Defining a natural killer cell-enriched molecular rejection-like state in lung transplant transbronchial biopsies.

In lung transplantation, antibody-mediated rejection (AMR) diagnosed using the International Society for Heart and Lung Transplantation criteria is uncommon compared with other organs, and previous studies failed to find molecular AMR (ABMR) in lung biopsies. However, understanding of ABMR has changed with the recognition that ABMR in kidney transplants is often donor-specific antibody (DSA)-negative and associated with natural killer (NK) cell transcripts. We therefore searched for a similar molecular ABMR-like state in transbronchial biopsies using gene expression microarray results from the INTERLUNG study (#NCT02812290). After optimizing rejection-selective transcript sets in a training set (N = 488), the resulting algorithms separated an NK cell-enriched molecular rejection-like state (NKRL) from T cell-mediated rejection (TCMR)/Mixed in a test set (N = 488). Applying this approach to all 896 transbronchial biopsies distinguished 3 groups: no rejection, TCMR/Mixed, and NKRL. Like TCMR/Mixed, NKRL had increased expression of all-rejection transcripts, but NKRL had increased expression of NK cell transcripts, whereas TCMR/Mixed had increased effector T cell and activated macrophage transcripts. NKRL was usually DSA-negative and not recognized as AMR clinically. TCMR/Mixed was associated with chronic lung allograft dysfunction, reduced one-second forced expiratory volume at the time of biopsy, and short-term graft failure, but NKRL was not. Thus, some lung transplants manifest a molecular state similar to DSA-negative ABMR in kidney and heart transplants, but its clinical significance must be established.

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.

Characteristics and outcomes among vaccinated lung transplant patients with breakthrough COVID-19.

BACKGROUND: Despite multiple studies evaluating the immunological responsiveness to vaccines, the clinical effectiveness of the two-dose mRNA vaccine schedule among lung transplant (LT) patients has not been evaluated. METHODS: We included LT patients who tested positive for SARS-CoV-2 on a nasopharyngeal swab between March 1, 2020, and August 25, 2021 (n = 70). The study group was divided based on their vaccination status. RESULTS: During the study period, 14 fully vaccinated LT patients with one of the mRNA vaccines tested positive for COVID-19 (median age 54, range 30-62 years, M:F 9:5). The vaccinated cohort was younger with bilateral LT, have suppurative conditions as the transplant indication, and present with milder symptoms. However, pulmonary parenchymal involvement was seen among all 12 patients where computed tomography (CT) of chest was available. The laboratory profile indicated a more subdued inflammatory response among the vaccinated group. A lower proportion of vaccinated patients developed respiratory failure, needed ICU admission or ventilator support, although none of the differences achieved statistical significance. None of the vaccinated patients succumbed to COVID-19 during the study period, while the 4-week mortality among unvaccinated patients was nearly 15% (8/56). CONCLUSIONS: In this cohort of vaccinated LT patients who developed breakthrough COVID-19, the clinical course, risk of complications, and outcomes trended better than unvaccinated patients. However, universal involvement of the allograft demonstrates the continued vulnerability of these patients to significant sequelae from COVID-19. Future studies may evaluate the incremental protection of vaccination after the completion of the third dose of mRNA vaccines among LT patients.

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.

Gait-speed and oxygen flow during six-minute walk test predicts mortality in patients with advanced lung disease.

The six-minute walk test (6MWT) is a useful tool to predict outcomes in patients with advanced lung diseases. Greater distance walked has been shown to have more favorable prognostic value compared to other recorded variables.  We reviewed the medical records of 164 patients with advanced lung disease who underwent lung transplant evaluation. Results of the 6MWT (distance walked, oxygen required, and mean gait speed) were recorded and analyzed with respect to mortality. 6MWT mean oxygen (O2) flow via nasal cannula was 3.5 ± 3.7 L/min. The distance walked in meters (m) and % predicted were inversely associated with mortality, OR: 0.995 (0.992-0.998) and 0.970 (0.950-0.990), respectively. Patients who walked < 200 meters (OR: 2.1 (1.1-4.0)) or < 45% of predicted, OR: 2.7 (1.2-5.7) had higher mortality. O2 flow during the test had a direct association with mortality (OR: 1.1 (1.0-1.2). In multivariate analysis, O2 flow > 3.5 L/min remained predictive of mortality, OR: 1.1 (1.0-1.2). Mean gait speed was higher in patient who lived compared with patients who died (mean 0.83 ± 0.35 m/mim vs mean 0.69 ± 0.33 m/min, respectively, p= 0.03). Gait speed was a predictor of survival, OR 3.4 (1.1, 10.6). O2 flow during the 6MWT was an independent predictor of mortality in patients with advanced lung disease. The patients that required more than 3.5 L/m of O2 had a higher mortality. Faster gait speed during the 6MWT was also associated with better survival.

Belatacept for renal rescue in lung transplant patients.

Renal failure causes morbidity and mortality after lung transplantation and is aggravated by exposure to nephrotoxic immunosuppressant (IS) drugs. We report an off-label experience using belatacept for lung transplant recipients with severe renal insufficiency to reduce nephrotoxic IS exposure. We analyzed data retrospectively from a consecutive series of lung transplant patients with renal insufficiency in whom belatacept treatment was initiated between June 2012 and June 2014 at the University of Maryland Medical Center. Eight patients received belatacept because of acute or chronic renal insufficiency (median) GFR 24 (IQR 18-26). Glomerular filtration rate (GFR) remained stable in two patients and increased in five. One patient with established renal and respiratory failure received only the induction dose of belatacept and died 4 months later of respiratory and multisystem organ failure. Calcineurin inhibitor or sirolimus exposure was safely withheld or reduced without moderate or severe acute rejection during ongoing belatacept in the other seven patients. FEV1 remained stable over the 6-month study interval. Belatacept use appears to permit safe transient reduction in conventional immunosuppressive therapy and was associated with stable or improved renal function in a small retrospective series of lung transplant recipients with acute or chronic renal insufficiency.

Outpatient management of Post-COVID syndrome - single center experience.

BACKGROUND: COVID patients continue to experience unremitting symptoms that extend far beyond the initial illness. While there is rapid accumulation of data on acute COVID treatment in hospitalized patients, little is known regarding post-COVID management. OBJECTIVES: To describe our center's experience treating post-COVID sub-syndromes encountered in Post-COVID Lung Clinic. METHODS: We retrospectively reviewed data on 98 post-COVID patients evaluated in our clinic between 07/01/2020-12/31/2022. We encountered three distinct post-COVID subtypes: 1) respiratory complaints associated with increased O2 requirements and abnormal CT findings (post-COVID interstitial lung disease [ILD]), 2) respiratory complaints associated with tachycardia (post-COVID dyspnea-tachycardia syndrome [DTS]). Post-COVID ILD patients (n = 28) received steroids in combination with cell cycle inhibitor (mycophenolate mofetil-MMF). Post-COVID DTS patients (n = 16) were treated with metoprolol. 3) A third, undifferentiated group presented with mild respiratory complaints and normal spirometry (n = 17) and was followed in clinic without initiation of a specific treatment. RESULTS: In treated post-COVID ILD patients, mean oxygen requirements at rest (1.96 ± 1.79 L/NC) decreased to 0.89 ± 1.29 L/NC at 6 months follow-up, p = 0.005. In patients with post-COVID DTS, mean heart rate at rest decreased (98 ± 15 bpm to 79 ± 11 bpm) at 6 months follow-up, p = 0.023. 60 % of patients reported an improvement in exertional dyspnea. CONCLUSIONS: Our descriptive study presents a single center outpatient COVID-19 clinic experience. We encountered 3 post-COVID sub-syndromes and describe their treatments: post-COVID interstitial lung disease [ILD] treated with a novel regimen of MMF and steroids, post COVID dyspnea-tachycardia syndrome [DTS] treated with metoprolol, and a third subgroup with mild undifferentiated symptoms without specific treatment.

Crossroads between Autoimmunity and COVID-19 in Lung Transplant Recipients.

The presence of a certain group of auto-antibodies (AAbs) is known to correlate with the severity of COVID-19. It is, however, unknown if such AAbs are prevalent and impact COVID-19-related outcomes in lung transplant recipients (LTRs) who are immunosuppressed. We performed a retrospective study of LTRs with COVID-19 and analyzed samples before and after COVID-19 for IgG AAbs. AAbs analysis was carried out using autoimmune and coronavirus microarray and the resulting cross-sectional differences in Ab-scores and clinical variables were analyzed using Fischer's Exact test for categorical variables and a paired t-test for continuous variables. Linear regression was used to analyze the differences in Ab-scores and COVID-19 severity. LTRs with non-severe [NS gp (n = 10)], and severe [S gp (n = 8)] COVID-19 disease were included. Ferritin and acute respiratory failure were higher in the S group (p = 0.03; p < 0.0001). Among the AAbs analyzed, interferon-related AAbs (IFN-alpha2, IFN-beta, IFN lamba, IFN-epsilon), eight interleukin-related AAbs, and several tissue-related AAbs were also found to be changed significantly from pre- to post-COVID-19 (p < 0.05). IFN-lambda (p = 0.03) and IL-22 (p = 0.002) were significantly associated with COVID-19 severity and remained significant in linear regression analysis while controlling for other variables. AAbs are common in LTRs, and certain groups of antibodies are particularly enhanced in LTRs with severe COVID-19. Preliminary observations of this study need to be confirmed by a larger sample size.

Pulmonary hypertension before first and second lung transplantation.

BACKGROUND: Pulmonary hypertension (PH) is frequently encountered in patients with advanced lung disease before the first and second lung transplantation. We sought to determine whether there is any relationship between pulmonary hemodynamics obtained before first and second lung transplantation. We also assessed whether PH has prognostic implications in lung transplant patients going for second transplantation. METHODS: We included consecutive adult (16-yr-old or older) patients who underwent lung re-transplantation, between 1997 and 2009, and had right heart catheterization before their first and second lung transplantation. RESULTS: Eighteen patients were included in the study. Age at first transplantation was 50.4 (SD 10.4) yr, and bronchiolitis obliterans syndrome (BOS) in the transplanted lung was the only indication for re-transplantation. PH was observed in 39% of the patients before the first lung transplant and in 56% of the subjects before re-transplantation (p = 0.91). Pre-capillary PH was present in 28% (n = 5) and 33% (n = 6) of the patients before first and second lung transplantation, respectively. None of the hemodynamic variables obtained before the first transplant predicted the development of PH before re-transplantation. PH before re-transplantation did not predict survival or development of BOS after re-transplantation. CONCLUSIONS: PH before initial lung transplantation did not predict the development of PH before the second transplantation. In our cohort, PH before second lung transplantation did not predict outcomes after re-transplantation.

Spirometry testing for extracorporeal membrane oxygenation (ECMO) bridge to transplant patients.

PURPOSE: ECMO can provide a bridge to transplantation and improve survival for patients with advanced lung disease. Although pulmonary function testing (PFT) is an important component of the lung allocation score (LAS), it is not always feasible on patients requiring ECMO. While generally safe, PFT testing has contraindications and is not recommended in unstable patients. Currently there are no recommendations regarding the performance of spirometry in ECMO patients. STUDY DESIGN: and Methods: We reviewed data on five patients with advanced lung disease requiring ECMO-bridge to transplant. After careful consideration of the theoretical physiologic risks associated with forced expiratory maneuvers, bedside spirometry was performed in order to update the patients' LAS. RESULTS: All patients successfully completed three forced expiratory maneuvers in the seated position with a bedside spirometer. Vital signs and ECMO flow were stable during testing and without complication. In 2 patients who had both a LAS pre and post spirometry, the LAS increased by 3-5 points. CONCLUSION: Spirometry results are pivotal to organ allocation under current organ sharing protocols. This case series demonstrates that bedside spirometry testing may be performed safely in patients on ECMO awaiting lung transplantation without appreciable side effects, leading to a more accurate LAS score.

Biological Variation of Donor-Derived Cell-Free DNA in Stable Lung Transplant Recipients.

BACKGROUND: Prior studies demonstrate that donor-derived cell-free DNA (dd-cfDNA) in lung transplant recipients may serve as a marker of allograft injury for detecting allograft rejection and infection. Clinical interpretation of dd-cfDNA requires understanding its biological variation in stable lung transplant patients in order to identify abnormal results suggesting underlying allograft dysfunction. This study establishes the biological variation and reference change values (RCV) of dd-cfDNA in stable lung transplant recipients using an analytically validated assay with an established analytic coefficient of variation (CVA). METHODS: The AlloSure® assay, a targeted, sequencing-based approach, was used to measure plasma dd-cfDNA in a cohort of lung transplant patients at 4 centers that used dd-cfDNA to monitor for allograft dysfunction in preference to surveillance transbronchial biopsy. Patients with stable allograft function and ≥3 dd-cfDNA samples were included. Intraindividual coefficient of variation (CVI), interindividual CV (CVG), index of individuality (II) and the RCV were calculated. RESULTS: Thirty-five patients with a combined 124 dd-cfDNA samples were included in the final analysis. The median dd-cfDNA was 0.31% (interquartile range 0.18%-0.68%), the 97.5th percentile and 95th percentile were 1.3% and 1.0%, respectively. In 30 stable patients with an average of 3.7 tests, the CVI was 25%, CVG 19%, II 1.33, and RCV 70%. CONCLUSION: In stable lung transplant patients, fluctuations in dd-cfDNA levels of up to 70% or levels less than 1% are within normal biological variation. With further validation, these thresholds may be incorporated into surveillance monitoring algorithms to identify potentially abnormal results indicating allograft dysfunction.

Donor-derived cell-free DNA as a composite marker of acute lung allograft dysfunction in clinical care.

BACKGROUND: As a marker of underlying lung allograft injury, donor-derived cell-free DNA (dd-cfDNA) may be used to identify episodes of acute allograft injury in lung transplant recipients. We investigated the utility of dd-cfDNA to monitor subjects at risk of acute rejection or infection in routine clinical practice. METHODS: This multicenter, retrospective cohort study collected data from lung transplant recipients within 3 years of transplant at 4 centers between March 24, 2020 and September 1, 2020. During this period, as part of routine care during the COVID-19 pandemic, these centers implemented a home-based surveillance program using plasma dd-cfDNA in preference to surveillance bronchoscopy. Dd-cfDNA was used to detect acute lung allograft dysfunction (ALAD) - a composite endpoint of acute rejection and infection. dd-cfDNA levels in patients with ALAD were compared to stable patients. The performance characteristics of dd-cfDNA ≥ 1.0% to detect ALAD were estimated. RESULTS: A total of 175 patients underwent 380 dd-cfDNA measurements, of which 290 were for routine surveillance purposes. dd-cfDNA was higher in patients with ALAD than stable patients (Median (IQR) 1.7% (0.63, 3.1) vs 0.35% (0.22, 0.79), p < 0.001). As an indication of underlying ALAD during surveillance testing, the estimated sensitivity of dd-cfDNA ≥1% was 73.9%, specificity of 87.7%, positive predictive value of 43.4% and negative predictive value of 96.5%. CONCLUSIONS: dd-cfDNA identified acute lung allograft dysfunction in asymptomatic lung transplant patients that may not have been identified by using a clinically indicated biopsy strategy alone. dd-cfDNA <1.0% may be useful in ruling out acute rejection and infection, supporting its use as a potential noninvasive marker for surveillance monitoring.

COVID-19 Vaccination is Associated With Favorable Outcomes Among Lung Transplant Patients With Breakthrough Infections.

BACKGROUND: There are limited data regarding the clinical efficacy of COVID-19 vaccines among lung transplant (LT) patients. METHODS: We included all LT patients diagnosed with COVID-19 between March 1, 2020, and December 10, 2021 (n = 84; median age 55, range, 20-73 years; males 65.5%). The study group was divided into 3 groups based on the vaccination status (patients who did not complete the primary series for any of the vaccines: n = 58; those with 2 doses of messenger RNA (mRNA) or 1 dose of the adenoviral vector vaccine, vaccinated group: n = 16; those with at least 1 additional dose beyond the primary series, boosted group: n = 10). RESULTS: Pulmonary parenchymal involvement on chest computed tomography scan was less common among the boosted group (P = .009). The proportion of patients with new or worsening respiratory failure was significantly lower among the vaccinated and boosted groups and these patients were significantly more likely to achieve the composite endpoint of oxygen-dependence free survival (P = .02). On multivariate logistic regression analysis, higher body mass index, restrictive lung disease as the transplant indication, and preinfection chronic lung allograft dysfunction were independently associated with acute or acute on chronic respiratory failure while being on therapeutic dose anticoagulation and having received the booster dose had a protective effect. CONCLUSION: COVID-19 vaccines appear to have several favorable effects among LT patients with breakthrough infections including lower likelihood of allograft involvement on imaging (among boosted patients), need of hospitalization, and complications such as new or worsening respiratory failure.

A Case Report of Breakthrough Infections With 2 SARS-CoV-2 Variants in a Lung Transplant Patient.

A lung transplant (LT) patient developed 2 distinct episodes of COVID-19, confirmed by whole-genome sequencing, which was caused by the Delta, and then followed 6 weeks later, by the Omicron variant. The clinical course with Omicron was more severe, leading us to speculate that Omicron may not be any milder among LT patients. We discuss the potential mechanisms behind the Omicron not being any milder among LT patients and emphasize the need for outcomes data among these patients. Until such data become available, it may be prudent to maintain clinical equipoise as regards the relative virulence of the newer variants among LT patients.

The molecular features of chronic lung allograft dysfunction in lung transplant airway mucosa.

BACKGROUND: Many lung transplants fail due to chronic lung allograft dysfunction (CLAD). We recently showed that transbronchial biopsies (TBBs) from CLAD patients manifest severe parenchymal injury and dedifferentiation, distinct from time-dependent changes. The present study explored time-selective and CLAD-selective transcripts in mucosal biopsies from the third bronchial bifurcation (3BMBs), compared to those in TBBs. METHODS: We used genome-wide microarray measurements in 324 3BMBs to identify CLAD-selective changes as well as time-dependent changes and develop a CLAD classifier. CLAD-selective transcripts were identified with linear models for microarray data (limma) and were used to build an ensemble of 12 classifiers to predict CLAD. Hazard models and random forests were then used to predict the risk of graft loss using the CLAD classifier, transcript sets associated with rejection, injury, and time. RESULTS: T cell-mediated rejection and donor-specific antibody were increased in CLAD 3BMBs but most had no rejection. Like TBBs, 3BMBs showed a time-dependent increase in transcripts expressed in inflammatory cells that was not associated with CLAD or survival. Also like TBBs, the CLAD-selective transcripts in 3BMBs reflected severe parenchymal injury and dedifferentiation, not inflammation or rejection. While 3BMBs and TBBs did not overlap in their top 20 CLAD-selective transcripts, many CLAD-selective transcripts were significantly increased in both for example LOXL1, an enzyme controlling matrix remodeling. In Cox models for one-year survival, the 3BMB CLAD-selective transcripts and CLAD classifier predicted graft loss and correlated with CLAD stage. Many 3BMB CLAD-selective transcripts were also increased by injury in kidney transplants and correlated with decreased kidney survival, including LOXL1. CONCLUSIONS: Mucosal and transbronchial biopsies from CLAD patients reveal a diffuse molecular injury and dedifferentiation state that impacts prognosis and correlates with the physiologic disturbances. CLAD state in lung transplants shares features with failing kidney transplants, indicating elements shared by the injury responses of distressed organs.

Dapsone as an Effective Treatment for Arthritis Secondary to Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a disorder of the terminal follicular epithelium in the apocrine sweat glands. Chronic relapsing inflammation, mucopurulent discharge, and progressive scarring frequently involving the axillary and inguinoperineal area characterize HS. Reactive arthritis is associated with chronic infections, such as HS, although joint involvement is uncommon. Treatment is based on the eradication of the underling infection. Whereas skin lesions may improve with antibiotic therapy, the arthritis of HS is often unresponsive to therapy. Various therapies have been tried in HS, including nonsteroidal antiinflammatory drugs, colchicine, mesalamine, dapsone, and TNF inhibitors. A case of severe, debilitating arthritis associated with HS that responded to dapsone is reported. This case demonstrates the difficulty of successful treatment of HS as well as of the associated arthritis.

Donor derived cell free DNA% is elevated with pathogens that are risk factors for acute and chronic lung allograft injury.

BACKGROUND: Acute and chronic forms of lung allograft injury are associated with specific respiratory pathogens. Donor-derived cell free DNA (ddcfDNA) has been shown to be elevated with acute lung allograft injury and predictive of long-term outcomes. We examined the %ddcfDNA values at times of microbial isolation from bronchoalveolar lavage (BAL). METHODS: Two hundred and six BAL samples from 51 Lung Transplant Recipients (LTRs) with concurrently available plasma %ddcfDNA were analyzed along with microbiology and histopathology. Microbial species were grouped into bacterial, fungal, and viral and "higher risk" and "lower risk" cohorts based on historical association with downstream allograft dysfunction. Analyses were performed to determine pathogen category association with %ddcfDNA, independent of inter-subject variability. RESULTS: Presence of microbial isolates in BAL was not associated with elevated %ddcfDNA compared to samples without isolates. However, "higher risk" bacterial and viral microbes showed greater %ddcfDNA values than lower risk species (1.19% vs. 0.65%, p < 0.01), independent of inter-subject variability. Histopathologic abnormalities concurrent with pathogen isolation were associated with higher %ddcfDNA compared to isolation episodes with normal histopathology (medians 1.23% and 0.66%, p = 0.05). Assessments showed no evidence of correlation between histopathology or bronchoscopy indication and presence of higher risk vs. lower risk pathogens. CONCLUSION: %ddcfDNA is higher among cases of microbial isolation with concurrent abnormal histopathology and with isolation of higher risk pathogens known to increase risk of allograft dysfunction. Future studies should assess if %ddcfDNA can be used to stratify pathogens for risk of CLAD and identify pathogen associated injury prior to histopathology.

Use of donor-derived-cell-free DNA as a marker of early allograft injury in primary graft dysfunction (PGD) to predict the risk of chronic lung allograft dysfunction (CLAD).

BACKGROUND: Primary graft dysfunction (PGD) is a risk factor for chronic lung allograft dysfunction (CLAD). However, the association between PGD and degree of allograft injury remains poorly defined. In this study, we leverage a novel biomarker for allograft injury, percentage donor-derived cell-free DNA (%ddcfDNA), to study the association between PGD, degree of allograft injury, and the development of CLAD. METHODS: This prospective cohort study recruited 99 lung transplant recipients and collected plasma samples on days 1, 3, and 7 for %ddcfDNA measurements. Clinical data on day 3 was used to adjudicate for PGD. %ddcfDNA levels were compared between PGD grades. In PGD patients, %ddcfDNA was compared between those who developed CLAD and those who did not. RESULTS: On posttransplant day 3, %ddcfDNA was higher in PGD than in non-PGD patients (median [IQR]: 12.2% [8.2, 22.0] vs 8.5% [5.6, 13.2] p = 0.01). %ddcfDNA correlated with the severity grade of PGD (r = 0.24, p = 0.02). Within the PGD group, higher levels of %ddcfDNA correlated with increased risk of developing CLAD (log OR(SE) 1.38 (0.53), p = 0.009). PGD patients who developed CLAD showed ∼2-times higher %ddcfDNA levels than patients who did not develop CLAD (median [IQR]: 22.4% [11.8, 27.6] vs 9.9% [6.7, 14.9], p = 0.007). CONCLUSION: PGD patients demonstrated increased early posttransplant allograft injury, as measured by %ddcfDNA, in comparison to non-PGD patients, and these high %ddcfDNA levels were associated with subsequent development of CLAD. This study suggests that %ddcfDNA identifies PGD patients at greater risk of CLAD than PGD alone.

Donor-derived cell-free DNA accurately detects acute rejection in lung transplant patients, a multicenter cohort study.

BACKGROUND: Acute rejection, which includes antibody-mediated rejection and acute cellular rejection, is a risk factor for lung allograft loss. Lung transplant patients often undergo surveillance transbronchial biopsies to detect and treat acute rejection before irreversible chronic rejection develops. Limitations of this approach include its invasiveness and high interobserver variability. We tested the performance of percent donor-derived cell-free DNA (%ddcfDNA), a non-invasive blood test, to detect acute rejection. METHODS: This multicenter cohort study monitored 148 lung transplant subjects over a median of 19.6 months. We collected serial plasma samples contemporaneously with TBBx to measure %ddcfDNA. Clinical data was collected to adjudicate for acute rejection. The primary analysis consisted of computing the area-under-the-receiver-operating-characteristic-curve of %ddcfDNA to detect acute rejection. Secondary analysis determined %ddcfDNA rule-out thresholds for acute rejection. RESULTS: ddcfDNA levels were high after transplant surgery and decayed logarithmically. With acute rejection, ddcfDNA levels rose six-fold higher than controls. ddcfDNA levels also correlated with severity of lung function decline and histological grading of rejection. %ddcfDNA area-under-the-receiver-operating-characteristic-curve for acute rejection, AMR, and ACR were 0.89, 0.93, and 0.83, respectively. ddcfDNA levels of <0.5% and <1.0% showed a negative predictive value of 96% and 90% for acute rejection, respectively. Histopathology detected one-third of episodes with ddcfDNA levels ≥1.0%, even though >90% of these events were coincident to clinical complications missed by histopathology. CONCLUSIONS: This study demonstrates that %ddcfDNA reliably detects acute rejection and other clinical complications potentially missed by histopathology, lending support to its use as a non-invasive marker of allograft injury.

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part III: Pharmacology, medical and surgical management of post-transplant extrapulmonary conditions statements.

Patients with connective tissues disease (CTD) are often on immunomodulatory agents before lung transplantation (LTx). Till now, there's no consensus on the safety of using these agents perioperative and post-transplant. The International Society for Heart and Lung Transplantation-supported consensus document on LTx in patients with CTD addresses the risk and contraindications of perioperative and post-transplant management of the biologic disease-modifying antirheumatic drugs (bDMARD), kinase inhibitor DMARD, and biologic agents used for LTx candidates with underlying CTD, and the recommendations and management of non-gastrointestinal extrapulmonary manifestations, and esophageal disorders by medical and surgical approaches for CTD transplant recipients.