Successful lung transplantation in genetic methionyl-tRNA synthetase-related alveolar proteinosis/lung fibrosis without recurrence under methionine supplementation: Medium-term outcome in 4 cases.

Pulmonary alveolar proteinosis (PAP) results from the accumulation of lipoproteinaceous material in the alveoli and alveolar macrophages, and can be associated with pulmonary fibrosis, with a need for lung transplantation (LTx). Causes of PAP are autoimmune (90%-95%), secondary (5%), or hereditary (<1%). Patients with hereditary PAP are generally not considered for isolated LTx, due to the high probability of recurrence after LTx, and only a challenging scenario with sequential LTx followed by hematopoietic stem cell transplantation (HSCT) was reported as successful. Recently, a new genetic cause of PAP linked to mutations in the methionyl-tRNA synthetase (MARS) gene has been reported, with a highly variable clinical presentation. Because clinical correction of the defective MARS activity with methionine supplementation has been reported in nontransplanted children, we reassessed the feasibility of LTx for candidates with MARS-related PAP/fibrosis. We report 3 cases of LTx performed for MARS-related pulmonary alveolar proteinosis-pulmonary fibrosis without recurrence under methionine supplementation, whereas another fourth case transplanted without supplementation had fatal PAP recurrence. These results suggest the effectiveness of methionine in correcting defective MARS activity and also looking for this very rare diagnosis in case of unclassified PAP/fibrosis. It argues for not excluding the feasibility of isolated LTx in patients with MARS mutation.

Results of Lung Transplantation for Cystic Fibrosis With Selected Donors Over 65 Years Old.

Lung transplantation is limited by the shortage of suitable donors. Many programs have begun to use extended criteria donors. Donors over 65 years old are rarely reported, especially for young cystic fibrosis recipients. This monocentric study was conducted for cystic fibrosis recipients from January 2005 to December 2019, comparing two cohorts according to lung donor age (<65 years or ≥65 years). The primary objective was to assess the survival rate at 3 years using a Cox multivariable model. Of the 356 lung recipients, 326 had donors under 65 years, and 30 had donors over 65 years. Donors' characteristics did not differ significantly in terms of sex, time on mechanical ventilation before retrieval, and partial pressure of arterial oxygen/fraction of inspired oxygen ratio. There were no significant differences in post-operative mechanical ventilation duration and incidence of grade 3 primary graft dysfunction between the two groups. At 1, 3, and 5 years, the percentage of predicted forced expiratory volume in 1 s (p = 0.767) and survival rate did not differ between groups (p = 0.924). The use of lungs from donors over 65 years for cystic fibrosis recipients allows extension of the donor pool without compromising results. Longer follow-up is needed to assess the long-term effects of this practice.

Systems prediction of chronic lung allograft dysfunction: Results and perspectives from the Cohort of Lung Transplantation and Systems prediction of Chronic Lung Allograft Dysfunction cohorts.

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.

Inverted direct allorecognition triggers early donor-specific antibody responses after transplantation.

The generation of antibodies against donor-specific major histocompatibility complex (MHC) antigens, a type of donor-specific antibodies (DSAs), after transplantation requires that recipient's allospecific B cells receive help from T cells. The current dogma holds that this help is exclusively provided by the recipient's CD4+ T cells that recognize complexes of recipient's MHC II molecules and peptides derived from donor-specific MHC alloantigens, a process called indirect allorecognition. Here, we demonstrated that, after allogeneic heart transplantation, CD3ε knockout recipient mice lacking T cells generate a rapid, transient wave of switched alloantibodies, predominantly directed against MHC I molecules. This is due to the presence of donor CD4+ T cells within the graft that recognize intact recipient's MHC II molecules expressed by B cell receptor-activated allospecific B cells. Indirect evidence suggests that this inverted direct pathway is also operant in patients after transplantation. Resident memory donor CD4+ T cells were observed in perfusion liquids of human renal and lung grafts and acquired B cell helper functions upon in vitro stimulation. Furthermore, T follicular helper cells, specialized in helping B cells, were abundant in mucosa-associated lymphoid tissue of lung and intestinal grafts. In the latter, more graft-derived passenger T cells correlated with the detection of donor T cells in recipient's circulation; this, in turn, was associated with an early transient anti-MHC I DSA response and worse transplantation outcomes. We conclude that this inverted direct allorecognition is a possible explanation for the early transient anti-MHC DSA responses frequently observed after lung or intestinal transplantations.

Blood Lactate During Double-Lung Transplantation: A Predictor of Grade-3 Primary Graft Dysfunction.

OBJECTIVE: Many prognostic factors of grade-3 primary graft dysfunction at postoperative day 3 (PGD3-T72) have been reported, but intraoperative blood lactate level has not been studied. The present retrospective study was done to test the hypothesis that intraoperative blood lactate level (BLL) could be a predictor of PGD3-T72 after double-lung transplantation. DESIGN: Retrospective monocentric cohort study. SETTING: Foch University Hospital, Suresnes, France. PARTICIPANTS: Patients having received a double-lung transplantation between 2012 and 2019. Patients transplanted twice during the study period, having undergone a multiorgan transplantation, or cardiopulmonary bypass, and those under preoperative extracorporeal membrane oxygenation, were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Analysis was performed on a cohort of 449 patients. Seventy-two (16%) patients had a PGD3-T72. Blood lactate level increased throughout surgery to reach a median value of 2.2 (1.6-3.2) mmol/L in the No-PGD3-T72 group and 3.4 (2.3-5.0) mmol/L in the PGD3-T72 group after second lung implantation. The best predictive model for PGD3-T72 was obtained adding a lactate threshold of 2.6 mmol/L at the end of surgery to the clinical model, and the area under the curve was 0.867, with a sensitivity = 76.9% and specificity = 85.4%. Repeated-measures mixed model of BLL during surgery remained significant after adjustment for covariates (F ratio= 4.22, p < 0.001 for interaction). CONCLUSIONS: Blood lactate level increases during surgery and reaches a maximum after the second lung implantation. A value below the threshold of 2.6 mmol/L at the end of surgery has a high negative predictive value for the occurrence of a grade-3 primary graft dysfunction at postoperative day 3.

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. CD24hi CD38hi 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 CD24hi CD38hi 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 CD24hi CD38hi 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.

C4d detection and histological patterns in the diagnosis of antibody-mediated rejection after lung transplantation: a single-centre study.

AIMS: Antibody-mediated rejection (AMR) is an emerging and challenging issue in transplantation. Endothelial deposition of C4d and microvascular inflammation (MI) are reliable markers of AMR in renal and cardiac transplantation, but remain controversial in the lung. Our aim was to assess C4d immunohistochemistry and histological patterns for the diagnosis of lung AMR. METHODS AND RESULTS: We reviewed 158 transbronchial biopsies (TBBs) (n = 85 clinically indicated, and n = 73 surveillance TBBs) from 48 recipients, blinded to clinical and serological data. C4d was scored as 0, 1+ (<10%), 2+ (10-50%) or 3+ (>50%). TBBs were reassessed for MI and acute lung injury (ALI). Donor-specific antibodies (DSAs), acute clinical graft dysfunction and chronic lung allograft graft dysfunction (CLAD) were recorded. C4d3+, C4d2+, C4d1+ and C4d0 occurred respectively in four (2.5%), six (3.8%), 28 (17.7%) and 120 (75.9%) TBBs. MI and ALI were rare but more frequent in C4d1-3+ TBBs than in the absence of C4d. C4d2+ was frequently observed with concomitant infection. Among the surveillance TBBs, only two (2.7%) showed MI. Neither ALI nor C4d3+ was diagnosed on surveillance TBBs. No significant association was found between histopathological findings and DSAs. All four patients with C4d3+ could retrospectively be diagnosed with AMR and developed CLAD. CONCLUSION: Although rare, diffuse C4d deposition appears to be a strong indication of acute clinical AMR in lung transplant patients, whereas intermediate C4d2+ requires more investigations. In stable patients, histopathology and C4d may lack the sensitivity to diagnose subclinical AMR. This emphasises the need for a multidisciplinary evaluation of each suspected AMR case, and the need for complementary diagnostic tools.

Prevalence of respiratory viruses among adults, by season, age, respiratory tract region and type of medical unit in Paris, France, from 2011 to 2016.

BACKGROUND: Multiplex PCR tests have improved our understanding of respiratory viruses' epidemiology by allowing their wide range detection. We describe here the burden of these viruses in hospital settings over a five-year period. METHODS: All respiratory samples from adult patients (>20 years old) tested by multiplex-PCR at the request of physicians, from May 1 2011 to April 30 2016, were included retrospectively. Viral findings are reported by season, patient age group, respiratory tract region (upper or lower) and type of clinical unit (intensive care unit, pneumology unit, lung transplantation unit and other medical units). RESULTS: In total, 7196 samples (4958 patients) were included; 29.2% tested positive, with viral co-infections detected in 1.6% of samples. Overall, two viral groups accounted for 60.2% of all viruses identified: picornaviruses (rhinovirus or enterovirus, 34.3%) and influenza (26.6%). Influenza viruses constituted the group most frequently identified in winter (34.4%), in the upper respiratory tract (32%) and in patients over the age of 70 years (36.4%). Picornavirus was the second most frequently identified viral group in these populations and in all other groups, including lower respiratory tract infections (41.3%) or patients in intensive care units (37.6%). CONCLUSION: This study, the largest to date in Europe, provides a broad picture of the distribution of viruses over seasons, age groups, types of clinical unit and respiratory tract regions in the hospital setting. It highlights the burden associated with the neglected picornavirus group. These data have important implications for the future development of vaccines and antiviral drugs.

Inhibition of T Cell Alloreactivity by Bronchial Epithelium Is Impaired in Lung Transplant Recipients, Through Pathways Involving TGF-ß, IL-10 and HLA-G.

BACKGROUND: Bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx) results from bronchial epithelial cell (BECs) damages, thought to be orchestrated by T cells primed by antigen-presenting cell presenting alloantigens. In this cell cross-talk, BECs are also suspected to play a pivotal immunosuppressive role in T cell alloreactivity. We studied the immunomodulating role of BECs in a human ex vivo model of allogeneic T cell response, both in healthy subjects and LTx recipients. METHODS: BECs from 35 LTx recipients (n = 22 stable, n = 13 BOS) and healthy controls (n = 25) were cultured as primary cell cultures. Their inhibitory capacities through the involvement of tolerogenic molecules (HLA-G, TGF-ß, and IL-10) were tested on a mixed lymphocyte reaction between antigen-presenting cells and recipient T cells. RESULTS: Control BECs inhibited T cell alloproliferation by a mean of 53 ± 7%. This inhibitory effect of BECs was significantly reduced in the stable LTx group (24 ± 8%, P = 0.009), but not in the BOS TxP group (53 ± 10%, P = 0.97). Neutralization of HLA-G, TGF-ß, and IL-10 partially restored T cell alloproliferation, arguing for their involvement in the immunosuppressive effect of BECs. BECs culture supernatant from stable LTx patients with impaired BEC properties showed a skewed Th2-type secretion profile (high IL-4/IFN-γ ratio). CONCLUSIONS: The inhibitory properties of BECs are dysregulated in stable LTx recipients, which could suggest their instrumental role in the initiation of BOS process and potential targeted therapies.

Blood Gene Expression Predicts Bronchiolitis Obliterans Syndrome.

Bronchiolitis obliterans syndrome (BOS), the main manifestation of chronic lung allograft dysfunction, leads to poor long-term survival after lung transplantation. Identifying predictors of BOS is essential to prevent the progression of dysfunction before irreversible damage occurs. By using a large set of 107 samples from lung recipients, we performed microarray gene expression profiling of whole blood to identify early biomarkers of BOS, including samples from 49 patients with stable function for at least 3 years, 32 samples collected at least 6 months before BOS diagnosis (prediction group), and 26 samples at or after BOS diagnosis (diagnosis group). An independent set from 25 lung recipients was used for validation by quantitative PCR (13 stables, 11 in the prediction group, and 8 in the diagnosis group). We identified 50 transcripts differentially expressed between stable and BOS recipients. Three genes, namely POU class 2 associating factor 1 (POU2AF1), T-cell leukemia/lymphoma protein 1A (TCL1A), and B cell lymphocyte kinase, were validated as predictive biomarkers of BOS more than 6 months before diagnosis, with areas under the curve of 0.83, 0.77, and 0.78 respectively. These genes allow stratification based on BOS risk (log-rank test p < 0.01) and are not associated with time posttransplantation. This is the first published large-scale gene expression analysis of blood after lung transplantation. The three-gene blood signature could provide clinicians with new tools to improve follow-up and adapt treatment of patients likely to develop BOS.

Systematic analysis of blood cell transcriptome in end-stage chronic respiratory diseases.

BACKGROUND: End-stage chronic respiratory diseases (CRD) have systemic consequences, such as weight loss and susceptibility to infection. However the mechanisms of such dysfunctions are as yet poorly explained. We hypothesized that the genes putatively involved in these mechanisms would emerge from a systematic analysis of blood mRNA profiles from pre-transplant patients with cystic fibrosis (CF), pulmonary hypertension (PAH), and chronic obstructive pulmonary disease (COPD). METHODS: Whole blood was first collected from 13 patients with PAH, 23 patients with CF, and 28 Healthy Controls (HC). Microarray results were validated by quantitative PCR on a second and independent group (7PAH, 9CF, and 11HC). Twelve pre-transplant COPD patients were added to validate the common signature shared by patients with CRD for all causes. To further clarify a role for hypoxia in the candidate gene dysregulation, peripheral blood mononuclear cells from HC were analysed for their mRNA profile under hypoxia. RESULTS: Unsupervised hierarchical clustering allowed the identification of 3 gene signatures related to CRD. One was common to CF and PAH, another specific to CF, and the final one was specific to PAH. With the common signature, we validated T-Cell Factor 7 (TCF-7) and Interleukin 7 Receptor (IL-7R), two genes related to T lymphocyte activation, as being under-expressed. We showed a strong impact of the hypoxia on modulation of TCF-7 and IL-7R expression in PBMCs from HC under hypoxia or PBMCs from CRD. In addition, we identified and validated genes upregulated in PAH or CF, including Lectin Galactoside-binding Soluble 3 and Toll Like Receptor 4, respectively. CONCLUSIONS: Systematic analysis of blood cell transcriptome in CRD patients identified common and specific signatures relevant to the systemic pathologies. TCF-7 and IL-7R were downregulated whatever the cause of CRD and this could play a role in the higher susceptibility to infection of these patients.

Neural mechanisms underlying breathing complexity.

Breathing is maintained and controlled by a network of automatic neurons in the brainstem that generate respiratory rhythm and receive regulatory inputs. Breathing complexity therefore arises from respiratory central pattern generators modulated by peripheral and supra-spinal inputs. Very little is known on the brainstem neural substrates underlying breathing complexity in humans. We used both experimental and theoretical approaches to decipher these mechanisms in healthy humans and patients with chronic obstructive pulmonary disease (COPD). COPD is the most frequent chronic lung disease in the general population mainly due to tobacco smoke. In patients, airflow obstruction associated with hyperinflation and respiratory muscles weakness are key factors contributing to load-capacity imbalance and hence increased respiratory drive. Unexpectedly, we found that the patients breathed with a higher level of complexity during inspiration and expiration than controls. Using functional magnetic resonance imaging (fMRI), we scanned the brain of the participants to analyze the activity of two small regions involved in respiratory rhythmogenesis, the rostral ventro-lateral (VL) medulla (pre-Bötzinger complex) and the caudal VL pons (parafacial group). fMRI revealed in controls higher activity of the VL medulla suggesting active inspiration, while in patients higher activity of the VL pons suggesting active expiration. COPD patients reactivate the parafacial to sustain ventilation. These findings may be involved in the onset of respiratory failure when the neural network becomes overwhelmed by respiratory overload We show that central neural activity correlates with airflow complexity in healthy subjects and COPD patients, at rest and during inspiratory loading. We finally used a theoretical approach of respiratory rhythmogenesis that reproduces the kernel activity of neurons involved in the automatic breathing. The model reveals how a chaotic activity in neurons can contribute to chaos in airflow and reproduces key experimental fMRI findings.

Survival benefit of lung transplant for cystic fibrosis since lung allocation score implementation.

RATIONALE: The survival benefit of lung transplantation (LT) in adult patients with cystic fibrosis (CF) is debated. OBJECTIVES: We sought to assess the survival benefit of LT in adult patients with CF. METHODS: We used data from the United Network for Organ Sharing Registry to identify adult patients with CF on a wait list for LT in the United States between 2005 and 2009. Survival times while on the wait list and after LT were modeled by use of a Cox model that incorporated transplantation status as a time-dependent covariate. Evolution in lung allocation score (LAS) while on the wait list was used as a surrogate for disease severity. We fitted a model for the joint distribution of survival and longitudinal disease process (LAS over time). MEASUREMENTS AND MAIN RESULTS: A total of 704 adult patients with CF were registered on a wait list during the study period. The cumulative incidence of LT was 39.3% (95% confidence interval, 35.6-42.9%) at 3 months and 64.7% (61.0-68.4%) at 12 months, whereas the incidence of death while on the wait list at the same times was 8.5% (6.4-10.6%) and 12.9% (10.3-15.5%), respectively. Survival after LT was 96.5% (94.7-98.2%) at 3 months; 88.4% (85.1-91.8%) at 12 months; and 67.8% (59.9-76.8%) at 3 years. LT conferred a 69% reduction in the instantaneous risk of death (51-80%). The interaction between LAS and LT was significant: the higher the LAS, the greater the survival benefit of LT (P < 0.001). CONCLUSIONS: LT confers a survival benefit for adult patients with CF.

Thrombotic microangiopathy with acquired deficiency in ADAMTS 13 activity in lung transplant recipients.

BACKGROUND: Thrombotic microangiopathy may develop after solid organ transplantation, but it is usually not associated with severe deficiency in von Willebrand factor-cleaving metalloprotease (ADAMTS 13) activity. METHODS: We present the cases of two lung transplant recipients who experienced a thrombotic microangiopathy associated with an acquired severe (<5%) deficiency in ADAMTS 13 activity. RESULTS: A major feature of both cases was the occurrence of a diffuse alveolar hemorrhage. CONCLUSION: Our two cases of lung transplant patients, with thrombotic microangiopathy related to an acquired ADAMTS 13 deficiency recipients, confirm that this mechanism may also be involved in the pathogenesis of thrombotic microangiopathy developing after solid organ transplantation. Therefore, we consider that ADAMTS 13 activity should be assessed on a systematic basis in this setting.

Lung transplantation for pulmonary langerhans' cell histiocytosis: a multicenter analysis.

BACKGROUND: Lung transplantation (LT) may represent a therapeutic option in case of advanced pulmonary Langerhans' cell histiocytosis (PLCH). Little is known however about the characteristics of the patients considered for LT or its results. METHODS: We conducted a retrospective multicenter study by questionnaire on 39 patients who underwent LT for end-stage PLCH at seven centers in France. RESULTS: Of the 39 patients, 15 received single lung transplantation, 15 double lung transplantation and 9 heart-lung transplantation. At evaluation, extrapulmonary involvement was present in 31% of the patients, pulmonary hypertension (PAPm>25 mm Hg) was observed in 92% of cases and was moderate-to-severe (PAPm> or =35 mm Hg) in 72.5%. The survival was 76.9% at 1 year, 63.6% at 2 years, 57.2% at 5 years, and 53.7% at 10 years. Recurrence of the disease occurred in eight cases (20.5%) with no impact on the survival rate. The sole risk factor for recurrence of the disease was the presence of preoperative extrapulmonary involvement. CONCLUSION: Severe pulmonary hypertension is a common feature in patients with end-stage PLCH. Given the good postransplant survival rate and despite a recurrence rate of the disease of approximately 20% after LT, we conclude that LT is a therapeutic option in this setting.

Functional results of unilateral lung volume reduction surgery in alpha1-antitrypsin deficient patients.

Lung volume reduction surgery (LVRS) has been shown to improve lung function and exercise tolerance in patients with severe emphysema. Some predictors of poor outcome have been described but the role of alpha1-antitrypsin (alpha1-AT) deficiency is still not well known. The aim of this study was to analyze the results of unilateral LVRS in our center according to the alpha1-AT status. The results of LVRS in 17 deficient patients and 35 nondeficient patients were analyzed at 3-6 months and 1 year after surgery. Compared with baseline, a significant improvement of FEV1, partial pressure in arterial blood (PaO2), dyspnea score and walking distance was observed in the two groups at 3-6 months after surgery and the studied parameters remained significantly improved at 1 year in the nondeficient group. By contrast, PaO2 and walking distance returned towards baseline in the deficient group at 1 year whereas improvement of FEV1 and dyspnea score was persistent. Mean values of FEV, at baseline, 3-6 months, and 1 year were 22 +/- 6%, 29 +/- 11%, and 26 +/- 9% and 28 +/- 12%, 38 +/- 17%, and 40 +/- 17% predicted in the deficient group and in the non-deficient group, respectively. In conclusion, the functional benefit is short-lasting in alpha1-AT deficient patients after unilateral LVRS.