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Cumulative epithelial injuries after lung transplantation (LT) play a major role in CLAD pathogenesis. Epithelial club cells are specifically depleted in CLAD. We hypothesized that club cell apoptosis occurs in CLAD and at an earlier injury stage during B-grade airway-centered ACR. Lung biopsies were collected at the time of retransplantation from 20 consecutive patients undergoing a second LT for CLAD and from 13 control lungs (4 excess donor lung tissues, 9 lobectomies). Transbronchial biopsies (TBB) and bronchoalveolar lavage (BAL) were obtained from LT patients (post first bilateral LT 2010-2015) at the time of B-grade ACR =0 or ≥1 (categorized as stable or unstable based on a concurrent >10% drop in lung function), within 25 months post-LT. Biopsies were immunostained with antibodies for epithelial cells (Pan-cytokeratin), club cells (club cell secretory protein, CCSP) and a cell death detection kit for Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) to detect apoptotic cells. M30 and M65, fragments of cytokeratin-18 released during epithelial cell apoptosis and total cell death, respectively, were measured in the BAL using ELISA. Compared to controls, CLAD lungs had a significantly higher frequency of apoptotic cells (p=0.02) and a higher frequency of apoptotic club cells (p=0.08) (figure 1A-C). Club cell frequency was lower in TBBs from unstable ≥B1 ACR patients compared to stable (p=0.10) (figure 1D). However, a drop in lung function occurring at the time of ≥B1 ACR showed no association with frequency of apoptotic epithelial cells, apoptotic club cells, or the concentration of M30 or M65 in the BAL. Increased epithelial cell apoptosis were observed in lungs affected by CLAD but were not identified during airway ACR, possibly due to the earlier phase of the inflammatory process or potential sampling error of the small biopsies. Further study is needed to understand the timing of epithelial cell injury and death in CLAD pathogenesis. [ABSTRACT FROM AUTHOR]

Chronic lung allograft dysfunction (CLAD) is the major barrier to long-term survival following lung transplantation and results from repeated acute injuries to the graft epithelium. Epithelial club cells are known to have protective, anti-inflammatory, and regenerative roles and are depleted in CLAD. Mechanisms driving club cell loss in CLAD are unknown. Our single cell RNA sequencing (scRNAseq) data showed that TRAIL transcript was upregulated in CLAD club cells compared to control donor lung club cells. TRAIL induces apoptotic cell death by binding to its receptors (TRAIL-R1 and TRAIL-R2). To validate the scRNAseq data, we here further investigate the expression of TRAIL and its receptors at the protein level. We hypothesized that CLAD develops as a consequence of club cell death induced by TRAIL signaling during episodes of acute lung allograft dysfunction (ALAD). Lung transplant recipients' (LTR) airway brushings were obtained 3-12 months post-LT and processed for flow cytometry. TRAIL, TRAIL-R1, TRAIL-R2 expression was examined in club cells in LTRs with or without ALAD, defined as a >=10% drop in forced expiratory volume in 1 second from prior. After exclusion of non-epithelial cells, EpCAM+ epithelial cells and EpCAM+CCSP+ club cells were identified. Our findings show that the frequencies of both TRAIL+ club cells and TRAIL+ non-club epithelial cells were significantly higher in ALAD LTRs compared to non-ALAD LTRs (Fig. 1A-C). Further, TRAIL-R1 expression on club and non-club epithelial cells tended to be higher in ALAD compared to non-ALAD LTRs (Fig. 1A, D-E). TRAIL-R2 expression did not differ between ALAD and non-ALAD LTRs. Our preliminary data show an upregulation of TRAIL within epithelial cells found in ALAD airway brushings compared to control. The co-localization of TRAIL and TRAIL-R1 in club cell suggests that autocrine or paracrine cell death might be potential mechanisms for club cell loss in CLAD. [ABSTRACT FROM AUTHOR]

T cells are the primary driver of ACR-associated immune responses following lung transplantation (LTx) and may mediate the progression of ACR to Chronic Lung Allograft Dysfunction (CLAD). We previously reported that the CD8+, but not regulatory, T cell content of first grade A1 transbronchial biopsies (TBBs) from stable patients was related to future CLAD. Here, we used IMC, a technique that enables highly multiplexed tissue imaging and acquisition of single-cell data, to identify intragraft T cell phenotypes that may be associated with subsequent CLAD. Patients with a first episode of A1B0 ACR, who remained CLAD-free for at least 5 years (n=3) or who developed CLAD within 2 years (n=3) following LTx were selected. TBBs were sectioned and stained with 35 heavy metal-conjugated antibodies including both lineage-defining and functional markers. For each sample, four regions of interest (ROI) measuring 800 mm2 were laser ablated. Raw data was analyzed using QuPath and HistoCAT. Co-expression of markers was used to identify cell phenotypes. t-SNE was used to plot single-cell data in two dimensions. PhenoGraph was used to identify 37 cell clusters based on antibody binding similarity as represented on a heatmap (Figure 1A), highlighted on the t-SNE plot (Figure 1B). Antibody binding patterns were visualized and cell clusters were mapped back to future CLAD/CLAD-free ROIs and highlighted on constructed images (Figure 1C, D). The ratio of CD45RO+CD8+CD27+ T cells (Cluster 7) to total cells was significantly increased in the future CLAD group (p=0.006) (Figure 1E). In keeping with our prior observations, there was no significant difference in the proportion of CD45RO+CD4+FOXP3+ T cells (Cluster 33) (Figure 1F). These results suggest that in asymptomatic patients with a first episode of A1 rejection, greater memory CD8+ T cell content may be of prognostic importance, possibly indicating poorer long-term outlook. Validation in additional patients is underway. [ABSTRACT FROM AUTHOR]

Survival after lung transplantation (LTx) still remains limited by chronic lung allograft dysfunction (CLAD). Prior studies showed an association between graft cellular expression of the checkpoint HLA-G and acceptance, whereas conversely, soluble HLA-G (sHLA-G) in plasma/BAL was associated with acute rejection. We investigated whether plasma levels of extra-vesicular (EVs)-bound HLA-G could predict CLAD. We used data for 79 LTx recipients from COLT (Cohort For Lung Transplantation) cohortwith ≥1 available blood samples at 6-, or 12-months post-Tx, all with a stable function within the 1st year. Among them, 41 developed subsequent CLAD (Group CLAD=33 BOS and 8 RAS) and 38 remained STABLE at 3 years. 20 heathy individuals (HI) were negative controls. EVs from plasma were isolated by size exclusion chromatography and characterized by nanoparticule tracking analysis. Plasma levels of EVs-bound HLA-G (sHLA-G EV) and of total soluble-HLA-G (sHLA-G TOT =sHLA-G EV + free sHLA-G) were measured by ELISA. Uni- and multivariate were performed to assess association of EVs levels and CLAD/survival. In stable patients, mean plasma levels of sHLA-G EV at M6 and M12, were significantly increased as compared to those of HI (M6: 30.2 vs 15,1 ng/mL, p=0.008, and M12: 37.8 vs 15.1 ng/mL, p=0.0009, respectively). In BOS patients, a decreased plasma levels of sHLA-G EV were observed at M6 and M12 as compared to stable patients, with a significant difference at M12 (mean sHLA-G EV of 23.7 ng/mL vs 38.7 p=0.02). In those BOS patients, sHLA-G EV levels remained increased as compared to HI at M6 (p=0.01). In RAS patients, sHLA- GEV levels was similar to stable patients at M6 and M12, and increased as compared to HI (M12: 40,5 vs 15,6 ng/mL, p=0.004). Among the whole cohort, a higher freedom from CLAD was observed in patients with sHLA-G EV level > first IQR (=21.3 g/ml) at M12 post-LTx (p=0.01, Figure 1). Our data suggest that an early decrease of sHLA-G EV levels after LTx may be predictive of subsequent CLAD onset. [ABSTRACT FROM AUTHOR]

Long-term survival after lung transplantation remains limited by chronic lung allograft dysfunction (CLAD), with 2 main phenotypes: bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). We aimed to assess CLAD lung allografts using imaging mass cytometry (IMC), a high dimensional tissue imaging system allowing a multiparametric in situ exploration at a single cell level. Four BOS, 4 RAS, and 4 control lung samples were stained with 35 heavy metal-tagged antibodies selected to assess structural and immune proteins of interest. We identified 50 immune and non-immune cell clusters. CLAD lungs had significantly reduced club cells. A Ki67-high basal cell population was mostly present in RAS and in proximity to memory T cells. Memory CD8 + T cells were more frequent in CLAD lungs, regulatory T cells more prominent in RAS. IMC is a powerful technology for detailed cellular analysis within intact organ structures that may shed further light on CLAD mechanisms., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Long-term survival after lung transplantation (LTx) remains limited by chronic lung allograft dysfunction (CLAD), which includes 2 main phenotypes: bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS), with possible overlap. We aimed to detail and quantify pathological features of these CLAD sub-types., Methods: Peripheral and central paraffin-embedded explanted lung samples were obtained from 20 consecutive patients undergoing a second LTx for CLAD, from 3 lobes. Thirteen lung samples, collected from non-transplant lobectomies or donor lungs, were used as controls. Blinded semi-quantitative grading was performed to assess airway fibrotic changes, parenchymal and pleural fibrosis, and epithelial and vascular abnormalities., Results: CLAD lung samples had higher scores for all airway- and lung-related parameters compared to controls. There was a notable overlap in histologic scores between BOS and RAS, with a wide range of scores in both conditions. Parenchymal and vascular fibrosis scores were significantly higher in RAS compared to BOS (p = 0.003 for both). We observed a significant positive correlation between the degree of inflammation around each airway, the severity of epithelial changes, and airway fibrosis. Immunofluorescence staining demonstrated a trend toward a lower frequency of club cells in CLAD and a higher frequency of apoptotic club cells in BOS samples (p = 0.01)., Conclusions: CLAD is a spectrum of airway, parenchymal, and pleural fibrosis, as well as epithelial, vascular, and inflammatory pathologic changes, where BOS and RAS overlap significantly. Our semi-quantitative grading score showed a generally high inter-reader reliability and may be useful for future CLAD histologic assessments., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: T cells drive acute cellular rejection (ACR) and its progression to chronic lung allograft dysfunction (CLAD) following lung transplantation. International Society for Heart and Lung Transplantation grade A1 ACR without associated allograft dysfunction is often untreated, yet some patients develop progressive graft dysfunction. T-cell composition of A1 ACR lesions may have prognostic value; therefore, protein-level and epigenetic techniques were applied to transbronchial biopsy tissue to determine whether differential T-cell infiltration in recipients experiencing a first episode of stable grade A1 ACR (StA1R) is associated with early CLAD., Methods: Sixty-two patients experiencing a first episode of StA1R were divided into those experiencing CLAD within 2 years (n = 13) and those remaining CLAD-free for 5 or more years (n = 49). Imaging mass cytometry (IMC) was used to profile the spectrum and distribution of intragraft T cell phenotypes on a subcohort (n = 16; 8 early-CLAD and 8 no early-CLAD). Immunofluorescence was used to quantify CD4 + , CD8 + , and FOXP3 + cells. Separately, CD3 + cells were fluorescently labeled, micro-dissected, and the degree of Treg-specific demethylated region methylation was determined., Results: PhenoGraph unsupervised clustering on IMC revealed 50 unique immune cell subpopulations. Methylation and immunofluorescence analyses demonstrated no significant differences in Tregs between early-CLAD and no early-CLAD groups. Immunofluorescence revealed that patients who developed CLAD within 2 years of lung transplantation showed greater CD8 + T cell infiltration compared to those who remained CLAD-free for 5 or more years., Conclusions: In asymptomatic patients with a first episode of A1 rejection, greater CD8 + T cell content may be indicative of worse long-term outlook., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Circulating extracellular vesicles (EVs) have shown promising results as noninvasive biomarkers for predicting disease outcomes in solid organ transplantation. Because in situ graft cell expression of the tolerogenic molecule HLA-G is associated with acceptance after lung transplantation (LTx), we hypothesized that plasma EV-bound HLA-G (HLA-GEV) levels could predict chronic lung allograft dysfunction (CLAD) development., Methods: We analyzed 78 LTx recipients from the Cohort-for-Lung-Transplantation cohort, all in a stable (STA) state within the first year post-LTx. At 3 y, 41 patients remained STA, and 37 had CLAD (bronchiolitis obliterans syndrome, BOS, [n = 32] or restrictive allograft syndrome [n = 5]). HLA-GEV plasma levels were measured at month 6 (M6) and M12 in 78 patients. CLAD occurrence and graft failure at 3 y post-LTx were assessed according to early HLA-GEV plasma levels., Results: In patients with subsequent BOS, (1) HLA-GEV levels at M12 were significantly lower than those in STA patients (P = 0.013) and (2) also significantly lower than their previous levels at M6 (P = 0.04).A lower incidence of CLAD and BOS and higher graft survival at 3 y were observed in patients with high HLA-GEV plasma levels at M12 (high versus low HLA-GEVs patients [cutoff 21.3 ng/mL]: freedom from CLAD, P = 0.002; freedom from BOS, P < 0.001; and graft survival, P = 0.04, [log-rank]). Furthermore, in multivariate analyses, low HLA-GEV levels at M12 were independently associated with a subsequent risk of CLAD, BOS, and graft failure at 3 y (P = 0.015, P = 0.036, and P = 0.026, respectively [Cox models])., Conclusions: This exploratory study suggests the potential of EV-bound HLA-G plasma levels as a liquid biopsy in predicting CLAD/BOS onset and subsequent graft failure., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The main limitation to long-term lung transplant (LT) survival is chronic lung allograft dysfunction (CLAD), which leads to irreversible lung damage and significant mortality. Individual factors can impact CLAD, but no large genetic investigation has been conducted to date. We established the multicentric Genetic COhort in Lung Transplantation (GenCOLT) biobank from a rich and homogeneous sub-part of COLT cohort. GenCOLT collected DNA, high-quality GWAS (genome-wide association study) genotyping and robust HLA data for donors and recipients to supplement COLT clinical data. GenCOLT closely mirrors the global COLT cohort without significant variations in variables like demographics, initial disease and survival rates (P > 0.05). The GenCOLT donors were 45 years-old on average, 44% women, and primarily died of stroke (54%). The recipients were 48 years-old at transplantation on average, 45% women, and the main underlying disease was chronic obstructive pulmonary disease (45%). The mean follow-up time was 67 months and survival at 5 years was 57.3% for the CLAD subgroup and 97.4% for the non-CLAD subgroup. After stringent quality controls, GenCOLT gathered more than 7.3 million SNP and HLA genotypes for 387 LT pairs, including 91% pairs composed of donor and recipient of European ancestry. Overall, GenCOLT is an accurate snapshot of LT clinical practice in France and Belgium between 2009 and 2018. It currently represents one of the largest genetic biobanks dedicated to LT with data available simultaneously for donors and recipients. This unique cohort will empower to run comprehensive GWAS investigations of CLAD and other LT outcomes., (© 2024. The Author(s).)

BACKGROUND Lung transplantation (LTx) is a life-extending therapy for specific patients with terminal lung diseases. This study aimed to evaluate the associations and causes of 1-year mortality after lung transplantation at Strasbourg University Hospital, France, between 2012 and 2021. MATERIAL AND METHODS We carried out a retrospective analysis on 425 patients who underwent LTx at Strasbourg University Hospital between January 1, 2012, and December 31, 2021. Pre-transplant, perioperative, and postoperative data were collected from the electronic medical records. RESULTS Among all patients, 94.6% had a LTx, 4.0% a heart-lung transplantation, and 1.4% underwent pancreatic islet-lung transplantation. The median age at transplantation was 57 years, with 55.3% male patients. The main native lung disease leading to LTx was chronic obstructive pulmonary disease in 51.1% of patients; 16.2% needed super-urgent LTx. The 1-year mortality rate was 11.5%. Most deaths were either caused by multi-organ failure or septic shock. In our multivariate analysis, we identified 3 risk factors significantly related to 1-year mortality after LTx: body mass index (BMI) between 25 and 30 kg/m² vs BMI between 18.5 and 25 kg/m² (P=0.032), postoperative extracorporeal membrane oxygenation support (P=0.034), and intensive care unit length of stay after transplantation (P<0.001). Two other factors were associated with a significantly lower 1-year mortality risk: longer hospital stay after LTx (P=0.024) and tacrolimus prescription (P=0.004). CONCLUSIONS Our study reported a 1-year mortality rate of 11.5% after LTx. Although LTx candidates are carefully selected, additional data are required to improve understanding of the risk factors for post-LTx mortality.

Although cytomegalovirus (CMV) viremia/DNAemia has been associated with reduced survival after lung transplantation, its association with chronic lung allograft dysfunction (CLAD) and its phenotypes is unclear. We hypothesized that, in a modern era of CMV prophylaxis, CMV DNAemia would still remain associated with death, but also represent a risk factor for CLAD and specifically restrictive allograft syndrome (RAS)/mixed phenotype. This was a single-center retrospective cohort study of all consecutive adult, first, bilateral-/single-lung transplants done between 2010-2016, consisting of 668 patients. Risks for death/retransplantation, CLAD, or RAS/mixed, were assessed by adjusted cause-specific Cox proportional-hazards models. CMV viral load (VL) was primarily modeled as a categorical variable: undetectable, detectable to 999, 1000 to 9999, and ≥10 000 IU/mL. In multivariable models, CMV VL was significantly associated with death/retransplantation (≥10 000 IU/mL: HR = 2.65 [1.78-3.94]; P < .01), but was not associated with CLAD, whereas CMV serostatus mismatch was (D+R-: HR = 2.04 [1.30-3.21]; P < .01). CMV VL was not associated with RAS/mixed in univariable analysis. Secondary analyses with a 7-level categorical or 4-level ordinal CMV VL confirmed similar results. In conclusion, CMV DNAemia is a significant risk factor for death/retransplantation, but not for CLAD or RAS/mixed. CMV serostatus mismatch may have an impact on CLAD through a pathway independent of DNAemia., Competing Interests: Declaration of competing interest The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Due to the COVID-19 pandemic, France underwent several lockdown periods during 2020. Our aim was to evaluate its clinical and social impact on lung transplant (LT) patients treated at Strasbourg University Hospital, by comparing three periods: first lockdown (T1: March-May 2020), end of the first lockdown (T2: May-October 2020), and second lockdown (T3: November-December 2020) and the incidence of COVID-19 infections. A cohort of patients with rare lung disease (RLD) was also studied during T2., Methods: We used clinical and paraclinical data collected during routine follow-up. A questionnaire was submitted to each patient at each period to assess their lifestyle, adherence to protective measures against COVID-19, contacts with their family and friends, and contagion risk. The incidence of new COVID-19 cases was also assessed., Results: Overall, 283 LT and 57 RLD patients were included. We observed only eight COVID-19 cases over the three periods (n = 4 during T1, n = 0 during T2, and n = 4 during T3) in LT patients, with 37.5 % of patients hospitalized, no ICU transfers, and 100 % favorable outcomes. No case of COVID-19 was diagnosed in the RLD cohort. When comparing the three periods in the LT group, fewer patients limited their out-of-home activities during T2 (p < 0.0001). The frequency of these activities increased after the first lockdown, for the purchase of basic necessities (p < 0.0001), and professional activity continued (p = 0.008). We observed a significant increase in unscheduled medical consultations and in the prescription of anti-infective treatments during the end of the lockdown (p = 0.0002 and p = 0.005, respectively). Adherence to lockdown and to protective measures was high in both groups of patients., Conclusion: COVID-19 incidence remained low in both groups and there were significant lifestyle evolutions in LT patients and in those with RLD between first and second lockdown., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Cystic fibrosis related diabetes (CFRD) is commonly associated with declining lung function and nutritional status. We aimed to evaluate the pulmonary impact of early glucose abnormalities by using 2-h standard oral glucose tolerance testing (OGTT) and continuous glucose monitoring (CGM) in people with cystic fibrosis (PwCF)., Methods: PwCF aged ≥10 years old without known CFRD were included in a five-year prospective multicentre study. Annual evaluation of nutritional status, lung function, OGTT and CGM was set up. Associations between annual rate changes (Δ) in lung function, ΔFEV1 (forced expiratory volume in 1 s) percentage predicted (pp) and ΔFVC (forced vital capacity) pp., and annual rate changes in OGTT or CGM variables were estimated with a mixed model with a random effect for subject., Results: From 2009 to 2016, 112 PwCF (age: 21 ± 11 years, BMI (body mass index) z-score: -0.55 ± 1.09, FEV1pp: 77 ± 24 %, 2-h OGTT glucose: 122 ± 44 mg/dL, AUC (area under curve) >140 mg/dL: 1 mg/dL/day (0.2, 3.0) were included. A total of 428 OGTTs and 480 CGMs were collected. The participants presented annual decline of FVCpp and FEV1pp at -1.0 % per year (-1.6, -0.4), p < 0.001 and - 1.9 % per year (-2.5, -1.3), p < 0.001 respectively without change in BMI z-score during the study. Variation of two-hour OGTT glucose was not associated with declining lung function, as measured by ΔFEV1pp (p = 0.94) and ΔFVCpp (p = 0.90). Among CGM variables, only increase in AUC >140 mg/dL between two annual visits was associated with a decrease in ΔFVCpp (p < 0.05) and ΔFEV1pp (p < 0.05)., Conclusions: This prospective study supports the fact that early glucose abnormalities revealed by CGM predict pulmonary function decline in PwCF, while 2-h standard OGTT glucose is not associated with pulmonary impairment., Competing Interests: Declaration of competing interest No potential conflicts of interest relevant to this article were reported., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Long-term outcomes of lung transplantation (LTx) remain hampered by chronic lung allograft dysfunction (CLAD). Matrix metalloproteinase 9 (MMP-9) is a secretory endopeptidase identified as a key mediator in fibrosis processes associated with CLAD. The objective of this study was to investigate whether plasma MMP9 levels may be prognostic of CLAD development., Methods: Participants were selected from the Cohort in Lung Transplantation (COLT) for which a biocollection was associated. We considered two time points, year 1 (Y1) and year 2 (Y2) post-transplantation, for plasma MMP-9 measurements. We analysed stable recipients at those time points, comparing those who would develop a CLAD within the 2 years following the measurement to those who would remain stable 2 years after., Results: MMP-9 levels at Y1 were not significantly different between the CLAD and stable groups (230 ng/ml vs. 160 ng/ml, p = 0.4). For the Y2 analysis, 129 recipients were included, of whom 50 developed CLAD within 2 years and 79 remained stable within 2 years. MMP-9 plasma median concentrations were higher in recipients who then developed CLAD than in the stable group (230 ng/ml vs. 118 ng/ml, p = 0.003). In the multivariate analysis, the Y2 MMP-9 level was independently associated with CLAD, with an average increase of 150 ng/ml (95% CI [0-253], p = 0.05) compared to that in the stable group. The Y2 ROC curve revealed a discriminating capacity of blood MMP-9 with an area under the curve of 66%., Conclusion: Plasmatic MMP-9 levels measured 2 years after lung transplantation have prognostic value for CLAD., (© 2024. The Author(s).)

Background: Airway epithelial injury is thought to be a key event in the pathogenesis of chronic lung allograft dysfunction (CLAD). We investigated whether markers of epithelial activity and injury in bronchoalveolar lavage fluid (BAL) correlate with CLAD diagnosis and major CLAD phenotypes: bronchiolitis obliterans syndrome (BOS) vs restrictive allograft syndrome (RAS)-related phenotypes (including RAS, mixed phenotype, and all other patients with RAS-like opacities)., Methods: CLAD status and phenotypes were retrospectively determined in a cohort of all consecutive adult, first, bilateral lung transplants performed 2010-2015, with available BAL samples. All patients with RAS-related phenotypes were included and 1:1 matched with BOS patients based on the time from transplant to CLAD-onset. Subjects who were CLAD-free for a minimum of 3 years post-transplant were 1:1 matched to CLAD patients and included as controls. Proteins that maintain the barrier function of the airway epithelial mucosa (club cell secretory protein, surfactant protein-D and epithelial mucins: MUC1, MUC5AC, MUC5B, MUC16), as well as epithelial cell death markers (M30&M65 representing epithelial cell apoptosis and overall death, respectively), were measured in BAL obtained within 6-months post CLAD onset using a double-sandwich ELISA or a multiplex bead assay. Protein levels were compared using Mann-Whitney-U-test. Association between protein levels and graft survival was assessed using Cox proportional hazards models, adjusted for CMV serology mismatch status and CLAD phenotype., Results: Fifty-four CLAD (27 BOS, 11 RAS, 7 mixed, 9 others with RAS-like opacities) patients and 23 CLAD-free controls were included. Median BAL levels were significantly higher in patients with CLAD compared to CLAD-free controls for M30 (124.5 vs 88.7 U/L), MUC1 (6.8 vs 3.2 pg/mL), and MUC16 (121.0 vs 30.1 pg/mL). When comparing CLAD phenotypes, M30 was significantly higher in patients with RAS-related phenotypes than BOS (160.9 vs 114.6 U/L). In multivariable models, higher M30 and MUC5B levels were associated with decreased allograft survival after CLAD onset independent of phenotype (p < 0.05 for all)., Conclusions: Airway epithelial mucins and cell death markers are enhanced in the BAL of patients with CLAD and can assist in differentiating between CLAD phenotypes and post-CLAD outcomes. Abnormal airway mucin expression and epithelial cell death may be involved in the pathogenesis of CLAD, and therefore their detection may aid in future selection of targeted therapies., (Copyright © 2023 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Chronic lung allograft dysfunction (CLAD) is the leading cause of poor long-term survival after lung transplantation (LT). Systems prediction of Chronic Lung Allograft Dysfunction (SysCLAD) aimed to predict CLAD., Methods: To predict CLAD, we investigated the clinicome of patients with LT; the exposome through assessment of airway microbiota in bronchoalveolar lavage cells and air pollution studies; the immunome with works on activation of dendritic cells, the role of T cells to promote the secretion of matrix metalloproteinase-9, and subpopulations of T and B cells; genome polymorphisms; blood transcriptome; plasma proteome studies and assessment of MSK1 expression., Results: Clinicome: the best multivariate logistic regression analysis model for early-onset CLAD in 422 LT eligible patients generated a ROC curve with an area under the curve of 0.77. Exposome: chronic exposure to air pollutants appears deleterious on lung function levels in LT recipients (LTRs), might be modified by macrolides, and increases mortality. Our findings established a link between the lung microbial ecosystem, human lung function, and clinical stability post-transplant. Immunome: a decreased expression of CLEC1A in human lung transplants is predictive of the development of chronic rejection and associated with a higher level of interleukin 17A; Immune cells support airway remodeling through the production of plasma MMP-9 levels, a potential predictive biomarker of CLAD. Blood CD9-expressing B cells appear to favor the maintenance of long-term stable graft function and are a potential new predictive biomarker of BOS-free survival. An early increase of blood CD4 + CD57 + ILT2+ T cells after LT may be associated with CLAD onset. Genome: Donor Club cell secretory protein G38A polymorphism is associated with a decreased risk of severe primary graft dysfunction after LT. Transcriptome: blood POU class 2 associating factor 1, T-cell leukemia/lymphoma domain, and B cell lymphocytes, were validated as predictive biomarkers of CLAD phenotypes more than 6 months before diagnosis. Proteome: blood A2MG is an independent predictor of CLAD, and MSK1 kinase overexpression is either a marker or a potential therapeutic target in CLAD., Conclusion: Systems prediction of Chronic Lung Allograft Dysfunction generated multiple fingerprints that enabled the development of predictors of CLAD. These results open the way to the integration of these fingerprints into a predictive handprint., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pison, Tissot, Bernasconi, Royer, Roux, Koutsokera, Coiffard, Renaud-Picard, Le Pavec, Mordant, Demant, Villeneuve, Mornex, Nemska, Frossard, Brugière, Siroux, Marsland, Foureau, Botturi, Durand, Pellet, Danger, Auffray, Brouard, Nicod, Magnan and Members of the COhort of Lung Transplantation and Systems prediction of Chronic Lung Allograft Dysfunction consortia.)

Question Addressed by the Study: Do three coronavirus disease 2019 (COVID-19) vaccine doses induce a serological response in lung transplant recipients?, Methods: We retrospectively included 1071 adults (551 (52%) males) at nine transplant centres in France. Each had received three COVID-19 vaccine doses in 2021, after lung transplantation. An anti-spike protein IgG response, defined as a titre >264 BAU·mL -1 after the third dose (median (interquartile range (IQR)) 3.0 (1.7-4.1) months), was the primary outcome and adverse events were the secondary outcomes. Median (IQR) age at the first vaccine dose was 54 (40-63) years and median (IQR) time from transplantation to the first dose was 64 (30-110) months., Results: Median (IQR) follow-up after the first dose was 8.3 (6.7-9.3) months. A vaccine response developed in 173 (16%) patients. Factors independently associated with a response were younger age at vaccination, longer time from transplantation to vaccination and absence of corticosteroid or mycophenolate therapy. After vaccination, 51 (5%) patients (47 non-responders (47/898 (5%)) and four (4/173 (2%)) responders) experienced COVID-19, at a median (IQR) of 6.6 (5.1-7.3) months after the third dose. No responders had severe COVID-19 compared with 15 non-responders, including six who died of the disease., Conclusions: Few lung transplant recipients achieved a serological response to three COVID-19 vaccine doses, indicating a need for other protective measures. Older age and use of mycophenolate or corticosteroids were associated with absence of a response. The low incidence of COVID-19 might reflect vaccine protection via cellular immunity and/or good adherence to shielding measures., Competing Interests: Conflict of interest: None for any authors., (Copyright ©The authors 2023.)

Lung transplantation (LTx) is the last-resort treatment for end-stage respiratory insufficiency, whatever its origin, and represents a steadily expanding field of endeavor. Major developments have been impelled over the years by painstaking efforts at LTx centers to improve donor and recipient selection, and multifaceted attempts have been made to meet the challenges raised by surgical management, perioperative care, and long-term medical complications. The number of procedures has increased, leading to improved post-LTx prognosis. One consequence of these multiple developments has been a pruning away of contraindications over time, which has, in some ways, complicated the patient selection process. With these considerations in mind, the Francophone Pulmonology Society (Société de Pneumology de Langue Française [SPLF]) has set up a task force to produce up-to-date working guidelines designed to assist pulmonologists in managing end-stage respiratory insufficiency, determining which patients may be eligible for LTx, and appropriately timing LTx-center referral. The task force has examined the most recent literature and evaluated the risk factors that continue to limit patient survival after LTx. Ideally, the objectives of LTx are to prolong life while improving quality of life. The guidelines developed by the task force apply to a limited resource and are consistent with the ethical principles described below., (Copyright © 2022 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Background: Lung transplant recipients experience episodes of immune-mediated acute lung allograft dysfunction (ALAD). ALAD episodes are a risk factor for chronic lung allograft dysfunction (CLAD), the major cause of death after lung transplantation. Our objective was to determine key cellular elements in dysfunctional lung allografts, with a focus on macrophages., Methods: We have applied single-cell RNA sequencing (scRNAseq) to bronchoalveolar lavage cells from stable and ALAD patients and to cells from explanted CLAD lung tissue., Results: We identified 2 alveolar macrophage (AM) subsets uniquely represented in ALAD. Using pathway analysis and differentially expressed genes, we annotated these as pro-inflammatory interferon-stimulated gene (ISG) and metallothionein-mediated inflammatory (MT) AMs. Functional analysis of an independent set of AMs in vitro revealed that ALAD AMs exhibited a higher expression of CXCL10, a marker of ISG AMs, and increased secretion of pro-inflammatory cytokines compared to AMs from stable patients. Using publicly available bronchoalveolar lavage scRNAseq datasets, we found that ISG and MT AMs are associated with more severe inflammation in COVID-19 patients. Analysis of cells from 4 explanted CLAD lungs revealed similar macrophage populations. Donor and recipient cells were identified using expressed single nucleotide variations. We demonstrated contributions of donor and recipient cells to all AM subsets early post-transplant, with loss of donor-derived cells over time., Conclusions: Our data reveal extensive heterogeneity among lung macrophages after lung transplantation and indicates that specific sub-populations may be associated with allograft dysfunction, raising the possibility that these cells may represent important therapeutic targets., (Copyright © 2022 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)