Persistent Inflammation and Nitric Oxide Dysregulation Are Transcriptomic Blueprints of Subglottic Stenosis.

Subglottic stenosis (SGS) is a recurrent, obstructive, fibroinflammatory disease of the upper airway resulting in severe dyspnea, dysphonia, as well as other potentially fatal complications. Although aberrant inflammation and wound-healing are commonly associated with pathogenesis, the mechanism through which such processes occur and recur in affected patients remains poorly studied. Here we report that transcriptomic profiling of laryngotracheal regions from minimally-invasive mucosal swabs of SGS patients reveals a distinctively pro-inflammatory gene signature. Surprisingly, comparative genomics between SGS patients and mice with direct laryngotracheal injury suggest that SGS patients bear more resemblance to the acute than chronic phase of injury. Furthermore, functional and regulatory network analyses identify neutrophilic involvement through hyper-activation of NF-κB and its downstream inflammasome as a potential master regulator. Interestingly, nitric oxide synthesis was found to be downregulated in SGS patients compared to healthy controls. Thus, SGS represents a state of immunodeficiency whereby defective immune clearance triggers recurrent, long-lasting production of pro-inflammatory cytokines.

Sirolimus use in patients with subglottic stenosis in the context of granulomatosis with polyangiitis (GPA), suspected GPA, and immunoglobulin G4-related disease.

Objective: Subglottic stenosis (SGS) is a severe, life-threatening disease found in immune-mediated diseases such as granulomatosis with polyangiitis (GPA) and in rare cases of immunoglobulin G4 (IgG4)-related disease. It can result in persistent airway compromise due to the fibrotic response following inflammation. Standard management involves repeated endoscopic interventions to dilate the airway, and tracheostomy is occasionally required. In addition, immunosuppression remains a cornerstone of therapy aimed at controlling the underlying inflammatory disease; however, cumulative dosing leads to significant adverse effects. We present five cases of predominantly anti-neutrophil cytoplasmic antibody-negative GPA and a case of IgG4-related disease with SGS, in whom we evaluated the long-term utility of sirolimus, which has beneficial anti-proliferative and fibrotic effects, in the management of their disease. Method: We conducted a retrospective review of a cohort of patients with SGS at a tertiary vasculitis unit. These patients were treated with sirolimus, in addition to conventional medical and endoscopic treatment. Clinical symptoms, frequency and time to endoscopic intervention pre- and post-treatment, additional rescue therapy, and any adverse effects were recorded and analysed. Results: Six patients were treated with sirolimus and followed for up to 9 years; two discontinued the drug owing to adverse effects, early on. In the remaining four patients, glucocorticoids were withdrawn, and the frequency of endoscopic intervention was reduced. One patient on sirolimus required rituximab therapy for disease flare. Conclusion: Sirolimus may be a therapeutic option for some patients with severe SGS, allowing steroid withdrawal and resulting in a positive adverse effect profile.

The Proximal Airway Is a Reservoir for Adaptive Immunologic Memory in Idiopathic Subglottic Stenosis.

OBJECTIVES/HYPOTHESIS: Characterization of the localized adaptive immune response in the airway scar of patients with idiopathic subglottic stenosis (iSGS). STUDY DESIGN: Basic Science. METHODS: Utilizing 36 patients with subglottic stenosis (25 idiopathic subglottic stenosis [iSGS], 10 iatrogenic post-intubation stenosis [iLTS], and one granulomatosis with polyangiitis [GPA]) we applied immunohistochemical and immunologic techniques coupled with RNA sequencing. RESULTS: iSGS, iLTS, and GPA demonstrate a significant immune infiltrate in the subglottic scar consisting of adaptive cell subsets (T cells along with dendritic cells). Interrogation of T cell subtypes showed significantly more CD69+ CD103+ CD8+ tissue resident memory T cells (TRM ) in the iSGS airway scar than iLTS specimens (iSGS vs. iLTS; 50% vs. 28%, P = .0065). Additionally, subglottic CD8+ clones possessed T-cell receptor (TCR) sequences with known antigen specificity for viral and intracellular pathogens. CONCLUSIONS: The human subglottis is significantly enriched for CD8+ tissue resident memory T cells in iSGS, which possess TCR sequences proven to recognize viral and intracellular pathogens. These results inform our understanding of iSGS, provide a direction for future discovery, and demonstrate immunologic function in the human proximal airway. Laryngoscope, 131:610-617, 2021.

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.

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.

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.

Differing Progression to Posterior Glottic Stenosis in Autoimmune and Idiopathic Subglottic Stenosis.

OBJECTIVES/HYPOTHESIS: We sought to characterize rates of progression to posterior glottic stenosis (PGS) from autoimmune or idiopathic subglottic stenosis. STUDY DESIGN: This was a retrospective review. METHODS: Patients from a tertiary-care laryngology practice over a 10-year period with autoimmune or idiopathic subglottic stenosis (SGS) were included. Patients with a history of prolonged intubation or other causes of iatrogenic stenosis were excluded. PGS was confirmed on videostrobolaryngoscopy recordings by a fellowship-trained laryngologist. PGS type (1-4) was also recorded. Demographic information was recorded, and if applicable, autoimmune disease type was specified. Time until PGS was recorded along with the number of interventions. Chi-squared analysis was used to compare PGS in autoimmune and idiopathic SGS. RESULTS: A total of 77 patients were identified with autoimmune (32 patients) or idiopathic (45 patients) subglottic stenosis. Autoimmune pathologies included systemic lupus erythematosus, granulomatosis with polyangiitis (GPA), rheumatoid arthritis, relapsing polychondritis, and sarcoidosis, with GPA the most common (14/32). Patients with autoimmune SGS had a higher rate of PGS (10 of 32) compared to idiopathic subglottic stenosis (1 of 45) for an odds ratio of 20 (95% CI: 2.4-166.4, P = .006). Patients with idiopathic SGS were more likely to be female (all 45 compared to 29/32 autoimmune, P = .07) and older (mean 53 (range 29-75) compared to 46 (20-82), P = .02). CONCLUSIONS: In this large patient cohort, autoimmune SGS patients were found to have a higher likelihood of developing PGS compared to their idiopathic counterparts, suggesting that counseling for this progression may be warranted. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:1816-1820, 2021.

The presence of staphylococcal superantigens in nasal swabs and correlation with activity of granulomatosis with polyangiitis in own material.

OBJECTIVES: Nasal carriage of Staphylococcus aureus and its superantigens (SAg) seem to be a risk factor disease exacerbation in granulomatosis with polyangiitis (GPA). We investigated the association between the presence of SAg in nasal swabs and activity of disease in GPA patients also taking into account correlation with an antimicrobial treatment. METHODS: In a prospective study of a total of 150 GPA patients hospitalised in the period 2009-2016, nasal swabs were examined for the presence of Staphylococcus aureus and SAg. Subsequently, the association with disease activity was assessed. RESULTS: Of 362 Staphylococcus aureus-positive nasal swab cultures from 115 of the 150 patients, the presence of at least one SAg in 126 samples (34.8%) from 56 patients (48.7%) was found. Among the 17 patients with limited to subglottic stenosis (SGS) disease, SAg were detected in 6 cases (35.3%). We did not find a significant correlation between the presence of SAg and disease activity (p=0.986), although when individual SAg were analysed separatively, SED and TSST-1 were more frequently present in active disease. Additionally, the results of the analysis demonstrated a protective effect of trimethoprim/sulfamethoxazole (T/S) treatment (0R 0.52, p<0.0092) in GPA patients. Interestingly, GPA limited to SGS appeared as an unfavourable factor associated with disease activity (0R 1.84, p=0.05). CONCLUSIONS: The association between staphylococcal SAg in nasal swabs and GPA activity is not evident. Multiple mechanisms that may lead to disease activation still need to be investigated.

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.

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.

Rapamycin inhibits human laryngotracheal stenosis-derived fibroblast proliferation, metabolism, and function in vitro.

OBJECTIVE: To determine if rapamycin inhibits the growth, function, and metabolism of human laryngotracheal stenosis (LTS)-derived fibroblasts. STUDY DESIGN: Controlled in vitro study. SETTING: Tertiary care hospital in a research university. SUBJECTS AND METHODS: Fibroblasts isolated from biopsies of 5 patients with laryngotracheal stenosis were cultured. Cell proliferation, histology, gene expression, and cellular metabolism of LTS-derived fibroblasts were assessed in 4 conditions: (1) fibroblast growth medium, (2) fibroblast growth medium with dimethylsulfoxide (DMSO), (3) fibroblast growth medium with 10(-10) M (low-dose) rapamycin dissolved in DMSO, and (4) fibroblast growth medium with 10(-9) M (high-dose) rapamycin dissolved in DMSO. RESULTS: The LTS fibroblast count and DNA concentration were reduced after treatment with high-dose rapamycin compared to DMSO (P = .0007) and normal (P = .0007) controls. Collagen I expression decreased after treatment with high-dose rapamycin versus control (P = .0051) and DMSO (P = .0093) controls. Maximal respiration decreased to 68.6 pMoles of oxygen/min/10 mg/protein from 96.9 for DMSO (P = .0002) and 97.0 for normal (P = .0022) controls. Adenosine triphosphate (ATP) production decreased to 66.8 pMoles from 88.1 for DMSO (P = .0006) and 83.3 for normal (P = .0003) controls. Basal respiration decreased to 78.6 pMoles from 108 for DMSO (P = .0002) and 101 for normal (P = .0014) controls. CONCLUSIONS: Rapamycin demonstrated an anti-fibroblast effect by significantly reducing the proliferation, metabolism, and collagen deposition of human LTS fibroblast in vitro. Rapamycin significantly decreased oxidative phosphorylation of LTS fibroblasts, suggesting at a potential mechanism for the reduced proliferation and differentiation. Furthermore, rapamycin's anti-fibroblast effects indicate a promising adjuvant therapy for the treatment of laryngotracheal stenosis.

Cellular adaptive inflammation mediates airway granulation in a murine model of subglottic stenosis.

OBJECTIVE: To determine the contribution of B- and T-cell-mediated inflammation in a murine airway granulation model. STUDY DESIGN: Pilot study in a modified murine model. SETTING: Philadelphia VA Medical Center Research Building. SUBJECTS AND METHODS: Laryngotracheal complexes (LTCs) from 54 donor C57BL/6 mice were harvested and divided into 3 groups: (1) uninjured, (2) mechanically injured using a wire brush, and (3) chemically injured using hydrochloric acid. One donor LTC from each group was placed in deep dorsal subcutaneous pockets of either severe combined immunodeficiency (SCID)- or C57BL-recipient mice, for a total of 3 transplanted tracheas per recipient mouse. After 3 weeks, the transplanted LTCs were harvested from both C57BL- and SCID-recipient mice. Tissues were fixed, sectioned, and stained with hematoxylin and eosin. Representative slides were reviewed by a blinded pathologist to determine the formation of granulation tissue and graded as to the degree of formation of granulation tissue. RESULTS: Despite significant granulation formation in C57BL-recipient mice, direct airway injury did not induce the formation of granulation tissue under the disrupted epithelium of airway mucosa in SCID mice 3 weeks after injury. CONCLUSION: The data indicate that the immune response that results in the formation of granulation tissue is mediated by circulating B- and/or T-cell processes rather than resident airway immune cells. Further studies focusing on cellular adaptive immune processes in response to airway injury may provide a novel treatment modality for subglottic stenosis.

Unusual fibrosclerotic lesion of the laryngotracheal complex presenting as subglottic stenosis.

We present a case report that describes the pathology, presentation, and management complexities of an unusual, destructive fibrosclerotic lesion of the laryngotracheal complex. An otherwise healthy 21-year-old man presented with a 1-year history of progressive shortness of breath and stridor. The initial examination revealed a 3-cm, grade III subglottic stenosis. Nodular fibrosis of the strap muscles, laryngotracheal cartilages, and trachea was evident. Biopsies revealed dense peritracheal desmoplastic reaction with focal erosion of cartilage. However, features diagnostic for relapsing polychondritis, desmoid tumor, or orbital pseudotumor were absent. The disease progressed to involve severe stenosis and thickening of the trachea and main stem bronchi. Surgical and medical management of this unusual fibrosclerotic lesion did not ameliorate the disease process, but a recent encouraging response to tamoxifen citrate has been observed with improvements in vocal fold motion and activity levels. Prognosis and management experience for this unknown pathologic entity are absent in the literature. In this case, diffuse disease progression occurred despite surgical and medical management, but has been halted by tamoxifen therapy. The prospect of a durable response and disease remission is unknown.

Supraglottic stenosis in localized Wegener granulomatosis.

We present what we believe is the first reported case of a patient with supraglottic stenosis secondary to Wegener granulomatosis. The diagnosis was unclear initially because the biopsy results were nonspecific, but a finding of an elevated cytoplasmic-pattern antineutrophil cytoplasmic antibody (c-ANCA) level established the diagnosis of localized supraglottic Wegener granulomatosis. Wegener granulomatosis is characterized by necrotizing vasculitis that is localized predominantly to the kidneys and the upper and lower airways. In the airways, subglottic involvement is well documented, but to the best of our knowledge, supraglottic stenosis has not previously been described. Localized forms of Wegener granulomatosis are characterized by limited disease that involves only the upper airway. The diagnosis in localized forms is complex because histology is diagnostic in only 50% of cases, and only 60% of patients have a positive c-ANCA level. We discuss the diagnostic criteria and management strategies for these localized forms.

Antiepiligrin cicatricial pemphigoid of the larynx successfully treated with a combination of tetracycline and niacinamide.

A case of antiepiligrin cicatricial pemphigoid that primarily involved the larynx and required a tracheostomy was studied. The diagnosis was based on the direct immunofluorescence findings of a biopsy specimen from the glottis, immunofluorescence using normal and 1M sodium chloride-split normal human skin as substrates, and immunoprecipitation. A dramatic clinical improvement was observed after the combined administration of tetracycline hydrochloride and niacinamide. The tracheal stoma could be shut after the narrow segment was cut by means of carbon dioxide laser therapy. The patient showed no respiratory difficulty during the 2-year follow-up period. The combined therapy of tetracycline and niacinamide is thus considered to be an effective treatment for various types of cicatricial pemphigoid.

Autoantibodies against constituents of neutrophils in the diagnosis and treatment of (isolated) subglottic stenosis.

Six patients had a subglottic stenosis either as a presenting symptom or as a manifestation of a systemic disease. All patients had in common the presence of circulating autoantibodies against constituents of neutrophils on indirect immunofluorescence. Cytoplasmic and perinuclear staining patterns were recognized. Such autoantibodies have been reported in Wegener's granulomatosis, microscopic polyarteritis, (idiopathic) glomerulonephritis, and Churg-Strauss syndrome. However, only one of the six patients fulfilled the criteria for these conditions. Because a positive test for autoantibodies against constituents of neutrophils is rare in other conditions and because other diseases had been excluded, we suggest that this places subglottic stenosis within the spectrum of necrotizing (granulomatous) vasculitis. The consequences for therapy are discussed.

Circulating anti-neutrophil cytoplasmic autoantibodies in subglottic stenosis: a useful aid in diagnosing vasculitis in this condition?

Five patients with subglottic stenosis, occurring either as a presenting symptom or as a manifestation in the course of a systemic disease, are described. Indirect immunofluorescence revealed the presence of circulating autoantibodies against both cytoplasmic and perinuclear constituents of neutrophils in all five. Antibodies directed against a 29 kDa antigen of the azurophilic granules (two patients), against myeloperoxidase (one patient), and against both the 29 kDa antigen and myeloperoxidase (one patient) were found by enzyme-linked immunosorbent assay. These autoantibodies have previously been found in patients with Wegener's granulomatosis, microscopic polyarteritis, (idiopathic) glomerulonephritis and Churg-Strauss syndrome. However, only one of these five patients fulfilled the criteria for these conditions. Since these autoantibodies are seldom observed in other conditions, and other diseases had been excluded by careful evaluation, we suggest that their presence places subglottic stenosis within the spectrum of necrotizing (granulomatous) vasculitis. Whether immunosuppressive therapy is always warranted in patients with subglottic stenosis and circulating anti-neutrophil cytoplasmic antibodies is a matter of debate.

[Indicators of immunologic reactivity in children with chronic laryngostenosis]. / Pokazateli immunologicheskoi reaktivnosti u detei s khronicheskimi stenozami gortani.

Immunological examinations of 40 children with papillomatosis and chronic cicatricial stenosis of the larynx included measurements of circulating immune complexes (CIC) and lysozyme in the saliva and serum as well as complement activity in serum. The examinations were performed regularly during treatment. It was found that immunobiological factors played an important part in the pathogenesis of papillomatosis and cicatricial stenosis of the larynx in children. It was shown that CIC and lysozyme concentrations in the saliva and serum as well as complement activity in serum increased. In the course of treatment all the groups displayed an increase of lysozyme in the saliva; patients with papillomatosis showed a decrease of the CIC concentration and those with cicatricial stenosis a decline of complement activity in serum. Involvement of the autoimmune component in the pathogenesis of the above diseases is discussed. Applicability of the results for controlling the therapeutic efficacy and predicting the outcome of diseases is considered.