Chronic lung allograft dysfunction small airways reveal a lymphocytic inflammation gene signature

Chronic lung allograft dysfunction (CLAD) is the major barrier to long-term survival following lung transplantation, and new mechanistic biomarkers are needed. Lymphocytic bronchitis (LB) precedes CLAD and has a defined molecular signature. We hypothesized that this LB molecular signature would be associated with CLAD in small airway brushings independent of infection. We quantified RNA expression from small airway brushings and transbronchial biopsies, using RNAseq and digital RNA counting, respectively, for 22 CLAD cases and 27 matched controls. LB metagene scores were compared across CLAD strata by Wilcoxon rank sum test. We performed unbiased host transcriptome pathway and microbial metagenome analysis in airway brushes and compared machine-learning classifiers between the two tissue types. This LB metagene score was increased in CLAD airway brushes (p = .002) and improved prediction of graft failure (p = .02). Gene expression classifiers based on airway brushes outperformed those using transbronchial biopsies. While infection was associated with decreased microbial alpha-diversity (p ≤ .04), neither infection nor alpha-diversity was associated with LB gene expression. In summary, CLAD was associated with small airway gene expression changes not apparent in transbronchial biopsies in this cohort. Molecular analysis of airway brushings for diagnosing CLAD merits further examination in multicenter cohorts.

Lung donation after medical assistance in dying at home

Organ donation after medical assistance in dying (MAID) has only been possible for patients having the MAID procedure performed at a hospital facility due to prohibitive warm ischemic times. Herein, we describe a protocol for lung donation following MAID at home and demonstrate excellent postoperative outcomes. Lung donation following MAID at home is possible and should be considered by transplant programs.

Sleep-disordered breathing after lung transplantation: An observational cohort study

Data concerning sleep-disordered breathing (SDB) after lung transplantation (LTX) are scarce. This study aims to analyze prevalence, associated factors, and impact on survival of moderate to severe SDB in a large cohort of consecutive LTX patients (n = 219). Patients underwent a diagnostic polysomnography 1 year after LTX. Moderate to severe SDB was present in 57.5% of patients, with the highest prevalence in chronic obstructive pulmonary disease/emphysema (71.1%) and pulmonary fibrosis (65.1%). SDB patients were older, mostly male, and had higher body mass index and neck circumference. Nocturnal diastolic and 24-hour blood pressures were higher in SDB patients. In 45 patients, polysomnography was also performed pre-LTX. Compared to pre-LTX, mean apnea/hypopnea index (AHI) increased significantly after LTX. A significant correlation was seen between lung function parameters and AHI, suggesting a role of decreased caudal traction on the pharynx. Presence of SDB had no impact on mortality or prevalence of chronic lung allograft dysfunction. However, survival was better in continuous positive airway pressure (CPAP) compliant SDB patients compared to SDB patients without CPAP treatment. These findings may be pertinent for systematic screening of SDB after LTX.

Simultaneous pectus excavatum correction and lung transplantation-A case series

Severe chest wall deformities are considered an absolute contraindication for lung transplantation. The significantly impaired chest compliance associated with pectus excavatum is thought to result in a high risk of postoperative respiratory complications and significant morbidity and mortality. We herein report our pooled institutional experience consisting of 3 patients who underwent bilateral lung transplantation and simultaneous correction of a pectus excavatum. Two of the patients were children and 1 patient had severe asymmetric pectus. All patients received a size-reduced double lung transplant and the deformity was corrected by a Nuss or modified Ravitch procedure. The perioperative course was complicated by prolonged weaning requiring tracheostomy in 2 of the 3 patients. However, long-term results were good and all 3 patients are alive in excellent clinical condition 72, 60, and 12 months after the transplantation. This case series demonstrates that patients with severe chest wall deformities should not a priori be excluded from lung transplantation, and a combined approach is feasible for selected patients.

Impact of the elimination of the donation service area on United States lung transplant practices and outcomes at high and low competition centers

In November 2017, the donation service area (DSA) was removed as the primary unit of US donor lung allocation. Our primary objective was to evaluate the effect of this change on recipient characteristics, the use of pretransplant extracorporeal membrane oxygenation (ECMO), and on index hospitalization length of stay (LOS) and early posttransplant complications. We also assessed whether these outcomes differed in high and low competition centers, as defined by the Herfindahl-Hirschman Index. Following DSA removal, there was a 9-day decrease in median waitlist time (P = .001) and an increase in median lung allocation score (40 vs 42, P < .0001) but no difference in the need for pretransplant ECMO (incidence rate ratio = 1.16, P = .12). Median LOS increased from 17 to 19 days in the post-DSA era (P = .01). There was no difference in posttransplant outcomes, including prolonged ventilation, new dialysis, or early survival, in the general cohort or between competition groups. High competition centers saw an 18.5-minute increase in ischemic time compared to low competition centers (P = .04) but did not differentially increase single lung transplants or pretransplant ECMO utilization. Overall, DSA elimination was associated with increased posttransplant LOS but no significant differences in pretransplant ECMO or other posttransplant outcomes. Effects were largely similar at low and high competition centers.

Evaluation of 10 years of parainfluenza virus, human metapneumovirus, and respiratory syncytial virus infections in lung transplant recipients

Respiratory tract infection with pneumoviruses (PVs) and paramyxoviruses (PMVs) are increasingly associated with chronic lung allograft dysfunction (CLAD) in lung transplant recipients (LTRs). Ribavirin may be a treatment option but its effectiveness is unclear, especially with respect to infection severity. We retrospectively analyzed 10 years of PV/PMV infections in LTRs. The main end points were forced expiratory volume in 1 second (FEV₁ ) at 3 and 6 months postinfection, expressed as a percentage of pre-infection FEV₁ and incidence of new or progressed CLAD 6 months postinfection. A total of 139 infections were included: 88 severe infections (63%) (defined as >10% FEV₁ loss at infection) and 51 mild infections (37%) (≤10% FEV₁ loss). Overall postinfection CLAD incidence was 20%. Associations were estimated on postinfection FEV₁ for ribavirin vs no ribavirin (+13.2% [95% CI: 7.79; 18.67]) and severe vs mild infection (-11.1% [95% CI: -14.76; -7.37]). Factors associated with CLAD incidence at 6 months were ribavirin treatment (odds ratio (OR [95% CI]) 0.24 [0.10; 0.59]), severe infection (OR [95% CI] 4.63 [1.66; 12.88]), and mycophenolate mofetil use (OR [95% CI] 0.38 [0.14; 0.97]). These data provide valuable information about the outcomes of lung transplant recipients with these infections and suggests possible associations of ribavirin use and infection severity with long-term outcomes. Well-designed prospective trials are needed to confirm these findings.

Successful bridge to lung transplantation with transcatheter aortic valve replacement

End-stage lung disease and advanced cardiac conditions are frequently seen together and represent a clinical dilemma. Even though both issues may be amenable to surgical management, combining lung transplant with surgical valve repair is rarely done and theoretically associated with increased morbidity and mortality risks, especially in elderly patients. Here, we describe 2 patients presenting with end-stage lung disease and significant aortic stenosis who were successfully bridged to lung transplant via transcatheter aortic valve replacement. Patient 1 was a 66-year-old man who underwent a double lung transplant 56 days after transcatheter aortic valve replacement. Patient 2 was a 70-year-old man who underwent a single right lung transplant 103 days after transcatheter aortic valve replacement. Both patients had uneventful postoperative courses and are alive at the 1-year time point with excellent performance status. This report suggests that transcatheter aortic valve replacement may favorably impact lung transplant candidacy for patients with end-stage lung disease in the setting of severe aortic stenosis, likely representing a better alternative to concomitant aortic valve replacement and lung transplant in elderly patients.

Use of a Bluetooth tablet-based technology to improve outcomes in lung transplantation: A pilot study

The impact of remote patient monitoring platforms to support the postoperative care of solid organ transplant recipients is evolving. In an observational pilot study, 28 lung transplant recipients were enrolled in a novel postdischarge home monitoring program and compared to 28 matched controls during a 2-year period. Primary endpoints included hospital readmissions and total days readmitted. Secondary endpoints were survival and inflation-adjusted hospital readmission charges. In univariate analyses, monitoring was associated with reduced readmissions (incidence rate ratio [IRR]: 0.56; 95% confidence interval [CI]: 0.41-0.76; P < .001), days readmitted (IRR: 0.46; 95% CI: 0.42-0.51; P < .001), and hospital charges (IRR: 0.52; 95% CI: 0.51-0.54; P < .001). Multivariate analyses also showed that remote monitoring was associated with lower incidence of readmission (IRR: 0.38; 95% CI: 0.23-0.63; P < .001), days readmitted (IRR: 0.14; 95% CI: 0.05-0.37; P < .001), and readmission charges (IRR: 0.11; 95% CI: 0.03-0.46; P = .002). There were 2 deaths among monitored patients compared to 6 for controls; however, this difference was not significant. This pilot study in lung transplant recipients suggests that supplementing postdischarge care with remote monitoring may be useful in preventing readmissions, reducing subsequent inpatient days, and controlling hospital charges. A multicenter, randomized control trial should be conducted to validate these findings.

COVID-19 in lung transplant patients: A case series

Several case reports and small case series have been published on coronavirus disease 2019 infection after solid organ transplantation; however, thus far there are limited data on coronavirus disease 2019 infections in lung transplant patients. In the present single-center case series we discuss 10 lung transplant patients with a documented severe acute respiratory syndrome coronavirus 2 infection, diagnosed with nasopharyngeal swab in 8 and bronchoalveolar lavage in 2. Eight of 10 patients needed hospital admission, of whom 1 was in the intensive care unit. He died after 2 weeks from multiple organ failure. The remaining nine patients recovered. Cell cycle inhibitors were withheld in all patients, whereas the calcineurin inhibitor and corticosteroids were continued at the same dose, with an acceptable outcome.

COVID-19 in lung transplant recipients: A single center case series from New York City

There are limited data describing COVID-19 in lung transplant recipients. We performed a single center, retrospective case series study of lung transplant patients followed by the Columbia Lung Transplant program who tested positive for SARS-CoV-2 between March 19 and May 19, 2020. Thirty-two lung transplant patients developed mild (16%), moderate (44%), or severe (41%) COVID-19. The median age of patients was 65 years, and the median time from lung transplant was 5.6 years. Symptoms included cough (66%), dyspnea (50%), fever (47%), and gastrointestinal upset (44%). Patients received hydroxychloroquine (84%), azithromycin (75%), augmented steroids (44%), tocilizumab (19%), and remdesivir (9%). Eleven patients (34%) died at a median time of 14 days from admission. Complications during admission included: acute kidney injury (63%), transaminitis (31%), shock (31%), acute respiratory distress syndrome (25%), neurological events (25%), arrhythmias (22%), and venous thromboembolism (9%). Compared to patients with moderate COVID-19, patients with severe COVID-19 had higher peak white blood cell counts (15.8 vs 7 × 10³ /uL, P = .019), C-reactive protein (198 vs. 107 mg/L, P = .010) and D-dimer (8.6 vs. 2.1 ug/mL, P = .004) levels, and lower nadir lymphocyte counts (0.09 vs. 0.4 × 10³ /uL, P = .006). COVID-19 is associated with severe illness and a high mortality rate in lung transplant recipients.

SARS-CoV-2 infection in two patients following recent lung transplantation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has become a global health problem with pandemic character. Lung transplant recipients may be particularly at risk due to the high degree of immunosuppression and the lung being the organ primarily affected by COVID-19. We describe a 16-year-old male and a 64-year-old female recently lung transplanted patients with COVID-19 during inpatient rehabilitation. Both patients were receiving triple immunosuppressive therapy and had no signs of allograft dysfunction. Both patients had close contact with a person who developed COVID-19 and were tested positive for SARS-CoV-2. Subsequently, both patients underwent systematic screening and SARS-CoV-2 was ultimately detected. Although the 16-year-old boy was completely asymptomatic, the 64-year-old woman developed only mild COVID-19. Immunosuppressive therapy was unchanged and no experimental treatment was initiated. No signs of graft involvement or dysfunction were noticed. In conclusion, our report of patients with asymptomatic SARS-CoV-2 infection and mild COVID-19, respectively, may indicate that lung transplant recipients are not per se at risk for severe COVID-19. Further observations and controlled trials are urgently needed to study SARS-CoV-2 infection in lung transplant recipients.

COVID-19 pneumonia in lung transplant recipients: Report of 2 cases

Coronavirus disease 2019 (COVID-19) has been declared pandemic since March 2020. In Europe, Italy was the first nation affected by this infection. We report anamnestic data, clinical features, and therapeutic management of 2 lung transplant recipients with confirmed COVID-19 pneumonia. Both patients were in good clinical condition before the infection and were receiving immunosuppression with calcineurin inhibitors (CNI), mycophenolate mofetil, and corticosteroids. Whereas mycophenolate mofetil was withdrawn in both cases, CNI were suspended only in the second patient. The first patient always maintained excellent oxygen saturation throughout hospitalization with no need for additional oxygen therapy. He was discharged with a satisfactory pulmonary function and a complete resolution of radiological and clinical findings. However, at discharge SARS-CoV-2 RNA could still be detected in the nasopharyngeal swab and in the stools. The second patient required mechanical ventilation, had a progressive deterioration of his clinical conditions, and had a fatal outcome. Further insight into SARS-CoV-2 infection is eagerly awaited to improve the outcome of transplant recipients affected by COVID-19 pneumonia.

When tissue is the issue: A histological review of chronic lung allograft dysfunction

Although chronic lung allograft dysfunction (CLAD) remains the major life-limiting factor following lung transplantation, much of its pathophysiology remains unknown. The discovery that CLAD can manifest both clinically and morphologically in vastly different ways led to the definition of distinct subtypes of CLAD. In this review, recent advances in our understanding of the pathophysiological mechanisms of the different phenotypes of CLAD will be discussed with a particular focus on tissue-based and molecular studies. An overview of the current knowledge on the mechanisms of the airway-centered bronchiolitis obliterans syndrome, as well as the airway and alveolar injuries in the restrictive allograft syndrome and also the vascular compartment in chronic antibody-mediated rejection is provided. Specific attention is also given to morphological and molecular markers for early CLAD diagnosis or histological changes associated with subsequent CLAD development. Evidence for a possible overlap between different forms of CLAD is presented and discussed. In the end, "tissue remains the (main) issue," as we are still limited in our knowledge about the actual triggers and specific mechanisms of all late forms of posttransplant graft failure, a shortcoming that needs to be addressed in order to further improve the outcome of lung transplant recipients.

Lung transplant waitlist outcomes in the United States and patient travel distance

There is a broad range of patient travel distances to reach a lung transplant hospital in the United States. Whether patient travel distance is associated with waitlist outcomes is unknown. We present a cohort study of patients listed between January 1, 2006 and May 31, 2017 using the Scientific Registry of Transplant Recipients. Travel distance was measured from the patient's permanent zip code to the transplant hospital using shared access signature URL access to Google Maps, and assessed using multivariable competing risk regression models. There were 22 958 patients who met inclusion criteria. Median travel distance was 69.7 miles. Among patients who traveled > 60 miles, 41.2% bypassed a closer hospital and sought listing at a more distant hospital. In the adjusted models, when compared to patients who traveled ≤60 miles, patients who traveled >360 miles had a 27% lower subhazard ratio (SHR) for waitlist removal (SHR 0.73, 95% confidence interval [CI]: 0.60, 0.89, P = .002), 16% lower subhazard for waitlist death (SHR 0.84; 95% CI 0.73-0.95, P = .07), and 13% increased likelihood for transplant (SHR 1.13, 95% CI: 1.07, 1.20, P < .001). Many patients bypassed the nearest transplant hospital, and longer patient travel distance was associated with favorable waitlist outcomes.

Living-donor single-lobe lung transplantation for pulmonary hypertension due to alveolar capillary dysplasia with misalignment of pulmonary veins

This is a case report of a successful single-lobe lung transplantation for pulmonary hypertension secondary to alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV). A 6-year-old boy underwent living-donor single-lobe transplantation with the right lower lobe from his 31-year-old mother. The pretransplantation graft size matching was acceptable: the estimated graft forced vital capacity (FVC) was 96.5% of the recipient's predicted FVC, and the graft size measured by computed tomography (CT) volumetry was 166% of the recipient's chest cavity volume. Right pneumonectomy followed by implantation was performed under cardiopulmonary bypass (CPB). The pulmonary arterial pressure was significantly decreased to 31/12 mm Hg immediately after transplantation, and the first PaO₂ /FiO₂ in the intensive-care unit (ICU) was 422 mm Hg. Lung perfusion scintigraphy showed 97.5% perfusion to the right implanted lung 3 months after transplantation. Chest CT showed a mass rapidly growing in the native left upper lobe 6 months after transplantation, which was diagnosed as posttransplant lymphoproliferative disorder (PTLD) by a CT-guided biopsy. After immunosuppressant reduction and six courses of chemotherapy with rituximab, he underwent native left upper lobectomy for salvage lung resection 13 months after transplantation. Seven months after lobectomy, he has returned to normal school life without any sign of tumor recurrence.

Spontaneous diaphragmatic rupture as a complication following lung transplantation

Spontaneous diaphragm rupture is a rare but potentially life-threatening condition, requiring urgent surgical intervention. Here we present two patients who developed spontaneous right hemidiaphragm rupture with abdominal visceral herniation into the thoracic cavity several days following bilateral lung transplantation, as an unusual complication. Both patients' surgeries were performed through bilateral anterior thoracotomies and were uneventful. There may be an association with this complication and patients suffering with emphysema, typically receiving donor lungs smaller than their native lungs, and with significant pretransplant exposure to steroids, factors that when combined may contribute to an increased risk of spontaneous diaphragmatic rupture in the absence of a significant precipitant. If a similar clinical picture is seen, teams managing lung transplant recipients should be aware of this potential complication and recognize the need for urgent intervention.

Highlights from the clinical trials in organ transplantation (CTOT)-20 and CTOT-22 Consortium studies in lung transplant

Long-term survival after lung transplant lags behind that of other commonly transplanted organs, reflecting the current incomplete understanding of the mechanisms involved in the development of posttransplant lung injury, rejection, infection, and chronic allograft dysfunction. To address this unmet need, 2 ongoing National Institute of Allergy and Infectious Disease funded studies through the Clinical Trials in Organ Transplant Consortium (CTOT) CTOT-20 and CTOT-22 were dedicated to understanding the clinical factors and biological mechanisms that drive chronic lung allograft dysfunction and those that maintain cytomegalovirus polyfunctional protective immunity. The CTOT-20 and CTOT-22 studies enrolled 800 lung transplant recipients at 5 North American centers over 3 years. Given the number and complexity of subjects included, CTOT-20 and CTOT-22 utilized innovative data transfers and capitalized on patient-entered data collection to minimize site manual data entry. The data were coupled with an extensive biosample collection strategy that included DNA, RNA, plasma, serum, bronchoalveolar lavage fluid, and bronchoalveolar lavage cell pellet. This Special Article describes the CTOT-20 and CTOT-22 protocols, data and biosample strategy, initial results, and lessons learned through study execution.

Initial lung transplantation experience with uncontrolled donation after cardiac death in North America

Uncontrolled donation after cardiac death (uDCD) has the potential to ameliorate the shortage of suitable lungs for transplant. To date, no lung transplant data from these donors are available from North America. We describe the successful use of these donors using a simple method of in situ lung inflation so that the organ can be protected from warm ischemic injury. Forty-four potential donors were approached, and family consent was obtained in 30 cases (68%). Of these, the lung transplant team evaluated 16 uDCDs on site, and 14 were considered for transplant pending ex vivo lung perfusion assessment. Five lungs were ultimately used for transplant (16.7% use rate from consented donors). The mean warm ischemic time was 2.8 hours. No primary graft dysfunction grade 3 was observed at 24, 48, or 72 hours after transplant. Median intensive care unit stay was 5 days (range: 2-78 days), and median hospital stay was 17 days (range: 8-100 days). The 30-day mortality was 0%. Four of 5 patients are alive at a median of 651 days (range: 121-1254 days) with preserved lung function. This study demonstrates the proof of concept and the potential for uDCD lung donation using a simple donor intervention.

IL-22 is required for the induction of bronchus-associated lymphoid tissue in tolerant lung allografts

Long-term survival after lung transplantation remains profoundly limited by graft rejection. Recent work has shown that bronchus-associated lymphoid tissue (BALT), characterized by the development of peripheral nodal addressin (PNAd)-expressing high endothelial venules and enriched in B and Foxp3+ T cells, is important for the maintenance of allograft tolerance. Mechanisms underlying BALT induction in tolerant pulmonary allografts, however, remain poorly understood. Here, we show that the development of PNAd-expressing high endothelial venules within intragraft lymphoid follicles and the recruitment of B cells, but not Foxp3+ cells depends on IL-22. We identify graft-infiltrating gamma-delta (γδ) T cells and Type 3 innate lymphoid cells (ILC3s) as important producers of IL-22. Reconstitution of IL-22 at late time points through retransplantation into wildtype hosts mediates B cell recruitment into lymphoid follicles within the allograft, resulting in a significant increase in their size, but does not induce PNAd expression. Our work has identified cellular and molecular requirements for the induction of BALT in pulmonary allografts during tolerance induction and may provide a platform for the development of new therapies for lung transplant patients.

Idiopathic pulmonary fibrosis lung transplant recipients are at increased risk for EBV-associated posttransplant lymphoproliferative disorder and worse survival

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (EBV-PTLD) is a serious complication in lung transplant recipients (LTRs) associated with significant mortality. We performed a single-center retrospective study to evaluate the risks for PTLD in LTRs over a 7-year period. Of 611 evaluable LTRs, we identified 28 cases of PTLD, with an incidence of 4.6%. Kaplan-Meier analysis showed a decreased freedom from PTLD in idiopathic pulmonary fibrosis (IPF)-LTRs (P < .02). Using a multivariable Cox proportional hazards model, we found IPF (hazard ratio [HR] 3.51, 95% confidence interval [CI] 1.33-8.21, P = .01) and alemtuzumab induction therapy (HR 2.73, 95% CI 1.10-6.74, P = .03) as risk factors for PTLD, compared to EBV mismatch (HR: 34.43, 95% CI 15.57-76.09, P < .0001). Early PTLD (first year) was associated with alemtuzumab use (P = .04), whereas IPF was a predictor for late PTLD (after first year) (P = .002), after controlling for age and sex. Kaplan-Meier analysis revealed a shorter time to death from PTLD in IPF LTRs compared to other patients (P = .04). The use of alemtuzumab in EBV mismatch was found to particularly increase PTLD risk. Together, our findings identify IPF LTRs as a susceptible population for PTLD. Further studies are required to understand the mechanisms driving PTLD in IPF LTRs and develop strategies to mitigate risk.

Pseudomonas aeruginosa and acute rejection independently increase the risk of donor-specific antibodies after lung transplantation

Factors contributing to donor-specific HLA antibody (DSA) development after lung transplantation have not been systematically evaluated. We hypothesized that the isolation of Pseudomonas aeruginosa in respiratory specimens would increase the risk of DSA development. Our objective was to determine the risk of DSA development associated with the isolation of Pseudomonas aeruginosa after lung transplantation. We conducted a single-center retrospective cohort study of primary lung transplant recipients and examined risk factors for DSA development using Cox regression models. Of 460 recipients, 205 (45%) developed DSA; the majority developed Class II DSA (n = 175, 85%), and 145 of 205 (71%) developed DSA to HLA-DQ alleles. Univariate time-dependent analyses revealed that isolation of Pseudomonas from respiratory specimens, acute cellular rejection, and lymphocytic bronchiolitis are associated with an increased risk of DSA development. In multivariable analyses, Pseudomonas isolation, acute cellular rejection, and lymphocytic bronchiolitis remained independent risk factors for DSA development. Additionally, there was a direct association between the number of positive Pseudomonas cultures and the risk of DSA development. Our findings suggest that pro-inflammatory events including acute cellular rejection, lymphocytic bronchiolitis, and Pseudomonas isolation after transplantation are associated with an increased risk of DSA development.

Treatment with 3-aminobenzamide during ex vivo lung perfusion of damaged rat lungs reduces graft injury and dysfunction after transplantation

Ex vivo lung perfusion (EVLP) with pharmacological reconditioning may increase donor lung utilization for transplantation (LTx). 3-Aminobenzamide (3-AB), an inhibitor of poly(ADP-ribose) polymerase (PARP), reduces ex vivo lung injury in rat lungs damaged by warm ischemia (WI). Here we determined the effects of 3-AB reconditioning on graft outcome after LTx. Three groups of donor lungs were studied: Control (Ctrl): 1 hour WI + 3 hours cold ischemia (CI) + LTx; EVLP: 1 hour WI + 3 hours EVLP + LTx; EVLP + 3-AB: 1 hour WI + 3 hours EVLP + 3-AB (1 mg^. mL^-1 ) + LTx. Two hours after LTx, we determined lung graft compliance, edema, histology, neutrophil counts in bronchoalveolar lavage (BAL), mRNA levels of adhesion molecules within the graft, as well as concentrations of interleukin-6 and 10 (IL-6, IL-10) in BAL and plasma. 3-AB reconditioning during EVLP improved compliance and reduced lung edema, neutrophil infiltration, and the expression of adhesion molecules within the transplanted lungs. 3-AB also attenuated the IL-6/IL-10 ratio in BAL and plasma, supporting an improved balance between pro- and anti-inflammatory mediators. Thus, 3-AB reconditioning during EVLP of rat lung grafts damaged by WI markedly reduces inflammation, edema, and physiological deterioration after LTx, supporting the use of PARP inhibitors for the rehabilitation of damaged lungs during EVLP.

Deciphering the role of eosinophils in solid organ transplantation

Eosinophils are rare granulocytes that belong to the innate arm of the immune system. This cell population is traditionally defined as a destructive and cytotoxic mediator in asthma and helminth infection. Limited data in transplantation have suggested that eosinophils play a similar role in potentiating deleterious organ inflammation and immunologic rejection. Contrary to this long-held notion, recent data have uncovered the possibility that eosinophils play an alternative role in immune homeostasis, defense against a wide range of pathogens, as well as downregulation of deleterious inflammation. Specifically, translational data from small animal models of lung transplantation have demonstrated a critical role for eosinophils in the downregulation of alloimmunity. These findings shed new light on the unique immunologic features of the lung allograft and demonstrate that environmental polarization may alter the phenotype and function of leukocyte populations previously thought to be static in nature. In this review, we provide an update on eosinophils in the homeostasis of the lung as well as other solid organs.

Molecular phenotyping of rejection-related changes in mucosal biopsies from lung transplants

Diagnosing lung transplant rejection currently depends on histologic assessment of transbronchial biopsies (TBB) with limited reproducibility and considerable risk of complications. Mucosal biopsies are safer but not histologically interpretable. Microarray-based diagnostic systems for TBBs and other transplants suggest such systems could assess mucosal biopsies as well. We studied 243 mucosal biopsies from the third bronchial bifurcation (3BMBs) collected from seven centers and classified them using unsupervised machine learning algorithms. Using the expression of a set of rejection-associated transcripts annotated in kidneys and validated in hearts and lung transplant TBBs, the algorithms identified and scored major rejection and injury-related phenotypes in 3BMBs without need for labeled training data. No rejection or injury, rejection, late inflammation, and recent injury phenotypes were thus scored in new 3BMBs. The rejection phenotype correlated with IFNG-inducible transcripts, the hallmarks of rejection. Progressive atrophy-related changes reflected by the late inflammation phenotype in 3BMBs suggest widespread time-dependent airway deterioration, which was especially pronounced after two years posttransplant. Thus molecular assessment of 3BMBs can detect rejection in a previously unusable biopsy format with potential utility in patients with severe lung dysfunction where TBB is not possible and provide unique insights into airway deterioration. ClinicalTrials.gov NCT02812290.

Amphiregulin contributes to airway remodeling in chronic allograft dysfunction after lung transplantation

Chronic lung allograft dysfunction (CLAD), a condition of excess matrix deposition and airways fibrosis, limits survival after lung transplantation. Amphiregulin (Areg) is an epidermal growth factor receptor (EGFR) ligand suggested to regulate airway injury and repair. We sought to determine whether Areg expression increases in CLAD, localize the cellular source of Areg induction in CLAD, and assess its effects on airway matrix deposition. Lung fluid Areg protein was quantified in patients with or without CLAD. In situ hybridization was performed to localize Areg and EGFR transcript in CLAD and normal lung tissue. Expression of hyaluronan, a matrix constituent that accumulates in CLAD, was measured in Areg-exposed bronchial epithelial cells in the presence or absence of an EGFR inhibitor. We demonstrated that lung fluid Areg protein was significantly increased in CLAD in a discovery and replication cohort. Areg and EGFR transcripts were abundantly expressed within CLAD tissue, localized to basally distributed airway epithelial cells overlying fibrotic regions. Areg-exposed bronchial epithelial cells increased hyaluronan and hyaluronan synthase expression in an EGFR-dependent manner. Collectively, these novel observations suggest that Areg contributes to airway remodeling and CLAD. Moreover these data implicate a role for EGFR signaling in CLAD pathogenesis, suggesting novel therapeutic targets.

The unique moral permissibility of uncontrolled lung donation after circulatory death

Implementing uncontrolled donation after circulatory determination of death (uDCDD) in the United States could markedly improve supply of donor lungs for patients in need of transplants. Evidence from US pilot programs suggests families support uDCDD, but only if they are asked permission for using invasive organ preservation procedures prior to initiation. However, non-invasive strategies that confine oxygenation to lungs may be applicable to the overwhelming majority of potential uDCDD donors that have airway devices in place as part of standard resuscitation. We propose an ethical framework for lung uDCDD by: (a) initiating post mortem preservation without requiring prior permission to protect the opportunity for donation until an authorized party can be found; (b) using non-invasive strategies that confine oxygenation to lungs; and (c) maintaining strict separation between the healthcare team and the organ preservation team. Attempting uDCDD in this way has great potential to obtain more transplantable lungs while respecting donor autonomy and family wishes, securing public support, and enabling authorized persons to affirm or cease preservation decisions without requiring evidence of prior organ donation intent. It ensures prioritization of life-saving, the opportunity to allow willing donors to donate, and respect for bodily integrity while adhering to current ethical norms.

Estimated impact of hepatitis C-positive lung donor utilization on US donor lung supply

The availability of highly effective direct-acting antiviral agents (DAAs) for hepatitis C virus (HCV) infection has led to reports of safely transplanting HCV⁺ donor lungs into HCV^- candidates. However, it remains unclear how the ability to use HCV⁺ donor lungs for lung transplant could affect the number of donor lungs available for transplant. Using Scientific Registry of Transplant Recipient data, we identified all deceased organ donors within the United States from March 1, 2015, to February 28, 2018, and stratified by HCV status. A donor prediction model for lung donation was derived and validated within HCV^- donors and applied to HCV⁺ donors to estimate the number of acceptable HCV⁺ lung donors. Of 29 481 eligible donors, 2054 (7.0%) were HCV⁺ donors with 82 HCV⁺ donors' lungs being used for transplant during the study period. The prediction model for donor lung donation (specificity 92.6%, sensitivity 65.6%) estimated 248 HCV⁺ donors (75 nonviremic, 173 viremic) were acceptable for lung transplant during the study period, suggesting that 166 acceptable HCV⁺ lung donors were discarded. The ability to transplant lungs from HCV⁺ organ donors would lead to an estimated nationwide increase of at least 55 donor lungs per year, including 44 from HCV viremic donors.

Combined lung and liver procurement in controlled donation after circulatory death using normothermic abdominal perfusion. Initial experience in two Spanish centers

Combining simultaneously lung and liver procurement in controlled donation after circulatory death (cDCD) using normothermic abdominal perfusion (NRP) for abdominal grafts and cooling and rapid recovery technique (RR) for the lungs increases the complexity of the procurement procedure and might injure the grafts. A total of 19 cDCDs from two centers using this combined procedure were evaluated, and 16 liver and 21 lung transplantations were performed. As controls, 34 donors after brain death (DBDs) were included (29 liver and 41 lung transplantations were performed). Two cDCD liver recipients developed primary nonfunction (12.5%). No cases of ischemic cholangiopathy were observed among cDCD recipients. The 1-year and 2-year liver recipients survival was 87.5% and 87.5% for the cDCD group, and 96% and 84.5% for the DBD group, respectively (P = .496). The 1-year and 2-year lung recipients survival was 84% and 84% for the cDCD group and 90% and 90% for the DBD group, respectively (P = .577). This is the largest experience ever reported in cDCD with the use of NRP combined with RR of the lungs. This combined method offers an outstanding recovery rate and liver and lung recipients survival comparable with those transplanted with DBDs. Further studies are needed to confirm our findings.

The impact of first untreated subclinical minimal acute rejection on risk for chronic lung allograft dysfunction or death after lung transplantation

Acute cellular rejection (ACR) is a significant risk factor for chronic lung allograft dysfunction (CLAD). Although clinically manifest and higher grade (≥A2) ACR is generally treated with augmented immunosuppression, management of minimal (grade A1) ACR remains controversial. In our program, patients with subclinical and spirometrically stable A1 rejection (StA1R) are routinely not treated with augmented immunosuppression. We hypothesized that an untreated first StA1R does not increase the risk of CLAD or death compared to episodes of spirometrically stable no ACR (StNAR). The cohort was drawn from all consecutive adult, first, bilateral lung transplantations performed between 1999 and 2017. Biopsies obtained in the first-year posttransplant were paired with (forced expiratory volume in 1 second FEV₁ ). The first occurrence of StA1R was compared to a time-matched StNAR. The risk of CLAD or death was assessed using univariable and multivariable Cox proportional hazards models. The analyses demonstrated no significant difference in risk of CLAD or death in patients with a first StA1R compared to StNAR. This largest study to date shows that, in clinically stable patients, an untreated first A1 ACR in the first-year posttransplant is not significantly associated with an increased risk for CLAD or death. Watchful-waiting approach may be an acceptable tactic for stable A1 episodes in lung transplant recipients.

Lung transplant outcomes are influenced by severity of neutropenia and granulocyte colony-stimulating factor treatment

Although neutropenia is a common complication after lung transplant, its relationship with recipient outcomes remains understudied. We evaluated a retrospective cohort of 228 adult lung transplant recipients between 2008 and 2013 to assess the association of neutropenia and granulocyte colony-stimulating factor (GCSF) treatment with outcomes. Neutropenia was categorized as mild (absolute neutrophil count 1000-1499), moderate (500-999), or severe (<500) and as a time-varying continuous variable. Associations with survival, acute rejection, and chronic lung allograft dysfunction (CLAD) were assessed with the use of Cox proportional hazards regression. GCSF therapy impact on survival, CLAD, and acute rejection development was analyzed by propensity score matching. Of 228 patients, 101 (42.1%) developed neutropenia. Recipients with severe neutropenia had higher mortality rates than those of recipients with no (adjusted hazard ratio [aHR] 2.97, 95% confidence interval [CI] 1.05-8.41, P = .040), mild (aHR 14.508, 95% CI 1.58-13.34, P = .018), or moderate (aHR 3.27, 95% CI 0.89-12.01, P = .074) neutropenia. Surprisingly, GCSF treatment was associated with a higher risk for CLAD in mildly neutropenic patients (aHR 3.49, 95% CI 0.93-13.04, P = .063), although it did decrease death risk in severely neutropenic patients (aHR 0.24, 95% CI 0.07-0.88, P = .031). Taken together, our data point to an important relationship between neutropenia severity and GCSF treatment in lung transplant outcomes.

A B cell-dependent pathway drives chronic lung allograft rejection after ischemia-reperfusion injury in mice

Chronic lung allograft dysfunction (CLAD) limits long-term survival after lung transplant (LT). Ischemia-reperfusion injury (IRI) promotes chronic rejection (CR) and CLAD, but the underlying mechanisms are not well understood. To examine mechanisms linking IRI to CR, a mouse orthotopic LT model using a minor alloantigen strain mismatch (C57BL/10 [B10, H-2^b ] → C57BL/6 [B6, H-2^b ]) and isograft controls (B6→B6) was used with antecedent minimal or prolonged graft storage. The latter resulted in IRI with subsequent airway and parenchymal fibrosis in prolonged storage allografts but not isografts. This pattern of CR after IRI was associated with the formation of B cell-rich tertiary lymphoid organs within the grafts and circulating autoantibodies. These processes were attenuated by B cell depletion, despite preservation of allograft T cell content. Our observations suggest that IRI may promote B cell recruitment that drives CR after LT. These observations have implications for the mechanisms leading to CLAD after LT.

Absence of evidence that respiratory viral infections influence pediatric lung transplantation outcomes: Results of the CTOTC-03 study

Based on reports in adult lung transplant recipients, we hypothesized that community-acquired respiratory viral infections (CARVs) would be a risk factor for poor outcome after pediatric lung transplant. We followed 61 pediatric lung transplant recipients for 2+ years or until they met a composite primary endpoint including bronchiolitis obliterans syndrome/obliterative bronchiolitis, retransplant, or death. Blood, bronchoalveolar lavage, and nasopharyngeal specimens were obtained with standard of care visits. Nasopharyngeal specimens were obtained from recipients with respiratory viral symptoms. Respiratory specimens were interrogated for respiratory viruses by using multiplex polymerase chain reaction. Donor-specific HLA antibodies, self-antigens, and ELISPOT reactivity were also evaluated. Survival was 84% (1 year) and 68% (3 years). Bronchiolitis obliterans syndrome incidence was 20% (1 year) and 38% (3 years). The primary endpoint was met in 46% of patients. CARV was detected in 156 patient visits (74% enterovirus/rhinovirus). We did not find a relationship between CARV recovery from respiratory specimens and the primary endpoint (hazard ratio 0.64 [95% confidence interval: 0.25-1.59], P = .335) or between CARV and the development of alloimmune or autoimmune humoral or cellular responses. These findings raise the possibility that the immunologic impact of CARV following pediatric lung transplant is different than that observed in adults.

Total parenteral nutrition in ex vivo lung perfusion: Addressing metabolism improves both inflammation and oxygenation

Ex vivo lung perfusion (EVLP) protocols generally limit metabolic supplementation to insulin and glucose. We sought to determine whether the addition of total parenteral nutrition (TPN) would improve lung function in EVLP. Ten porcine lungs were perfused using EVLP for 24 hours and supplemented with insulin and glucose. In the treatment group (n = 5), the perfusate was also supplemented with a continuous infusion of TPN containing lipids, amino acids, essential vitamins, and cofactors. Physiologic parameters and perfusate electrolytes were continuously evaluated. Perfusate lactate, lipid and branch chain amino acid (BCAA) concentrations were also analyzed to elucidate how substrates were being utilized over time. Lungs in the TPN group exhibited significantly better oxygenation. Perfusate sodium was more stable in the TPN group. In the control group, free fatty acids (FFA) were quickly depleted, reaching negligible levels early in the perfusion. Alternatively, BCAA in the control group rose continually over the perfusion demonstrating a shift toward proteolysis for energy substrate. In the TPN group, both FFA and BCAA concentrations remained stable at in vivo levels after initial stabilization. TNF-α concentrations were lower in the TPN group. The addition of TPN in EVLP allows for better electrolyte composition, decreased inflammation, and improved graft performance.

A nonlinear relationship between visceral adipose tissue and frailty in adult lung transplant candidates

Frailty is a state of decreased physiologic reserve associated with poor outcomes before and after lung transplantation. Obesity, particularly central obesity characterized by excess proinflammatory visceral adipose tissue (VAT), is associated with incident frailty in middle-aged and older adults. The association between VAT and frailty in advanced lung disease, however, is unknown. In two, nonoverlapping multicenter cohorts of adults listed for lung transplantation, we measured VAT area on bioelectrical impedance assay (BIA) in one cohort and cross-sectional VAT and subcutaneous adipose tissue (SAT) areas on abdominal computed tomography (CT) in the other. We identified a nonlinear relationship between greater VAT by BIA and frailty. In fully adjusted piecewise regression models, every 20 cm² increase in VAT area was associated with 50% increased odds of frailty in subjects with high VAT (95% CI 1.2-1.9, P < .001), and 10% decreased odds of frailty (95% CI 0.7-1.04, P = .12) in subjects with low VAT. Compared to frail subjects with low VAT, those with high VAT were more likely to have low grip strength and less likely to have weight loss, suggesting that mechanisms of frailty may differ by VAT. Further investigation of mechanisms linking VAT and frailty may identify new targets for prevention and treatment.

Blood CD9+ B cell, a biomarker of bronchiolitis obliterans syndrome after lung transplantation

Bronchiolitis obliterans syndrome is the main limitation for long-term survival after lung transplantation. Some specific B cell populations are associated with long-term graft acceptance. We aimed to monitor the B cell profile during early development of bronchiolitis obliterans syndrome after lung transplantation. The B cell longitudinal profile was analyzed in peripheral blood mononuclear cells from patients with bronchiolitis obliterans syndrome and patients who remained stable over 3 years of follow-up. CD24^hi CD38^hi transitional B cells were increased in stable patients only, and reached a peak 24 months after transplantation, whereas they remained unchanged in patients who developed a bronchiolitis obliterans syndrome. These CD24^hi CD38^hi transitional B cells specifically secrete IL-10 and express CD9. Thus, patients with a total CD9⁺ B cell frequency below 6.6% displayed significantly higher incidence of bronchiolitis obliterans syndrome (AUC = 0.836, PPV = 0.75, NPV = 1). These data are the first to associate IL-10-secreting CD24^hi CD38^hi transitional B cells expressing CD9 with better allograft outcome in lung transplant recipients. CD9-expressing B cells appear as a contributor to a favorable environment essential for the maintenance of long-term stable graft function and as a new predictive biomarker of bronchiolitis obliterans syndrome-free survival.

Donor prone positioning protects lungs from injury during warm ischemia

A large proportion of controlled donation after circulatory death (cDCD) donor lungs are declined because cardiac arrest does not occur within a suitable time after the withdrawal of life-sustaining therapy. Improved strategies to preserve lungs after asystole may allow the recovery team to arrive after death actually occurs and enable the recovery of lungs from more cDCD donors. The aim of this study was to determine the effect of donor positioning on the quality of lung preservation after cardiac arrest in a cDCD model. Cardiac arrest was induced by withdrawal of ventilation under anesthesia in pigs. After asystole, animals were divided into 2 groups based on body positioning (supine or prone). All animals were subjected to 3 hours of warm ischemia. After the observation period, donor lungs were explanted and preserved at 4°C for 6 hours, followed by 6 hours of physiologic and biological lung assessment under normothermic ex vivo lung perfusion. Donor lungs from the prone group displayed significantly greater quality as reflected by better function during ex vivo lung perfusion, less edema formation, less cell death, and decreased inflammation compared with the supine group. A simple maneuver of donor prone positioning after cardiac arrest significantly improves lung graft preservation and function.

Vendor-specific microbiome controls both acute and chronic murine lung allograft rejection by altering CD4+ Foxp3+ regulatory T cell levels

Despite standardized postoperative care, some lung transplant patients suffer multiple episodes of acute and chronic rejection while others avoid graft problems for reasons that are poorly understood. Using an established model of C57BL/10 to C57BL/6 minor antigen mismatched single lung transplantation, we now demonstrate that the recipient microbiota contributes to variability in the alloimmune response. Specifically, mice from the Envigo facility in Frederick, Maryland contain nearly double the number of CD4⁺ Foxp3⁺ regulatory T cells (T_regs ) than mice from the Jackson facility in Bar Harbor, Maine or the Envigo facility in Indianapolis, Indiana (18 vs 9 vs 7%). Lung graft recipients from the Maryland facility thus do not develop acute or chronic rejection. Treatment with broad-spectrum antibiotics decreases T_regs and increases both acute and chronic graft rejection in otherwise tolerant strains of mice. Constitutive depletion of regulatory T cells, using Foxp3-driven expression of diphtheria toxin receptor, leads to the development of chronic rejection and supports the role of T_regs in both acute and chronic alloimmunity. Taken together, our data demonstrate that the microbiota of certain individuals may contribute to tolerance through T_reg -dependent mechanisms and challenges the practice of indiscriminate broad-spectrum antibiotic use in the perioperative period.

Early clinical experience of bacteriophage therapy in 3 lung transplant recipients

Bacteriophage therapy (BT) uses bacteriophages to treat pathogenic bacteria and is an emerging strategy against multidrug-resistant (MDR) infections. Experience in solid organ transplant is limited. We describe BT in 3 lung transplant recipients (LTR) with life-threatening MDR infections caused by Pseudomonas aeruginosa (n = 2) and Burkholderia dolosa (n = 1). For each patient, lytic bacteriophages were selected against their bacterial isolates. BT was administered for variable durations under emergency Investigational New Drug applications and with patient informed consent. Safety was assessed using clinical/laboratory parameters and observed clinical improvements described, as appropriate. All patients received concurrent antibiotics. Two ventilator-dependent LTR with large airway complications and refractory MDR P. aeruginosa pneumonia received BT. Both responded clinically and were discharged from the hospital off ventilator support. A third patient had recurrent B. dolosa infection following transplant. Following BT initiation, consolidative opacities improved and ventilator weaning was begun. However, infection relapsed on BT and the patient died. No BT-related adverse events were identified in the 3 cases. BT was well tolerated and associated with clinical improvement in LTRs with MDR bacterial infection not responsive to antibiotics alone. BT may be a viable adjunct to antibiotics for patients with MDR infections.

Pirfenidone exerts beneficial effects in patients with IPF undergoing single lung transplantation

Pirfenidone demonstrated pleiotropic antiinflammatory effects in various experimental and clinical settings. The aim of this study was to assess the impact of previous treatment with pirfenidone on short-term outcomes after single lung transplantation (SLTx). Therefore, patients with idiopathic pulmonary fibrosis (IPF) who were undergoing SLTx were screened retrospectively for previous use of pirfenidone and compared to respective controls. Baseline parameters and short-term outcomes were recorded and analyzed. In total, 17 patients with pirfenidone were compared with 26 patients without antifibrotic treatment. Baseline characteristics and severity of disease did not differ between groups. Use of pirfenidone did not increase blood loss, wound-healing, or anastomotic complications. Severity of primary graft dysfunction at 72 hours was less (0.3 ± 0.6 vs 1.4 ± 1.3, P = .002), and length of mechanical ventilation (37.5 ± 34.8 vs 118.5 ± 151.0 hours, P = .016) and intensive care unit (ICU) stay (6.6 ± 7.1 vs 15.6 ± 20.3, P = .089) were shorter in patients with pirfenidone treatment. An independent beneficial effect of pirfenidone was confirmed by regression analysis while controlling for confounding variables (P = .016). Finally, incidence of acute cellular rejections within the first 30 days after SLTx was lower in patients with previous pirfenidone treatment (0.0% vs 19.2%; P = .040). Our data suggest a beneficial role of previous use of pirfenidone in patients with IPF who were undergoing SLTx.

Unintended consequences of changes to lung allocation policy

Organ allocation for transplantation aims to balance the principles of justice and medical utility to optimally utilize a scarce resource. To address practical considerations, the United States is divided into 58 donor service areas (DSA), each constituting the first unit of allocation. In November 2017, in response to a lawsuit in New York, an emergency action change to lung allocation policy replaced the DSA level of allocation for donor lungs with a 250 nautical mile circle around the donor hospital. Similar policy changes are being implemented for other organs including heart and liver. Findings from a recent US Department of Health and Human Services report, supplemented with data from our institution, suggest that the emergency policy has not resulted in a change in the type of patients undergoing lung transplantation (LT) or early postoperative outcomes. However, there has been a significant decline in local LT, where donor and recipient are in the same DSA. With procurement teams having to travel greater distances, organ ischemic time has increased and median organ cost has more than doubled. We propose potential solutions for consideration at this critical juncture in the field of transplantation. Policymakers should choose equitable and sustainable access for this lifesaving discipline.

Postreperfusion plasma endothelial activation markers are associated with acute kidney injury after lung transplantation

Acute kidney injury (AKI) is common after lung transplantation, but molecular markers remain poorly studied. The endothelial activation markers soluble thrombomodulin (sTM), protein C, and plasminogen activator inhibitor-1 (PAI-1) are implicated in kidney microcirculatory injury in animal models of AKI. We tested the association of 6-hour postreperfusion plasma levels of these markers with posttransplant AKI severity in patients enrolled in the Lung Transplant Outcomes Group prospective cohort study at the University of Pennsylvania during two eras: 2004-06 (n = 61) and 2013-15 (n = 67). We defined AKI stage through postoperative day 5 using Kidney Disease Improving Global Outcomes creatinine criteria. We used multivariable ordinal logistic regression to determine the association of each biomarker with AKI, adjusted for primary graft dysfunction and extracorporeal life support. AKI occurred in 57 (45%) patients across both eras: 28 (22%) stage 1, 29 (23%) stage 2-3. Higher sTM and lower protein C plasma levels were associated with AKI stage in each era and remained so in multivariable models utilizing both eras (sTM: OR 1.76 [95% CI 1.19-2.60] per standard deviation, P = .005; protein C: OR 0.54 [1.19-2.60], P = .003). We conclude that 6-hour postreperfusion plasma sTM and protein C levels are associated with early postlung transplant AKI severity.

A randomized trial of everolimus-based quadruple therapy vs standard triple therapy early after lung transplantation

Calcineurin inhibitor (CNI) therapy after lung transplantation increases risk of kidney failure. Early everolimus-based quadruple low CNI immunosuppression may improve renal function without compromising efficacy or safety. A prospective, randomized, open-label, 12-month multicenter trial was conducted at 8 German sites. Patients 3-18 months after lung transplantation were randomized (1:1), stratified by baseline estimated glomerular filtration rate (eGFR). In the quadruple low CNI regimen, patients received everolimus (target trough level 3-5 ng/mL) with reduced CNI (tacrolimus 3-5 ng/mL or cyclosporine 25-75 ng/mL) and a cell cycle inhibitor plus prednisone. In the standard triple CNI regimen, patients received tacrolimus (target trough level >5 ng/mL) or cyclosporine (>100 ng/mL) and a cell cycle inhibitor plus prednisone. Of the 180 patients screened, 130 were randomized: 67 in the quadruple low CNI group and 63 in the standard triple CNI group. The primary endpoint (eGFR after 12 months) demonstrated superiority of the quadruple low CNI regimen: 64.5 mL/min vs 54.6 mL/min for the standard triple group (least squares mean, analysis of covariance; P < .001). Key efficacy parameters (biopsy-proven acute rejection, chronic lung allograft dysfunction, and death) and safety endpoints were similar between both groups. Quadruple low CNI immunosuppression early after lung transplantation was demonstrated to be efficacious and safe. Clinical trials registry: ClinicalTrials.gov NCT01404325.

Parenteral administration of oral medications in lung transplant recipients: An underrecognized problem

Microcrystalline cellulose (MCC) is an insoluble material commonly used as a binder and filler in oral medications. Identification of pulmonary intravascular deposition of MCC in transbronchial biopsies from lung transplant (LT) recipients following parenteral injection of oral medications has only been reported once. A search of our surgical pathology electronic database was performed from January 1, 2000 to November 1, 2017 using the text "transplant transbronchial." The diagnosis field for all cases retrieved was then searched for the text "cellulose." These cases were queried for patient demographics and outcomes. Between January 1, 2000 and November 1, 2017, 1558 lung transplants were performed in 1476 individual patients at our institution; 12 were identified to have MCC in their lung tissue. Patients with MCC identified on biopsies were more likely to be transplanted for cystic fibrosis versus other indications and younger versus older. MCC identified in 2 of our cases was favored to be donor derived. Of the 12 patients, 6 (50%) are deceased. MCC within the pulmonary vasculature may be an indicator of increased complications, mortality, or shortened survival in LT recipients. Detecting intravascular MCC and distinguishing it from aspirated foreign material can be challenging. Awareness of the differential diagnosis for pulmonary foreign material is of paramount importance for the pathologist.