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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]

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: Children with advanced pulmonary disease due to cystic fibrosis (CF) are at risk of acute respiratory failure due to pulmonary exacerbations leading to their admission to pediatric intensive care units (PICU). The objectives of this study were to determine short and medium-term outcomes of children with CF admitted to PICU for acute respiratory failure due to pulmonary exacerbation and to identify prognosis factors., Methods: This retrospective monocentric study included patients less than 18 years old admitted to the PICU of a French university hospital between 2000 and 2020. Cox proportional hazard regression methods were used to determine prognosis factors of mortality or lung transplant., Results: Prior to PICU admission, the 29 patients included (median age 13.5 years) had a severe lung disease (median Forced Expiratory Volume in 1 s percentage predicted at 29%). Mortality rates were respectively 17%, 31%, 34%, 41% at discharge and at 3, 12 and 36 months post-discharge. Survival rates free of lung transplant were 34%, 32%, 24% and 17% respectively. Risk factors associated with mortality or lung transplant using the univariate analysis were female sex and higher pCO2 and chloride levels at PICU admission, and following pre admission characteristics: home respiratory and nutritional support, registration on lung transplant list and Stenotrophomonas Maltophilia bronchial colonization., Conclusion: Children with CF admitted to PICU for acute respiratory failure secondary to pulmonary exacerbations are at high risk of death, both in the short and medium terms. Lung transplant is their main chance of survival and should be considered early., (© 2024. The Author(s).)

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: Human cytomegalovirus (HCMV) infection is common and often severe in lung transplant recipients (LTRs), and it is a risk factor associated with chronic lung allograft dysfunction (CLAD). The complex interplay between HCMV and allograft rejection is still unclear. Currently, no treatment is available to reverse CLAD after diagnosis, and the identification of reliable biomarkers that can predict the early development of CLAD is needed. This study investigated the HCMV immunity in LTRs who will develop CLAD., Methods: This study quantified and phenotyped conventional (HLA-A2pp65) and HLA-E-restricted (HLA-EUL40) anti-HCMV CD8 + T (CD8 T) cell responses induced by infection in LTRs developing CLAD or maintaining a stable allograft. The homeostasis of immune subsets (B, CD4T, CD8 T, NK, and γδT cells) post-primary infection associated with CLAD was also investigated., Results: At M18 post-transplantation, HLA-EUL40 CD8 T responses were less frequently found in HCMV + LTRs (21.7%) developing CLAD (CLAD) than in LTRs (55%) keeping a functional graft (STABLE). In contrast, HLA-A2pp65 CD8 T was equally detected in 45% of STABLE and 47.8% of CLAD LTRs. The frequency of HLA-EUL40 and HLA-A2pp65 CD8 T among blood CD8 T cells shows lower median values in CLAD LTRs. Immunophenotype reveals an altered expression profile for HLA-EUL40 CD8 T in CLAD patients with a decreased expression for CD56 and the acquisition of PD-1. In STABLE LTRs, HCMV primary infection causes a decrease in B cells and inflation of CD8 T, CD57 + /NKG2C + NK, and δ2 - γδT cells. In CLAD LTRs, the regulation of B, total CD8 T, and δ2 + γδT cells is maintained, but total NK, CD57 + /NKG2C + NK, and δ2 - γδT subsets are markedly reduced, while CD57 is overexpressed across T lymphocytes., Conclusions: CLAD is associated with significant changes in anti-HCMV immune cell responses. Our findings propose that the presence of dysfunctional HCMV-specific HLA-E-restricted CD8 T cells together with post-infection changes in the immune cell distribution affecting NK and γδT cells defines an early immune signature for CLAD in HCMV + LTRs. Such a signature may be of interest for the monitoring of LTRs and may allow an early stratification of LTRs at risk of CLAD., 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 Rousselière, Delbos, Foureau, Reynaud-Gaubert, Roux, Demant, Le Pavec, Kessler, Mornex, Messika, Falque, Le Borgne, Boussaud, Tissot, Hombourger, Bressollette-Bodin and Charreau.)

Objective: Immunocompromised patients have an increased risk of a severe form of COVID-19. The clinical efficacy of the tixagevimab/cilgavimab monoclonal antibody combination as pre-exposure prophylaxis against BA.1 and BA.2 SARS-CoV-2 Omicron sublineages is unknown. We aimed to describe the incidence and outcomes of COVID-19 among immunocompromised patients receiving tixagevimab/cilgavimab as preexposure prophylaxis during the Omicron wave in France., Methods: This was an observational multicentre cohort study of immunocompromised patients receiving tixagevimab/cilgavimab as preexposure prophylaxis between December 28, 2021 and March 31, 2022. Patients received tixagevimab/cilgavimab 150/150 mg intramuscularly if they had impaired vaccine response and a high risk of severe form of COVID-19., Results: Tixagevimab/cilgavimab was administered to 1112 immunocompromised patients. After a median (range) follow-up of 63 (49-73) days, COVID-19 was confirmed in 49/1112 (4.4%) ≥5 days after treatment. During the study period, mean weekly incidence rate was 1669 in 100 000 inhabitants in Ile-de-France and 530 in 100 000 among patients who received tixagevimab/cilgavimab prophylaxis. Among infected patients, 43/49 (88%) had a mild-to-moderate form and 6/49 (12%) had a moderate-to-severe form of COVID-19. Patients with moderate-to-severe illnesses were less likely to have received early therapies than patients with mild forms (53.5% vs. 16.7% respectively) and 2/49 (4%) patients died from COVID-19., Discussion: Our study reported a low rate of infections and severe illnesses among immunocompromised patients treated with tixagevimab/cilgavimab. A global preventive strategy including vaccines, preexposure prophylaxis with monoclonal antibodies, and early therapies might be effective to prevent severe forms of COVID-19 among severely immunocompromised patients., (Copyright © 2022 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)