Involvement of PD-1+CD4+ T cells in the development of traumatic tracheal stenosis by regulating the IL-17/STAT3 pathway.

Studies have highlighted an upregulation of PD-1 expression in CD4+ T cells, which accelerates lung fibrosis by activating the IL-17/STAT3 pathway, leading to IL-17A and TGF-ß1 secretion. However, the relation with traumatic tracheal stenosis (TS) remains unexplored. Our analysis found significant increases in PD-1+CD4+ T cells, IL-17A, and TGF-ß1 in the TS patients (n = 10). The cellular model used CD4+ T cells co-cultured with bronchial fibroblasts while the animal model used a nylon brush to scrape the damaged tracheal mucosa. Interventions with PD-1 and STAT3 inhibitors both in vitro (n = 5) and in vivo (n = 6) showed decreased expression of TGF-ß1 and IL-17A in CD4+ T cells, decreased collagen I synthesis in vitro, and reduced tractal fibrosis in vivo. Furthermore, PD-1's modulation of the STAT3 was evident. This research unveils PD-1+CD4+ T cells' role in TS, thus suggesting a novel immunotherapeutic strategy to counteract tracheal fibrosis.

Increased Expression of PD-1 and PD-L1 in Patients With Laryngotracheal Stenosis.

OBJECTIVES: Laryngotracheal stenosis (LTS) is a fibrotic condition of the upper airway. Recent evidence suggests dysregulated host immunity plays a role in LTS development and progression. The programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis, targeted by paradigm-shifting immunotherapies for cancer treatment, has also recently been implicated in the pathogenesis of fibrotic pulmonary disease. However, a role for the PD-1/PD-L1 axis in the proximal airway fibrosis seen in LTS patients has not been explored. STUDY DESIGN: Controlled ex vivo study. METHODS: Expression of PD-1, PD-L1, CD4, and CD8 were evaluated using immunohistochemical staining of cricotracheal resection specimens from postintubation iatrogenic laryngotracheal stenosis (iLTS), idiopathic subglottic stenosis (iSGS) patients, and normal controls derived from rapid autopsy (n = 8 per group). Fibroblasts derived from iLTS scar were also treated with transforming growth factor beta 1 (TGFß1) and analyzed for PD-L1 expression by quantitative real-time polymerase chain reaction (n = 6). RESULTS: iLTS specimens exhibited increased expression of PD-1, PD-L1, and CD4 (all P < .0167) compared to controls, whereas iSGS specimens exhibited increased expression of PD-1 and CD4 (P < .0167) compared to controls. PD-1, PD-L1, and CD4 showed periepithelial patterns of expression in both disease cohorts. TGFß1 treatment of iLTS fibroblasts increased expression of PD-L1 (the cognate ligand for PD-1). CONCLUSION: Expression of both PD-1 and its ligand PD-L1 are significantly greater in patients with iLTS compared to controls, and PD-1 expression is also elevated in patients with iSGS. Given published evidence implicating the PD-1/PD-L1 axis in pulmonary fibrosis, this suggests a possible role for checkpoint inhibitors targeting the PD-1/PD-L1 axis for the treatment of LTS. LEVEL OF EVIDENCE: N/A Laryngoscope, 131:967-974, 2021.

M2 Macrophages Promote Collagen Expression and Synthesis in Laryngotracheal Stenosis Fibroblasts.

OBJECTIVE: Macrophages exhibit distinct phenotypes and are dysregulated in a model of iatrogenic laryngotracheal stenosis (iLTS). Increased populations of alternatively activated or M2 macrophages have been demonstrated. However, the role of these macrophages is unknown. The aims of this study are: 1) define the macrophage population in iLTS in the context of classically activated or M1 and M2 macrophage phenotypes, and 2) characterize the effect of monocyte-derived M1 and M2 macrophages on normal airway and LTS-derived fibroblasts (FBs) in vitro. STUDY DESIGN: Comparative analysis; in vitro controlled study. METHODS: Immunohistochemical analysis of human iLTS and control specimens was performed to define the macrophage population. In vitro, M1, and M2 macrophages were polarized using M-CSF + Interferon-gamma and lipopolysaccharide or Interleukin-4, respectively. FBs isolated from laryngotracheal scar (LTS-FBs) and normal tracheal airway (NA-FBs) in eight patients with iLTS were cocultured with polarized macrophages. Fibrosis gene expression, soluble collagen production, and proliferation were assessed. RESULTS: Immunohistochemical analysis revealed increased CD11b + cells (macrophage marker) in laryngotracheal scar specimens (18.3% vs. 8.5%, P = .03) and predominant CD206 (M2) costaining versus CD86 (M1) (51.5% vs. 9.8%, n = 10, P = .001). In vitro, NA-FBs cultured with M2 macrophages demonstrated a 2.41-fold increase in collagen-1 expression (P = .05, n = 8) and an increase in soluble collagen (9.98 vs. 8.875, mean difference: 1.11 95%, confidence interval 0.024-2.192, n = 8, P = .015). CONCLUSION: Increased populations of CD11b cells are present in iLTS specimens and are predominantly CD206+, indicating an M2 phenotype. In vitro, M2 macrophages promoted collagen expression in airway FBs. Targeting macrophages may represent a therapeutic strategy for attenuating fibrosis in iLTS. LEVEL OF EVIDENCE: NA Laryngoscope, 131:E346-E353, 2021.

Quantitative Assessment of the Immune Microenvironment in Patients With Iatrogenic Laryngotracheal Stenosis.

OBJECTIVE: Iatrogenic laryngotracheal stenosis (iLTS) is characterized by fibroinflammatory narrowing of the upper airway and is most commonly caused by intubation injury. Evidence suggests a key role for CD4 T cells in its pathogenesis. The objective of this study is to validate emerging multiplex immunofluorescence (mIF) technology for use in the larynx and trachea while quantitatively characterizing the immune cell infiltrate in iLTS. In addition to analyzing previously unstudied immune cell subsets, this study aims to validate previously observed elevations in the immune checkpoint PD-1 and its ligand PD-L1 while exploring their spatial and cellular distributions in the iLTS microenvironment. STUDY DESIGN: Controlled ex vivo cohort study. SETTING: Tertiary care center. METHODS: mIF staining was performed with formalin-fixed, paraffin-embedded slides from 10 patients with iLTS who underwent cricotracheal resection and 10 control specimens derived from rapid autopsy for CD4, CD8, CD20, FoxP3, PD-1, PD-L1, and cytokeratin. RESULTS: There was greater infiltration of CD4+ T cells, CD8+ T cells, CD20+ B cells, FoxP3+CD4+ Tregs, and FoxP3+CD8+ early effector T cells in the submucosa of iLTS specimens as compared with controls (P < .05 for all). PD-1 was primarily expressed on T cells and PD-L1 predominantly on CD4+ cells and "other" cells. CONCLUSION: This study leverages the power of mIF to quantify the iLTS immune infiltrate in greater detail. It confirms the highly inflammatory nature of iLTS, with CD4+ cells dominating the immune cell infiltrate; it further characterizes the cellular and spatial distribution of PD-1 and PD-L1; and it identifies novel immunologic targets in iLTS.

Role of Erythromycin-Regulated Histone Deacetylase-2 in Benign Tracheal Stenosis.

Objective: This study aims to explore the role of erythromycin-regulated histone deacetylase-2 in benign tracheal stenosis. Methods: The rabbit model of tracheal stenosis was established. The rabbits were randomly divided into 8 groups. Histone deacetylase-2 (HDAC2) expression was detected by immunofluorescence. The expression of type I collagen and type III collagen was detected by immunohistochemical method. The expression of TGF-ß1, VEGF and IL-8 in serum and alveolar lavage fluid was detected by ELISA. The expression of HDAC2, TGF-ß1, VEGF and IL-8 in serum and alveolar lavage fluid was detected by ELISA. The expression of HDAC2, TGF. Results: In Erythromycin (ERY) group, ERY + Budesonide group, ERY + Vorinostat group and ERY + Budesonide + Vorinostat group, the degree of bronchial stenosis was alleviated, and the mucosal epithelium was still slightly proliferated. The effect of ERY combined with other drugs was more obvious. The HDAC2 protein expression increased significantly in ERY group, ERY + Budesonide group and ERY + Budesonide + Vorinostat group and decreased significantly in Vorinostat group, the expression of collagen I and III decreased significantly in ERY group, ERY + Budesonide group and ERY + Budesonide + Vorinostat group (P < 0.05). The TGF-ß1, VEGF and IL-8 in serum and alveolar lavage fluid was detected by ELISA. The expression of HDAC2, TGF-P < 0.05). The TGF. Conclusions: Erythromycin inhibited inflammation and excessive proliferation of granulation tissue after tracheobronchial mucosal injury by up-regulating the expression of HDAC2, it promoted wound healing and alleviated tracheobronchial stenosis. When combined with budesonide, penicillin and other glucocorticoids and antibiotics, it had a good synergistic effect. However, vorinostat could attenuate erythromycin's effect by down-regulating the expression of HDAC2. It may have good clinical application prospects in the treatment of tracheal stenosis.

T-Helper 2 Lymphocyte Immunophenotype Is Associated With Iatrogenic Laryngotracheal Stenosis.

OBJECTIVE/HYPOTHESIS: This prospective controlled human and murine study assessed the presence of inflammatory cells and cytokines to test the hypothesis that immune cells are associated with fibroproliferation in iatrogenic laryngotracheal stenosis (iLTS). METHODS: Inflammation was assessed by histology and immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR), and flow cytometry of cricotracheal resections of iLTS patients compared to normal controls. An iLTS murine model assessed the temporal relationship between inflammation and fibrosis. RESULTS: iLTS specimens showed increased inflammation versus normal controls (159/high power field [hpf] vs. 119/hpf, P = 0.038), and increased CD3 + T-cells, CD4 + cells, and CD3+/CD4 + T-helper (TH ) cells (all P < 0.05). The inflammatory infiltrate was located immediately adjacent to the epithelial surface in the superficial aspect of the thickened lamina propria. Human flow cytometry and qRT-PCR showed a significant increase in interleukin (IL)-4 gene expression, indicating a TH 2 phenotype. Murine IF revealed a dense CD4 + T-cell inflammatory infiltrate on day 4 to 7 postinjury, which preceded the development of fibrosis. Murine flow cytometry and qRT-PCR studies mirrored the human ones, with increased T-helper cells and IL-4 in iLTS versus normal controls. CONCLUSION: CD3/CD4 + T-helper lymphocytes and the proinflammatory cytokine IL-4 are associated with iLTS. The association of a TH 2 immunophenotype with iLTS is consistent with findings in other fibroinflammatory disorders. The murine results reveal that the inflammatory infiltrate precedes the development of fibrosis. However, human iLTS specimens with well-developed fibrosis also contain a marked chronic inflammatory infiltrate, suggesting that the continued release of IL-4 by T-helper lymphocytes may continue to propagate iLTS. LEVEL OF EVIDENCE: NA Laryngoscope, 129:177-186, 2019.

Autoimmune Tracheal Cartilage Inflammation Responsive to Anti-TNF-α Therapy.

Tracheal inflammation, or tracheitis, is a pathologic process that can occur secondary to a number of systemic inflammatory diseases, or it may be idiopathic in nature. Regardless of the underlying etiology, tracheitis can, in its most severe form, be life-threatening, thus making its treatment an area of interest. Our case is one of a 50-year-old man with a remote history of inflammatory bowel disease achieving clinical cure following surgical resection who presented with progressive dyspnea due to tracheal stenosis that was presumed secondary to an autoimmune and inflammatory etiology. His disease was initially refractory to recurrent surgical interventions. He ultimately achieved clinical improvement with a combination of methotrexate and the tumor necrosis factor alpha (TNF-α) inhibitor, adalimumab. While both clinical trials and standardized treatment guidelines are lacking in this domain, this case illustrates a potential role for TNF-α inhibitors in the treatment of inflammatory tracheitis, irrespective of the underlying etiology.

Quantification of Inflammatory Markers in Laryngotracheal Stenosis.

Objectives (1) Develop a novel method for serial assessment of gene and protein expression in laryngotracheal stenosis (LTS). (2) Assess cytokine expression and determine an immunophenotype in LTS. Study Design A matched comparison of endolaryngeal brush biopsy samples from laryngotracheal scar and normal airway. Setting Tertiary care hospital, 2015-2016. Methods Brush biopsy specimens of laryngotracheal scar and normal trachea were obtained from 17 patients with LTS at the time of operating room dilation and were used for protein and RNA extraction. Gene expression of the TH1 cytokine interferon γ (INF-γ), TH2 cytokine interleukin 4 (IL-4), transforming growth factor ß, and collagen 1 (Coll1) was quantified with quantitative real-time polymerase chain reaction. Cytokine analysis was performed with flow cytometry with a cytometric bead array. Results LTS specimens demonstrated a 13.68-fold increase in Coll1 gene expression versus normal ( P < .001, N = 17). Additionally, IL-4 gene expression showed a 3.76-fold increase ( P < .001, N = 17) in LTS scar. When stratified into iatrogenic LTS and idiopathic subglottic stenosis cohorts, INF-γ gene expression was significantly increased in idiopathic subglottic stenosis ( P = .011). Soluble cytokine measurements were below the limit of detection for reliable quantification and thus could not be assessed. Conclusions Brush biopsies from LTS samples can be successfully utilized for RNA extraction and demonstrate the expected increase in Coll1 gene expression associated with LTS. Preliminary gene expression suggests that abnormal collagen production may be mediated by the TH2 cytokine IL-4 and that increased INF-γ expression may represent a key difference between iatrogenic LTS and idiopathic subglottic stenosis. Further analysis of soluble cytokines is needed to confirm these findings.

Stent-induced tracheal stenosis can be predicted by IL-8 expression in rabbits.

BACKGROUND: Bare metal stents may cause complications like fibrous encapsulation, granulation and tracheal stenosis. We investigated the behaviour of three commercially available stents in vivo (rabbits) and in vitro (coculture of those stents with epithelial and fibroblast cell lines). Also, we investigated whether development of tracheal stenosis could be predicted by any biological marker. MATERIALS AND METHODS: The tracheae of 30 rabbits were implanted with either nitinol stents, with or without paclitaxel elution, or a cobalt-based stent. An additional ten rabbits underwent mock implantation (controls). Serial peripheral venous blood samples were taken throughout the study, and several cytokines measured. Animals were euthanized on day 90, with immediate tracheal endoscopy and lavage performed, then necropsy. RESULTS: Rabbits with cobalt-based stent exhibited more inflammation and the highest stenosis incidence, with reduced survival. Both in vivo and in vitro, this stent induced higher IL-8 levels than nitinol stents. Most important, the presence of stent-induced tracheal stenosis was closely associated to increase in IL-8 expression in blood just 1 day after tracheal stent implantation: a 1·19-fold increase vs. baseline had 83% sensitivity, 83% specificity, 77% positive predictive value, 88% negative predictive value and 83% accuracy to predict development of stenosis. CONCLUSIONS: The cobalt-based stent had the highest incidence of tracheal inflammation and stenosis. On the other hand, the paclitaxel-eluting nitinol stent did not prevent those complications and provoked a marked reaction compared with the bare nitinol stent. Early increase in IL-8 expression in blood after stent implantation could predict development of tracheal stenosis in rabbits.

Laryngotracheal stenosis of autoimmune aetiology. / Estenosis laringotraqueales de etiología autoinmune.

Autoimmune origin ranks fifth in the etiologic classification of laryngotracheal stenosis. Wegener's disease is the autoimmune illness most associated with stenosis; however, there are other autoimmune diseases that may also be associated with it. A descriptive, retrospective study of 9 cases of laryngotracheal stenosis associated with autoimmune disease was carried out. There were 9 patients (8 females and 1 male) with an average age of 27.9 years. Four of the patients suffered from Wegener's disease, 1 from ulcerative colitis and 1 from purple vasculitis. The other 3 patients only had positive c-ANA. Endoscopic treatment was performed in 3 cases. The other 6 patients required open surgery. Respiratory results were acceptable. Based on our study, we feel that the immunological profiles should be studied in all patients with stenosis, given that not only Wegener's disease is linked to stenosis.

Apoptosis of the Tracheal Epithelium Can Increase the Number of Recipient Bone Marrow-Derived Myofibroblasts in Allografts and Exacerbate Obliterative Bronchiolitis After Tracheal Transplantation in Mice.

BACKGROUND: The long-term outcome of lung transplantation is impeded by the development of obliterative bronchiolitis (OB). We sought to investigate the relationship between the apoptosis of tracheal epithelial cells and bone marrow-derived myofibroblasts in the process of OB. METHODS: The mouse orthotopic tracheal transplant model was established. The allografts and syngrafts were harvested at 1, 2, 3, and 4 weeks after tracheal transplant. The percentage of tracheal lumen occlusion was assayed via histology and morphometry. Immunofluorescence staining was used to detect the apoptotic epithelial cells and recipient-derived myofibroblasts. The expression of SDF-1α and TGF-ß and the infiltrations of CD4 and CD8 T cells in the grafts were detected using immunohistochemical staining. RESULTS: We found that there were more apoptotic epithelia in the allograft group than in the syngraft group and that the level of tracheal lumen occlusion was higher at different time points. Moreover, the increase in the apoptosis of the tracheal epithelium occurred earlier than that of occlusion of the tracheal lumen. There were more myofibroblasts derived from the recipient's bone marrow and more CD4 and CD8 T cells in the allografts. The expression of SDF-1α and TGF-ß was higher in the epithelium from allografts than in those of the syngrafts. CONCLUSIONS: Our study indicated that the apoptotic tracheal epithelia in the OB model might increase the amount of myofibroblasts derived from the recipient's bone marrow. Therapeutic methods aimed at preventing apoptosis of the tracheal epithelium may improve the outcome of lung transplantation.

Electroporation-mediated transfer of plasmid DNA encoding IL-10 attenuates orthotopic tracheal allograft stenosis in rats.

BACKGROUND: Electroporation has been shown to increase the efficacy of intramuscular injection of plasmid DNA, resulting in a higher level of foreign gene expression. Using this technique, we examined the effect of viral IL-10 gene transfer on the prevention of tracheal allograft stenosis in an animal model. METHODS: On the day of tracheal transplantation, recipient Lewis rats were intramuscularly injected with either plasmid pCAGGS-LacZ or plasmid pCAGGS-viral IL-10, followed immediately by electroporation. Tracheas from Brown Norway donors were transplanted into the backs of Lewis recipients, and the histology of the grafts were assessed 2 and 4 weeks after transplantation. RESULTS: The serum level of IL-10 peaked at 2000 pg/ml one day after injection; the level then slowly decreased, but was maintained above 1000 pg/ml until 8 days after injection. At Day 28, the airway lumina of the tracheal allografts were almost completely obliterated by fibroproliferative tissue in the control pCAGGS-LacZ-treated rats. In rats injected once with pCAGGS-viral IL-10, luminal obliteration was significantly decreased compared with the control pCAGGS-LacZ-treated rats (mean luminal opening 46.8% vs 0% p<0.05). The loss of epithelial cells lining the airway was also decreased in the IL-10-treated group (mean epithelial coverage 42% vs 5% p<0.05). Multiple injections with pCAGGS-viral IL-10 did not further improve the histological changes. CONCLUSION: IL-10 gene transfer by intramuscular injection using electroporation attenuated tracheal allograft stenosis associated with mild epithelial injury.

[The immune status and its correction in patients after reconstructive surgeries for cicatricial stenosis of trachea]. / Immunnyi status i ego korrektsiia u bol'nykh posle rekonstruktivnykh operatsii po povodu rubtsovogo stenoza trakhei.

The immune status was analyzed in 28 patients with cicatricial stenosis of the trachea for the purpose of determining the type and nature of affection as well as for the purpose of evaluating the clinical efficiency of galavit immunomodulator. Combined impairments were diagnosed in the patients. Moderately decreased CD4+, CD8+, CD16+, significantly decreased CD25+, HLA-DR, CD71+ and increased CD4+/CD8+ were detected at the cell level. An essentially lower CD20+, a higher content of IgG and a reduced FAN were observed in the humoral chain. Therefore, galavit, when used preoperative and immediately after surgery in patients with cicatricial stenosis of the trachea, had a positive effect on the immune status; it reliably increased the count of T-helpers (CD4+) and of natural killers (CD16+) and it induced the phagocyte activity of neutrophils.

[Immunity in children with aquired cicatricial stenoses of the larynx and cervical trachea. Communication 3. Condition of phagocyting immune system]. / Pokazateli immuniteta u detei s priobretennym rubtsovym stenozom gortani i sheinogo otdela trakhei. Soobshchenie 3. Sostoianie fagotsitiruiushchei sistemy immuniteta.

Macrophagal-phagocyting immunity was studied in 59 children with cicatricial acquired stenosis of the larynx and cervical trachea aged 1 year 9 months to 14 years 8 months. It was found that children with acquired cicatricial stenosis had a sharp depression of all functions of the cells of the macrophagal-phagocyting system (chemotaxis, absorptive, digestive, oxidation-reduction) as well as reduction of their number. This is, on the one hand, a defense reaction of the organism to continuous antigenic stimulation; on the other hand, this marks feasibility of progressive immunocomplex and/or autoimmune processes. The most prominent alterations were seen in patients with concurrent affection of the CNS.

[Tracheal stenosis and autoimmune thyroiditis]. / Trakeal stenose og autoimmun tyreoiditt.

After exposure to ammonia, a 63 year old woman experienced dyspnoea and respiratory infections. A stenosis was diagnosed in the proximal part of the trachea. High levels of antibodies against thyroperoxidase suggested thyroiditis. After treatment with corticosteroids both the antibodies and the stenosis decreased and the patient's symptoms improved. A few months later the patient developed therapy-resistant uveitis. Cyclosporin was added to the treatment and the condition was stabilized. The diagnosis was unclear. Tracheal stenosis may have developed secondary to autoimmune thyroiditis, while the uveitis probably was another organ manifestation of the autoimmune disease. The ammonia may have caused mucosal oedema, increasing the obstruction to symptomatic level.

[Autoantibodies against cartilage components: clinical relevance for reconstructive surgery in the area of the head and neck]. / Autoantikörper gegen Knorpelbestandteile: Klinische Relevanz für die rekonstruktive Chirurgie im Kopf-Hals-Bereich.

The clinical relevance of antibodies against components of cartilage in the reconstructive surgery has not yet been clarified. In our study four groups of patients with successful and unsuccessful autologous cartilage transplantation in rhinosurgery, patients with ear perichondritis and patients with tracheal stenosis after long-term intubation were investigated for the presence of a humoral immune reactivity to cartilage. The control groups consisted of healthy persons and patients with RA. The antibodies against cartilage matrix and chondrocytes were determined using indirect immunofluorescence methods. Patients with unsuccessful cartilage transplantation showed increased antibodies against autologous cartilage (until 1:100) compared to the patients with successful cartilage transplantation. Furthermore, patients suffering from ear perichondritis and tracheal stenosis showed also increased antibodies against cartilage. These data suggest that a humoral immune reactivity against autologous cartilage--independent of an infection--can be one cause for the destruction of cartilaginous tissue.

[Immunologic behavior of human tracheal transplants]. / Immunologisches Verhalten menschlicher Trachealtransplantate.

In this study we tried to investigate the antigenicity of human tracheal allografts. We found transplantation antigens in the mucosa and the mixed glands using monoclonal antibodies in an indirect immunoperoxidase method. However these antigens were able to be destroyed with a chemical preservation procedure. The diminution of the antigenicity could be also achieved in a tracheal transplant human recipient. These results show that the preserved trachea may be immunologically a suitable material for reconstruction in surgery of the trachea.

[Antibodies to type I and II collagen in rheumatoid arthritis and chronic cicatricial stenosis of the larynx and trachea in children]. / Antitela k kollagenam I i II tipov pri revmatoidnom artrite i khronicheskom rubtsovom stenoze gortani i trakhei u detei.

Enzyme immunoassay with highly purified human collagen preparations and low (1:10) dilutions of sera detected an increased specific immune reaction mostly on collagen denaturated forms in 50% of 49 patients with rheumatoid arthritis. No correlation was detected between the level of humoral immune response and the major clinical parameters except those reflecting the disease progress. Similar investigation of sera from children with chronic cicatricial stenoses has revealed a group of patients with significantly elevated level of anticollagen humoral immune response, though in these patients this response is probably not specifically associated with collagen.