Subcutaneous fixation model for complex stenting of recurrent laryngotracheal stenosis.

BACKGROUND: A straight silicone stent can be used to treat proximal benign tracheal stenosis in non-surgical candidates. However, stent migration is a common complication when placed at a particular location and can lead to major complications. This case series of laryngotracheal stenosis reports a fixation method for straight silicone stents in the subglottic trachea (Stage 3 of the McCaffrey classification). METHODS: The medical charts of these patients scheduled for straight silicone stent placement with suture fixation between 2014 and 2020 at the CHU UCL Namur Hospital (Belgium) were retrospectively reviewed. The procedure was performed using a rigid bronchoscope. Details of the procedure were obtained from medical records. RESULTS: This case series included six patients (males: 4, females: 2). The median patient age was 59 years. Two suture fixations were placed following previous silicone stent migration episodes, whereas the others were placed proactively to avoid this risk. All fixations were performed by the device Freka® Pexact II ENFIt®, originally developed for gastropexy in endoscopic gastrostomy. The sutures were subcutaneously buried. CONCLUSIONS: During the 6-month follow-up period, complications such as fixation issues and stent migration were reported despite the off-label use of the treatment. The straight silicone stent fixation technique used in this case series was simple and effective for securing the stent in upper benign tracheal stenosis.

Systemic Inflammation/Nutritional Status Scores Are Prognostic but Not Predictive in Metastatic Non-Small-Cell Lung Cancer Treated with First-Line Immune Checkpoint Inhibitors.

Biomarkers of systemic inflammation/nutritional status have been associated with outcomes in advanced-stage non-small-cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs). However, most of them were not tested in cohorts of patients treated with ICIs in combination with chemotherapy (CT) (ICI + CT) or with CT alone, making it impossible to discriminate a predictive from a prognostic effect. We conducted a single-center retrospective study to search for associations between various baseline biomarkers/scores that reflected the systemic inflammation/nutritional status (Lung Immune Prognostic Index, Modified Lung Immune Prognostic Index, Scottish Inflammatory Prognostic Score, Advanced Lung Cancer Inflammation Index, EPSILoN, Prognostic Nutritional Index, Systemic Immune-Inflammation Index, Gustave Roussy Immune Score, Royal Marsden Hospital Prognostic Score, Lung Immuno-oncology Prognostic Score 3, Lung Immuno-oncology Prognostic Score 4, score published by Holtzman et al., and Glasgow Prognostic Score) and outcomes in metastatic NSCLC treated in a first-line setting either with ICI in monotherapy (cohort 1; n = 75), ICI + CT (cohort 2; n = 56), or CT alone (cohort 3; n = 221). In the three cohorts, the biomarkers/scores were moderately associated with overall survival (OS) and progression-free survival (PFS). Their prognostic performance was relatively poor, with a maximum c-index of 0.66. None of them was specific to ICIs and could help to choose the best treatment modality. The systemic inflammation/nutritional status, associated with outcomes independently of the treatment, is therefore prognostic but not predictive in metastatic NSCLC.

The genomic landscape of nonsmall cell lung carcinoma in never smokers.

Lung cancer is the number one cause of cancer-related death worldwide with cigarette smoking as its major risk factor. Although the incidence of lung cancer in never smokers is rising, this subgroup of patients is underrepresented in genomic studies of lung cancer. Here, we assembled a prospective cohort of 46 never-smoking, nonsmall cell lung cancer (NSCLC) patients and performed whole-exome and low-coverage whole-genome sequencing on tumors and matched germline DNA. We observed fewer somatic mutations, genomic breakpoints and a smaller fraction of the genome with chromosomal instability in lung tumors from never smokers compared to smokers. The lower number of mutations, enabled us to identify TSC22D1 as a potential driver gene in NSCLC. On the other hand, the frequency of mutations in actionable genes such as EGFR and ERBB2 and of amplifications in MET were higher, while the mutation rate of TP53, which is a negative prognostic factor, was lower in never smokers compared to smokers. Together, these observations suggest a more favorable prognosis for never smokers with NSCLC. Classification of somatic mutations into six-substitution type patterns or into 96-substitution type signatures revealed distinct clusters between smokers and never smokers. Particularly, we identified in never smokers signatures related to aging, homologous recombination damage and APOBEC/AID activity as the most important underlying processes of NSCLC. This further indicates that second-hand smoking is not driving NSCLC pathogenesis in never smokers.

Increased IgA Expression in Lung Lymphoid Follicles in Severe Chronic Obstructive Pulmonary Disease.

RATIONALE: Accumulation of B cells and lymphoid follicles (LFs) has been described in chronic obstructive pulmonary disease (COPD) airways, but the functional status of lung B cells remains poorly known. OBJECTIVES: To characterize LFs for expression of IgA, the main mucosal antibody. METHODS: The presence of B cells and LFs, including intrafollicular IgA expression, were determined in the lung from patients with COPD (n = 37) versus control subjects (n = 34) by immunohistochemistry. We also evaluated follicular IgA responses in the lungs from mice infected with Pseudomonas aeruginosa (PAO1) (n = 10 per group) and in smoking mice. MEASUREMENTS AND MAIN RESULTS: Whereas in smokers B-cell numbers slightly increased, robust increases in B-cell and LF numbers (mainly in distal airways) were only observed in severe COPD. Most follicular B cells were IgM+ (70-80%), but IgA+ (and not IgG+) B-cell numbers were increased in LFs from severe COPD compared with control subjects (twofold, 44.7% vs. 25.2%), and this was significant in distal but not proximal airways. Follicular IgA response was also observed in PAO1-infected mouse lungs, but not after smoke exposure. Moreover, follicular IgA expression associated with expression of IL-21, which was very potent to activate immunoglobulin production in vitro. CONCLUSIONS: This study shows that IgA production occurs in peribronchiolar LFs from severe COPD, where IL-21-producing T cells are present, and presumably represents a feature of exacerbated mucosal adaptive immune responses against microbial and/or self-antigens.

Long term outcome after 48 Gy stereotactic ablative body radiotherapy for peripheral stage I non-small cell lung cancer.

BACKGROUND: To evaluate the outcome of patients treated with stereotactic ablative body radiotherapy (SABR) with curative intent for stage I non-small cell lung cancer (NSCLC) with regard to local, regional and distant tumor control, disease-free survival (DFS), overall survival (OS) and toxicity. METHODS: Data of 300 patients treated with SABR for NSCLC cancer for the period of November 2007 to June 2016 were retrospectively analyzed. Of which, 189 patients had single primary lung lesion and were included in the study. The prescribed dose for the tumor was 48 Gy, given in 12 Gy × 4 fractions for all patients. In 2010, an improved protocol was established in advanced technology for the planning CT, dose calculation and imaging. Cumulative incidence function (CIF) of local, regional, distant or any recurrences were computed using competing risk analysis with death as a competing event. Survivals (DFS and OS) were estimated using the Kaplan-Meier method and Cox proportional regression was used for comparisons. Toxicities were graded according to the common terminology criteria for adverse events version 4.0 (CTCAE v.4). RESULTS: Diagnosis was histologically confirmed in 42% of the patients (N = 80). At 1, 2 and 4 years, the cumulative incidence function (CIF) of local relapses were 8% [4-13%], 15% [10-21%] and 18% [12-25%], the CIF of regional relapses were 4% [2-8%], 10% [6-16%] and 12% [8-19%], the CIF of distant relapses were 9% [5-14%], 15% [11-22%] and 20% [15-28%] and the CIF of any relapses were 14% [10-20%], 28% [22-36%], 34% [27-43%], respectively. After 1, 2 and 4 years, the OS rates were 83% [95% CI: 78-89%] (N = 128), 65% [95% CI: 57-73%] (N = 78) and 37% [95% CI: 29-47%] (N = 53), respectively. The median survival time was 37 months. The DFS after 1, 2 and 4 years reached 75% [95% CI: 68-81%] (N = 114), 49% [95% CI: 42-58%] (N = 60) and 31% [95% CI: 24-41%] (N = 41), respectively. No grade 4 or 5 toxicity was observed. CONCLUSIONS: We observed a long-term local control and survival after SABR for peripheral stage I NSCLC in this large series of patients with the expected low toxicity.

Diagnostic Accuracy and Safety of CT-Guided Percutaneous Transthoracic Needle Biopsies: 14-Gauge versus 22-Gauge Needles.

PURPOSE: To compare the diagnostic accuracy and safety of a 14-gauge core needle versus a 22-gauge fine needle in the evaluation of thoracic lesions by CT-guided percutaneous transthoracic needle biopsy (TTNB). MATERIALS AND METHODS: Medical charts of all patients who underwent CT-guided percutaneous transthoracic core-needle biopsies (CNBs) with a 14-gauge Spirotome device (99 patients, 102 procedures) and fine-needle biopsies (FNBs) with a 22-gauge Rotex needle (92 patients, 102 procedures) between 2007 and 2013 at a single academic institution were retrospectively reviewed. Variables that could influence diagnostic accuracy and safety were collected. RESULTS: The overall and cancer-specific diagnostic accuracy rates were 90% and 94%, respectively, with CNB, versus 82% and 89% with FNB. Precise cancer type/subtype was provided by 97% of CNBs versus 65% of FNBs (P < .001). In patients with lung cancer considered for targeted therapy, biomarker analyses were feasible in 80% of CNBs versus 0% of FNBs (P < .001). The rate of pneumothorax was significantly higher with CNB versus FNB (31% vs 19%; P = .004), but chest tube insertion rates were similar (10% vs 11%, respectively). Major bleeding complications occurred in 1% of CNBs versus 2% of FNBs and were associated with one death in the CNB group. CONCLUSIONS: Percutaneous transthoracic CNB with a 14-gauge Spirotome needle provided better characterization of cancer lesions and allowed biomarker analyses without a significant increase in major procedural complications.

Systematic qualitative review of randomised trials conducted in nonsmall cell lung cancer with a noninferiority or equivalence design.

The use of noninferiority randomised trials for patients with advanced non-small cell lung cancer has emerged during the past 10-15 years but has raised some issues related to their justification and methodology. The present systematic review aimed to assess trial characteristics and methodological aspects. All randomised clinical trials with a hypothesis of noninferiority/equivalence, published in English, were identified. Several readers extracted a priori defined methodological information. A qualitative analysis was then performed. We identified 20 randomised clinical trials (three phase II and 17 phase III), 11 of them being conducted in strong collaboration with industry. We highlighted some deficiencies in the reports like the lack of justification for both the noninferiority assumption and the definition of the noninferiority margin, as well as inconsistencies between the results and the authors' conclusions. CONSORT guidelines were better followed for general items than for specific items (p<0.001). Improvement in the reporting of the meth"odology of noninferiority/equivalence trials is needed to avoid misleading interpretation and to allow readers to be fully aware of the assumptions underlying the trial designs. They should be restricted to limited specific situations with a strong justification why a noninferiority hypothesis is acceptable.

Improved Accuracy and Sensitivity in Diagnosis and Staging of Lung Cancer with Systematic and Combined Endobronchial and Endoscopic Ultrasound (EBUS-EUS): Experience from a Tertiary Center.

BACKGROUND: Combined endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and endoscopic ultrasound-guided tissue acquisition (EUS-TA) are accurate procedures for the diagnosis and staging of mediastinal lymph nodes (MLNs) in lung cancer. However, the respective contribution of separate and combined procedures in diagnosis and staging has not been fully studied. The aim of this study was to assess their respective performances. METHODS: Patients with suspected malignant MLNs in lung cancer or recurrence identified by PET-CT who underwent combined EBUS-TBNA and EUS-TA were retrospectively reviewed. RESULTS: A total of 141 patients underwent both procedures. Correct diagnosis was obtained in 82% with EBUS-TBNA, 91% with EUS-TA, and 94% with the combined procedure. The overall sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of EBUS-TBNA, EUS-TA, and the combined procedure for diagnosing malignancy were [75%, 100%, 100%, 58%], [87%, 100%, 100%, 75%], and [93%, 100%, 100%, 80%], respectively, with a significantly better sensitivity of the combined procedure (p < 0.0001). Staging (82/141 patients) was correctly assessed in 74% with EBUS-TBNA, 68% with EUS-TA, and 85% with the combined procedure. The overall sensitivity, specificity, PPV, and NPV of EBUS-TBNA, EUS-TA, and the combined procedure for lung cancer staging were [62%, 100%, 100%, 55%], [54%, 100%, 100%, 50%], and [79%, 100%, 100%, 68%], respectively, significantly better in terms of sensitivity for the combined procedure (p < 0.001). CONCLUSION: The combined EBUS-EUS approach in lung cancer patients showed better accuracy and sensitivity in diagnosis and staging when compared with EBUS-TBNA and EUS-TA alone.

Long-term complete remission after severe pembrolizumab-induced immune-related encephalitis in metastatic lung adeno-squamous carcinoma: A case report.

Immune checkpoint inhibitors became the treatment of choice, in monotherapy or in association with platinum-based doublet chemotherapy, in first-line therapy for advanced-stage non-small-cell lung cancer without oncogenic driver. Nevertheless, it can be associated with diverse immune-related adverse events; several immune-related adverse events can also follow each other involving multiple organ systems, leading to immune checkpoint inhibitors discontinuation and immunosuppressive therapy that could compromise the prognosis of patients, with the exception of rare situations such as this clinical case. This case report illustrates a succession of immune-related adverse events including a rare and severe pembrolizumab-induced immune-related encephalitis in a patient with metastatic lung adeno-squamous carcinoma in whom we could observe a long-term and complete remission despite discontinuation of treatment and high-dose corticosteroids. In metastatic non-small-cell lung cancer, a disease with a poor initial prognosis, some patients can benefit from immune checkpoint inhibitors and can even now present a long-term and complete remission and this despite severe and rare immune-related adverse events, high-dose corticosteroids and an early discontinuation of treatment.

Treatment and Prognosis of Patients with Lung Cancer and Combined Interstitial Lung Disease.

BACKGROUND: Interstitial lung disease (ILD) is associated with a higher lung cancer (LC) risk and may impact cancer's clinical characteristics, treatment strategies, and outcomes. This impact's extent is unclear, particularly in Caucasians. METHODS: In this retrospective observational study, we reviewed the files of all LC patients diagnosed in a 38-month period. Expert radiologists reviewed the computed tomography scans performed at diagnosis. Patients with LC and ILD (n = 29, 7%) were compared to those without ILD (n = 363, 93%) for population and cancer characteristics, treatments, and clinical outcomes. RESULTS: Patients with LC and ILD were older (73 ± 8 vs. 65 ± 11 years; p < 0.001). There was no significant difference in LC histology, localization, stage, or treatment modalities. The respiratory complication rate after cancer treatment was significantly higher in the ILD group (39% vs. 6%; p < 0.01). Overall survival rates were similar at 12 (52% vs. 59%; p = 0.48) and 24 months (41% vs. 45%; p = 0.64) but poorer in the ILD group at 36 months, although not statistically significant (9% vs. 39%; p = 0.06). The ILD group had a higher probability of death (hazard ratio (HR) = 1.49 [0.96;2.27]), but this was not statistically significant (p = 0.06). In a Cox regression model, patients with ILD treated surgically had a significantly higher mortality risk (HR = 2.37 [1.1;5.09]; p = 0.03). CONCLUSIONS: Patients with combined LC and ILD have worse clinical outcomes even when similar treatment modalities are offered.

Restin protein expression in non-small cell lung cancer.

BACKGROUND: Restin is a member of the melanoma-associated antigen (MAGE) superfamily. Its expression has been reported to be up- or downregulated in cancer. Preclinical data suggest it is a tumor suppressor. In this study, we aimed to evaluate restin expression and prognostic value in non-small cell lung cancer (NSCLC). METHODS: Restin expression was analyzed by immunohistochemistry in three tissue microarrays consisting of formalin-fixed/paraffin-embedded NSCLC specimens from 113 patients, represented in triplicate. Restin staining H-score was the result of the staining intensity (0-no, 1-weak, 2-moderate, and 3-strong) multiplied by the percentage of stained tumor cells; it was defined as low if 1-100, moderate if 101-200, and strong if 201-300. Haverage-score was the average H-score in the triplicate. Restin Haverage-scores were tested for correlations with clinical and pathological characteristics and patient outcome. RESULTS: Restin expression was localized to the cytoplasm, with nuclear enhancement, of 112/113 (99.1%) NSCLCs. Restin Haverage-scores were 0 in 1/113 (0.88%), low in 15/113 (13.3%), moderate in 48/113 (42.5%), and strong in 49/113 (43.4%) NSCLCs. Restin Haverage-scores did not correlate with NSCLC histological subtype, disease stage, recurrence/progression-free, or overall survival. CONCLUSION: Restin is moderately to strongly expressed in the majority of NSCLC tumors but its expression has no prognostic value in patients with NSCLC.

Expression of focal adhesion kinase in small-cell lung carcinoma.

BACKGROUND: The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase linked to tumor growth, invasion, and metastasis. FAK is overexpressed and associated with prognosis in many cancers, but its prognostic value in small-cell lung carcinoma (SCLC) is unknown and was the focus of this study. METHODS: Total FAK expression was analyzed via immunohistochemistry in tissue microarrays consisting of formalin-fixed, paraffin-embedded SCLC specimens from 85 patients. FAK staining scores were tested for correlations with pathological characteristics and clinical outcomes. Phospho-paxillin was also tested in 35 of the 85 specimens to evaluate whether FAK expression was associated with downstream signaling. RESULTS: Specific FAK expression was localized to the cytoplasm of 78/85 (92%) SCLCs. FAK expression was scored low in 11 (13%), moderate in 17 (20%), and high in 50 (59%) SCLCs. FAK staining scores treated as continuous variables did not correlate with SCLC disease stage, response to therapy, recurrence/progression-free survival, or overall survival. Moreover, total FAK expression did not correlate with phospho-paxillin Tyr(118) expression. CONCLUSIONS: Total FAK is strongly expressed in a majority of SCLC tumors. However, the expression evaluated via immunohistochemistry is not a prognostic factor in patients with SCLC.

Loss of polymeric immunoglobulin receptor expression is associated with lung tumourigenesis.

Polymeric immunoglobulin receptor (pIgR) expression is downregulated in lung cancer, but its implications in lung tumourigenesis remain unknown. We hypothesised that loss of pIgR expression occurs early, and is associated with cell proliferation and poor prognosis. pIgR expression was evaluated by immunohistochemistry in airways of patients with normal mucosa, pre-invasive lesions and invasive lesions, and correlated with clinical outcomes. 16-HBE and A549 cells stably transfected with pIgR were tested for proliferation, apoptosis and cell cycle progression. Immunostaining was strong in normal epithelium, but severely reduced in pre-invasive lesions and most lung cancers. Persistent expression was associated with younger age and adenocarcinoma subtype but not survival. pIgR overexpression significantly reduced A549 and 16-HBE proliferation. Growth inhibition was not due to cell cycle arrest, increased apoptosis or endoplasmic reticulum stress, but we observed altered expression of genes encoding for membrane proteins, including NOTCH3. Interestingly, NOTCH3 expression was inversely correlated with pIgR expression in cell lines and tissues. pIgR expression was lost in most lung cancers and pre-invasive bronchial lesions, suggesting that pIgR downregulation is an early event in lung tumourigenesis. pIgR overexpression in A549 and 16-HBE cells inhibited proliferation. Future investigations are required to determine the mechanisms by which pIgR contributes to cell proliferation.

Bronchial secretory immunoglobulin a deficiency correlates with airway inflammation and progression of chronic obstructive pulmonary disease.

RATIONALE: Although airway inflammation can persist for years after smoking cessation in patients with chronic obstructive pulmonary disease (COPD), the mechanisms of persistent inflammation are largely unknown. OBJECTIVES: We investigated relationships between bronchial epithelial remodeling, polymeric immunoglobulin receptor (pIgR) expression, secretory IgA (SIgA), airway inflammation, and mural remodeling in COPD. METHODS: Lung tissue specimens and bronchoalveolar lavage were obtained from lifetime nonsmokers and former smokers with or without COPD. Epithelial structural changes were quantified by morphometric analysis. Expression of pIgR was determined by immunostaining and real-time polymerase chain reaction. Immunohistochemistry was performed for IgA, CD4 and CD8 lymphocytes, and cytomegalovirus and Epstein-Barr virus antigens. Total IgA and SIgA were measured by ELISA and IgA transcytosis was studied using cultured human bronchial epithelial cells. MEASUREMENTS AND MAIN RESULTS: Areas of bronchial mucosa covered by normal pseudostratified ciliated epithelium were characterized by pIgR expression with SIgA present on the mucosal surface. In contrast, areas of bronchial epithelial remodeling had reduced pIgR expression, localized SIgA deficiency, and increased CD4(+) and CD8(+) lymphocyte infiltration. In small airways (<2 mm), these changes were associated with presence of herpesvirus antigens, airway wall remodeling, and airflow limitation in patients with COPD. Patients with COPD had reduced SIgA in bronchoalveolar lavage. Air-liquid interface epithelial cell cultures revealed that complete epithelial differentiation was required for normal pIgR expression and IgA transcytosis. CONCLUSIONS: Our findings indicate that epithelial structural abnormalities lead to localized SIgA deficiency in COPD airways. Impaired mucosal immunity may contribute to persistent airway inflammation and progressive airway remodeling in COPD.

Case report: BRAF A598-T599insV mutation as a potential resistance mechanism to alectinib in ALK-rearranged lung adenocarcinoma.

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) have improved the prognosis of advanced-stage non-small cell lung cancer (NSCLC) with ALK rearrangement, but resistance mechanisms limit their efficacy. We describe the case of a 63-year-old man with a stage cIVA ALK-rearranged lung adenocarcinoma who developed a BRAF A598-T599insV mutation as a potential resistance mechanism to alectinib, a second-generation ALK TKI. He was treated with an association of BRAF and MEK inhibitors but death occurred two months after treatment initiation in a context of tumor progression and toxicity. Based on this first report of BRAF A598-T599insV mutation occurring in lung cancer, we discuss resistance mechanisms to ALK TKIs, implications of BRAF mutation in NSCLC, and BRAF A598-T599insV mutation in other cancers.

Targeting BRAF Activation as Acquired Resistance Mechanism to EGFR Tyrosine Kinase Inhibitors in EGFR-Mutant Non-Small-Cell Lung Cancer.

Osimertinib has become a standard of care in the first-line treatment of advanced-stage non-small-cell lung cancer (NSCLC) harboring exon 19 and 21 activating mutations in the EGFR gene. Nevertheless, the 18.9-month median progression-free survival emphasizes the fact that resistance to osimertinib therapy is inevitable. Acquired resistance mechanisms to osimertinib in EGFR-driven NSCLC include MET amplification, EGFR C797S mutation, neuroendocrine differentiation, small-cell lung carcinoma histologic transformation, PD-L1 and KRAS amplifications and ESR1-AKAP12 and MKRN1-BRAF translocations, as well as BRAF V600 mutation. This last one represents 3% of the acquired resistance mechanisms to osimertinib. In this review, we discuss the rationale for EGFR/BRAF/MEK co-inhibition in the light of a clinical case of EGFR-mutant NSCLC developing a BRAF V600 mutation as an acquired resistance mechanism to osimertinib and responding to the association of osimertinib plus dabrafenib and trametinib. Additionally, we discuss the acquired resistance mechanisms to osimertinib plus dabrafenib and trametinib combination in that context.

Bronchotracheal Stenting Management by Rigid Bronchoscopy under Extracorporeal Membrane Oxygenation (ECMO) Support: 10 Years of Experience in a Tertiary Center.

Purpose: Airway stenting offers good palliation and improves the quality of life in patients with inoperable bronchotracheal stenosis. However, in some cases, the management of stenting can be life-threatening. Hence, a strategy for maintaining oxygenation and hemodynamic stability should be anticipated to avoid critical situations. Herein, we report the use of extracorporeal membrane oxygenation (ECMO) in bronchotracheal stenting management to secure oxygenation and facilitate interventions. Methods: We retrospectively reviewed all patients who underwent rigid bronchoscopy under ECMO support for the management of bronchotracheal stenting at CHU UCL Namur hospital (Belgium), between January 2009 and December 2019. Results: We included 14 bronchoscopy cases performed on 11 patients (3 patients underwent 2 bronchoscopies) in this study; 12 were performed on males and 2 on females. The median age was 54 years. There were 11 benign and 3 malignant etiologies for the central airway obstruction/stenosis. Eight cases were supported by venovenous ECMO and six by venoarterial ECMO. The median ECMO time was 267 minutes. The weaning of ECMO support was successful in all cases. In most cases, the procedures were performed effectively and safely. Only two local complications caused by the cannulation of ECMO were reported, and anticoagulation was adapted to avoid bleeding at the operating site and clot formation in the system. Conclusion: Elective ECMO support was helpful and safe for the high-risk management of bronchotracheal stenting with rigid bronchoscopy and was not associated with any additional significant complications.

Therapeutic depletion of CCR8+ tumor-infiltrating regulatory T cells elicits antitumor immunity and synergizes with anti-PD-1 therapy.

BACKGROUND: Modulation and depletion strategies of regulatory T cells (Tregs) constitute valid approaches in antitumor immunotherapy but suffer from severe adverse effects due to their lack of selectivity for the tumor-infiltrating (ti-)Treg population, indicating the need for a ti-Treg specific biomarker. METHODS: We employed single-cell RNA-sequencing in a mouse model of non-small cell lung carcinoma (NSCLC) to obtain a comprehensive overview of the tumor-infiltrating T-cell compartment, with a focus on ti-Treg subpopulations. These findings were validated by flow cytometric analysis of both mouse (LLC-OVA, MC38 and B16-OVA) and human (NSCLC and melanoma) tumor samples. We generated two CCR8-specific nanobodies (Nbs) that recognize distinct epitopes on the CCR8 extracellular domain. These Nbs were formulated as tetravalent Nb-Fc fusion proteins for optimal CCR8 binding and blocking, containing either an antibody-dependent cell-mediated cytotoxicity (ADCC)-deficient or an ADCC-prone Fc region. The therapeutic use of these Nb-Fc fusion proteins was evaluated, either as monotherapy or as combination therapy with anti-programmed cell death protein-1 (anti-PD-1), in both the LLC-OVA and MC38 mouse models. RESULTS: We were able to discern two ti-Treg populations, one of which is characterized by the unique expression of Ccr8 in conjunction with Treg activation markers. Ccr8 is also expressed by dysfunctional CD4+ and CD8+ T cells, but the CCR8 protein was only prominent on the highly activated and strongly T-cell suppressive ti-Treg subpopulation of mouse and human tumors, with no major CCR8-positivity found on peripheral Tregs. CCR8 expression resulted from TCR-mediated Treg triggering in an NF-κB-dependent fashion, but was not essential for the recruitment, activation nor suppressive capacity of these cells. While treatment of tumor-bearing mice with a blocking ADCC-deficient Nb-Fc did not influence tumor growth, ADCC-prone Nb-Fc elicited antitumor immunity and reduced tumor growth in synergy with anti-PD-1 therapy. Importantly, ADCC-prone Nb-Fc specifically depleted ti-Tregs in a natural killer (NK) cell-dependent fashion without affecting peripheral Tregs. CONCLUSIONS: Collectively, our findings highlight the efficacy and safety of targeting CCR8 for the depletion of tumor-promoting ti-Tregs in combination with anti-PD-1 therapy.