years. They all lack large-scale external validation and widespread acceptance. A retrospective evaluation of 2201 donor lungs offered to the lung transplant program at the Medical University of Vienna between January 2010 and June 2018 was performed. Five different lung donor scores were calculated for each offer (Oto, ET, MALT, UMN-DLQI, and ODSS). Prediction of organ utilization, 1-year graft survival, and long-term outcome were analyzed for each score. 1049 organs were rejected at the initial offer (group I), 209 lungs declined after procurement (group II), and 841 lungs accepted and transplanted (group III). The Oto score was superior in predicting acceptance of the initial offer (AUC: 0.795; CI: 0.776-0.815) and actual donor utilization (AUC: 0.660; CI: 0.618-0.701). Prediction of 1-year graft survival was best using the MALT score, Oto score, and UMN-DLQI. Stratification of early outcome by MALT was significant for length of mechanical ventilation (LMV), PGD3 rates, ICU stay and hospital stay, and in-hospital-mortality, respectively. To the best of our knowledge, this study is the largest validation analysis comparing currently available donor scores. The Oto score was superior in predicting organ utilization, and MALT score and UMN-DLQI for predicting outcome after lung transplantation.

Early ß-lactam concentrations and infectious complications after lung transplantation.

Antibiotic underdosing in prophylactic antibiotic regimes after lung transplantation (LTx) can increase the risk of infection. We aimed to study whether ß-lactam concentrations achieved desirable pharmacodynamic targets in the early phase after LTx and the association between drug concentrations and the development of early infections or the acquisition of multidrug-resistant (MDR) strains. We reviewed patients in whom broad-spectrum ß-lactam levels were measured after LTx during antibiotic prophylaxis. ß-Lactam concentrations were considered "insufficient" if drug levels remained below four times the clinical breakpoint of the minimal inhibitory concentration for Pseudomonas aeruginosa. The primary outcome was the occurrence of an infection and/or acquisition of MDR pathogens in the first 14 days after transplantation. A total of 70 patients were included. "Insufficient" drug concentrations were found in 40% of patients. In 27% of patients, an early MDR pathogen was identified and 49% patients were diagnosed with an early posttransplant infection. Patients with "insufficient" drug concentrations acquired more frequently MDR bacteria and/or developed an infection than others (22/28, 79% vs. 20/42, 48% - p = .01). ß-Lactam levels were often found to be below the desired drug targets in the early phase after transplantation and may be associated with the occurrence of early infectious complications.

Histopathologic and radiologic assessment of nontransplanted donor lungs.

Donor organ shortage results in significant waiting list mortality. Donor lung assessment is currently based on donors' history, gas exchange, chest X-ray, bronchoscopy findings, and ultimately in situ inspection but remains subjective. We correlated histopathology and radiology in nontransplanted donor lungs with the clinical indications to decline the offered organ. Sixty-two donor lungs, not used for transplantation (2010-2019), were procured, air-inflated, frozen, scanned with computed tomography, systematically sampled, and histologically and radiologically assessed. Thirty-nine (63%) lungs were declined for allograft-related reasons. In 13/39 (33%) lungs, histology could not confirm the reason for decline, in an additional 8/39 (21%) lungs, histologic abnormalities were only considered mild. In 16/39 (41%) lungs, radiology could not confirm the reason for decline. Twenty-three (37%) donor lungs were not transplanted due to extrapulmonary causes, of which three (13%) lungs displayed severe histologic abnormalities (pneumonia, n = 2; emphysema, n = 1), in addition to mild emphysema in 9 (39%) lungs and minor bronchopneumonia in 1 (4%). Radiology revealed ground-glass opacities in 8/23 (35%) and emphysema in 4/23 (17%) lungs. Histopathologic and radiologic assessment of nontransplanted donor lungs revealed substantial discrepancy with the clinical reason for decline. Optimization of donor lung assessment is necessary to improve current organ acceptance rates.

Objective Estimates Improve Risk Stratification for Primary Graft Dysfunction after Lung Transplantation.

Primary graft dysfunction (PGD) is a major cause of early mortality after lung transplant. We aimed to define objective estimates of PGD risk based on readily available clinical variables, using a prospective study of 11 centers in the Lung Transplant Outcomes Group (LTOG). Derivation included 1255 subjects from 2002 to 2010; with separate validation in 382 subjects accrued from 2011 to 2012. We used logistic regression to identify predictors of grade 3 PGD at 48/72 h, and decision curve methods to assess impact on clinical decisions. 211/1255 subjects in the derivation and 56/382 subjects in the validation developed PGD. We developed three prediction models, where low-risk recipients had a normal BMI (18.5-25 kg/m(2) ), chronic obstructive pulmonary disease/cystic fibrosis, and absent or mild pulmonary hypertension (mPAP<40 mmHg). All others were considered higher-risk. Low-risk recipients had a predicted PGD risk of 4-7%, and high-risk a predicted PGD risk of 15-18%. Adding a donor-smoking lung to a higher-risk recipient significantly increased PGD risk, although risk did not change in low-risk recipients. Validation demonstrated that probability estimates were generally accurate and that models worked best at baseline PGD incidences between 5% and 25%. We conclude that valid estimates of PGD risk can be produced using readily available clinical variables.

Hepatitis From Spiroplasma sp. in an Immunocompromised Patient.

A 70-year-old lung transplant recipient patient was admitted with fever, nausea, abdominal pain, peripheral edema and pronounced weakness. An initial work-up for presumed infection revealed cholestatic hepatitis, leukocytosis and thrombocytopenia, but failed to detect a pathogen. An increased glucose uptake exclusively in the liver was demonstrated by positron emission tomography. Liver biopsy showed basophilic inclusions in the cytoplasm of hepatocytes. Broad- range 16S rRNA gene PCR followed by sequence analysis yielded Spiroplasma sp. in two independent blood samples and the liver biopsy, confirming Spiroplasma sp. as the causative agent. Antibiotic treatment with doxycycline and azithromycin led to complete recovery.

National Healthcare Delivery Systems Influence Lung Transplant Outcomes for Cystic Fibrosis.

Successful lung transplantation (LTx) depends on multiple components of healthcare delivery and performance. Therefore, we conducted an international registry analysis to compare post-LTx outcomes for cystic fibrosis (CF) patients using the UNOS registry in the United States and the National Health Service (NHS) Transplant Registry in the United Kingdom. Patients with CF who underwent lung or heart-lung transplantation in the United States or United Kingdom between January 1, 2000 and December 31, 2011 were included. The primary outcome was all-cause mortality. Kaplan-Meier analysis and Cox proportional hazards regression evaluated the effect of healthcare system and insurance on mortality after LTx. 2,307 US LTx recipients and 451 individuals in the United Kingdom were included. 894 (38.8%) US LTx recipients had publically funded Medicare/Medicaid insurance. US private insurance and UK patients had improved median predicted survival compared with US Medicare/Medicaid recipients (p < 0.001). In multivariable Cox regression, US Medicare/Medicaid insurance was associated with worse survival after LTx (US private: HR0.78,0.68-0.90,p = 0.001 and UK: HR0.63,0.41-0.97, p = 0.03). This study in CF patients is the largest comparison of LTx in two unique health systems. Both the United States and United Kingdom have similar early survival outcomes, suggesting important dissemination of best practices internationally. However, the performance of US public insurance is significantly worse and may put patients at risk.