Mapping Human Immunity and the Education of Waldeyer's Ring.

The development and deployment of single-cell genomic technologies have driven a resolution revolution in our understanding of the immune system, providing unprecedented insight into the diversity of immune cells present throughout the body and their function in health and disease. Waldeyer's ring is the collective name for the lymphoid tissue aggregations of the upper aerodigestive tract, comprising the palatine, pharyngeal (adenoids), lingual, and tubal tonsils. These tonsils are the first immune sentinels encountered by ingested and inhaled antigens and are responsible for mounting the first wave of adaptive immune response. An effective mucosal immune response is critical to neutralizing infection in the upper airway and preventing systemic spread, and dysfunctional immune responses can result in ear, nose, and throat pathologies. This review uses Waldeyer's ring to demonstrate how single-cell technologies are being applied to advance our understanding of the immune system and highlight directions for future research.

Topical administration of S. salivarius 24SMB-S. oralis 89a in children with adenoidal disease: a double-blind controlled trial.

Chronic adenoiditis (CA) is generally sustained by some infectious foci mainly located within the nasopharynx or in the deep adenoidal pads and it is characterized by a complex interplay between bacterial species. The aim of this study was to assess the efficacy and safety of the topical nasal administration of a probiotic compound based on S. salivarius 24SMB and S. oralis 89a in children with CA in terms of reduction in: the number of acute adenoidal infections (primary outcome), and in the blockage of the nasopharynx space by hypertrophic adenoids (secondary outcome). A prospective, double-blind, 1:1 randomized controlled study was performed to test the effectiveness of a 90-day treatment with Rinogermina spray (DMD ITALIA s.r.l, Rome), 1 puff each nostril twice a day for 90 days, to nasal spray placebo in children with CA (in terms of number of acute exacerbations and blockage of nasopharynx space assessed after 90 days of treatment- T1, and 90 days later- T2). The final analysis was based on 152 children (males = 48.0%; mean age = 49.2 ± 14.1 months). Compared to the baseline, no significant differences in terms of number of acute exacerbations at T1 and T2 follow-up visits were detected in both groups. After treatment, a significant reduction in the blockage of nasopharynx space by hypertrophic adenoids (0.002 < p-value < 0.007) compared to the baseline was attested in the study group at T1 and T2, but not in the control group. CONCLUSIONS: Our findings document a positive effect of Rinogermina spray in achieving reduction in the blockage of nasopharynx space by hypertrophic adenoids, thus suggesting that its use into the integrated therapeutic management of children with CA could be of a certain utility. WHAT IS KNOWN: • Chronic adenoiditis in children results from an imablance in baterial homeostasis at the nasophaynx, with impairment in respiratory microbiota. • The modulatory effect of target transnasal bacteriotheray by means of S. salivarius has been considered in children with chronic adenoiditis in children with recurrent acute otitis media with preliminary positive results. WHAT IS NEW: • This randomized controlled study, specifically designed on a cohrt of children with chronic adenoiditis, documents a certain effectiveness of the probiotic treatment in achieving a reduction in the grade of adenoidal hypertropy, compared to placebo.

Causal association of gastroesophageal reflux disease with chronic sinusitis and chronic disease of the tonsils and adenoids.

BACKGROUND: Exploring bidirectional causal associations between gastroesophageal reflux disease (GERD) and chronic disease of the tonsils and adenoids and chronic sinusitis, respectively. METHODS: We first conducted a TSMR (two-sample mendelian randomization) study using the results of the inverse variance weighting method as the primary basis and bidirectional MR to rule out reverse causation. Subsequently, MVMR (multivariate MR) analysis was performed to identify phenotypes associated with SNPs and to explore the independent effect of GERD on two outcomes. Finally, we calculated MR-Egger intercepts to assess horizontal polytropy and Cochran's Q statistic to assess heterogeneity and ensure the robustness of the study. RESULTS: For each standard deviation increase in genetically predicted GERD rate, there was an increased risk of chronic disease of the tonsils and adenoids (OR 1.162, 95% CI 1.036-1.304, P: 1.06E-02) and of developing chronic sinusitis (OR 1.365, 95% CI 1.185-1.572, P: 1.52E-05), and there was no reverse causality. Causality for TSMR was obtained on the basis of IVW (inverse variance weighting) and appeared to be reliable in almost all sensitivity analyses, whereas body mass index may be a potential mediator of causality between GERD and chronic sinusitis. CONCLUSION: There is a causal association between GERD and chronic disease of the tonsils and adenoids and chronic sinusitis, respectively, and the occurrence of GERD increases the risk of developing chronic disease of the tonsils and adenoids and chronic sinusitis.

Comparison of PAS and adenoids in patients with and without maxillary micrognathia before orthodontic treatment.

OBJECTIVE: Craniofacial anomalies are widely discussed as predisposing factors of breathing disorders. Since many more cofactors exist, this study investigated the association between maxillary micrognathia and morphological changes of posterior airway space and adenoids in these patients. MATERIAL AND METHODS: Cephalometric radiographs of n = 73 patients were used for data acquisition. The patients were divided into two groups according to certain skeletal characteristics: maxillary micrognathia (n = 34, 16 female, 18 male; mean age 10.55 ± 3.03 years; defined by a SNA angle < 79°) and maxillary eugnathia (n = 39, 19 female, 20 male; mean age 10.93 ± 3.26 years; defined by a SNA angle > 79°). The evaluation included established procedures for measurements of the maxilla, posterior airway space and adenoids. Statistics included Kolmogorov-Smirnov-, T- and Mann-Whitney-U-Tests for the radiographs. The level of significance was set at p < 0.05. RESULTS: The cephalometric analysis showed differences in the superior posterior face height and the depth of the posterior airway space at palatal level among the two groups. The depth of the posterior airway space at mandibular level was the same for both groups, just as the size of the area taken by adenoids in the nasopharynx. CONCLUSIONS: Skeletal anomalies affect the dimension of the posterior airway space. There were differences among the subjects with maxillary micrognathia and these with a normal maxilla. However, the maxilla was only assessed in the sagittal direction, not in the transverse. This study showed that the morphology of the maxilla relates to the posterior airway space whereas the adenoids seem not to be affected. CLINICAL RELEVANCE: Maxillary micrognathia is significantly associated with a smaller depth of the posterior airway space at the palatal level compared to patients with maxillary eugnathia.

[Pediatric chronic rhinosinusitis]. / Pädiatrische chronische Rhinosinusitis.

Pediatric chronic rhinosinusitis (PCRS) differs from adult chronic rhinosinusitis (CRS) in several aspects. The confrontation with the environment takes place in the growing sinus system, and the immune system is also developing. The inflammatory mechanisms differ to some extent from those of adult CRS patients. The adenoid vegetations play an important role, particularly during the first 6 years of life. Other pathogenetic aspects are important (e.g., asthma, gastroesophageal reflux disease, immunodeficiency). Genetically determined systemic diseases such as cystic fibrosis cause specific challenges in diagnostics and treatment already in childhood. Consistent conservative therapy is often successful, but surgical procedures that have been proven to be effective and associated with few complications are also increasingly used.

What are the Soft Tissue Risk Factors for Obstructive Sleep Apnea in Patients with Down's Syndrome?

OBJECTIVE: To determine the risk factors and their respective magnitudes for developing Obstructive Sleep Apnea (OSA) in Down syndrome (DS) patients. DESIGN: Retrospective cohort study. PATIENTS: The 2016 Kids' Inpatient Database (KID) was queried to identify all patients diagnosed with DS. MAIN OUTCOME MEASURES: The primary predictor variables were tonsillar hypertrophy (TH), adenoidal hypertrophy (AH), Hypertrophy of Tonsils & Adenoids (HTA), Laryngeal Stenosis (LS), Hypotonia, Glossoptosis, Congenital Laryngomalacia (CL), and Overweight & Obesity (OO). The primary outcome variable was OSA. RESULTS: The final sample consisted of 18,181 patients with a diagnosis of DS. Relative to patients aged 0-5, patients aged 6-10 (OR 3.5, P < 0.01), 11-5 (OR 3.4, P < 0.01), and 16 & above (OR 3.6, P < 0.01) were each independently associated with increased odds of OSA. Further, TH (OR 23.2, P < 0.01), AH (OR 20.3, P < 0.01), HTA (OR 64.2, P < 0.01), glossoptosis (OR 5.0, P < 0.01), CL (OR 4.3, P < 0.01), and OO (OR 3.7, P < 0.01) were all independent risk factors for OSA. CONCLUSIONS: The presence of hypertrophied tonsils and adenoids together was the strongest risk factor for OSA. DS patients aged six and above were at risk for OSA development relative to younger patients. Patients with DS should be tested for OSA, which otherwise will deteriorate their existing comorbidities.

[Adenoids-diagnosis and treatment: the new German S2k guideline]. / Adenoide Vegetationen ­ Diagnostik und Therapie ­ die neue S2k-Leitlinie.

Hyperplasia of the pharyngeal tonsils is to be considered pathologic when nasopharyngeal symptoms of mechanical obstruction and/or chronic inflammation occur. Chronic Eustachian tube dysfunction can result in various middle ear diseases such as conductive hearing loss, cholesteatoma, and recurrent acute otitis media. During examination, attention should be paid to the presence of adenoid facies (long face syndrome), with a permanently open mouth and visible tip of the tongue. In the case of severe symptoms and/or failure of conservative treatment, adenoidectomy is usually performed on an outpatient basis. Conventional curettage remains the established standard treatment in Germany. Histologic evaluation is indicated for clinical evidence of mucopolysaccharidoses. Due to the risk of hemorrhage, the preoperative bleeding questionnaire, which is obligatory before every pediatric surgery, is referred to. Recurrence of adenoids is possible despite correct adenoidectomy. Before discharge home, otorhinolaryngologic inspection of the nasopharynx for secondary bleeding should be performed and anesthesiologic clearance obtained.

Adenoid hypertrophy-​diagnosis and treatment: the new S2k guideline.

Hyperplasia of the pharyngeal tonsils is to be considered pathologic when nasopharyngeal symptoms of mechanical obstruction and/or chronic inflammation occur. Chronic Eustachian tube dysfunction can result in various middle ear diseases such as conductive hearing loss, cholesteatoma, and recurrent acute otitis media. During examination, attention should be paid to the presence of adenoid facies (long face syndrome), with a permanently open mouth and visible tip of the tongue. In the case of severe symptoms and/or failure of conservative treatment, adenoidectomy is usually performed on an outpatient basis. Conventional curettage remains the established standard treatment in Germany. Histologic evaluation is indicated for clinical evidence of mucopolysaccharidoses. Due to the risk of hemorrhage, the preoperative bleeding questionnaire, which is obligatory before every pediatric surgery, is referred to. Recurrence of adenoids is possible despite correct adenoidectomy. Before discharge home, otorhinolaryngologic inspection of the nasopharynx for secondary bleeding should be performed and anesthesiologic clearance obtained.

Characteristics of the bacterial microbiota in the upper respiratory tract of children.

PURPOSE: The respiratory tract microbiota are deemed as the gatekeeper to health. Consequently, microbiota dysbiosis can lead to the development of diseases. To identify the exact origins of the localized pathogenic bacteria, we investigated bacterial composition in the upper airway tract. METHODS: Separate mucosal swabs were collected from nostril or oropharynx of each participant. Meanwhile, the lymphoid tissues including adenoids and tonsils were collected during operation. DNAs were exacted from all the samples for the following 16S rRNA analysis. RESULTS: At the phylum level, the basic bacterial structures in the adenoids, tonsils, oropharynx, and nostrils were generally similar: five main phyla Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria form the majority of the microbiota. However, across these four sites, the microbiota composition differed. More specifically, the bacterial composition in the nostrils was unique. There, Firmicutes and Actinobacteria were the most abundant phyla, while Bacteroides and Fusobacteria were the least abundant. At the genus level, Staphylococcus, Dolosigranulum, Corynebacterium, and Moraxella were the most plentiful, while Fusobacteria was the least ample. Across all sites, Streptococcus displayed similar abundances. Fusobacteria exhibited higher abundances in the lymphoid tissues and oropharynx. Haemophilus and Neisseria were more plentiful in the tonsils and oropharynx. Notably, Klebsiella, which is normally localized to the gut, was abundant in the adenoids and tonsils. CONCLUSION: Our data indicate that promising pathogenic bacteria originate from all sites in the upper airway. The upper tract lymphoid tissues, normally considered as immune organs, may also serve as reservoirs for pathogenic bacteria.

Adenoidectomy for middle ear disease in cleft palate children: a systematic review.

PURPOSE: Cleft palate children have a higher incidence of otitis media with effusion, more frequent recurrent acute otitis media episodes, and worse conductive hearing losses than non-cleft children. Nevertheless, data on adenoidectomy for middle ear disease in this patient group are scarce, since many feared worsening of velopharyngeal insufficiency after the procedure. This review aims at collecting the available evidence on this subject, to frame possible further areas of research and interventions. METHODS: A PRISMA-compliant systematic review was performed. Multiple databases were searched with criteria designed to include all studies focusing on the role of adenoidectomy in treating middle ear disease in cleft palate children. After duplicate removal, abstract and full-text selection, and quality assessment, we reviewed eligible articles for clinical indications and outcomes. RESULTS: Among 321 unique citations, 3 studies published between 1964 and 1972 (2 case series and a retrospective cohort study) were deemed eligible, with 136 treated patients. The outcomes were positive in all three articles in terms of conductive hearing loss improvement, recurrent otitis media episodes reduction, and effusive otitis media resolution. CONCLUSION: Despite promising results, research on adenoidectomy in treating middle ear disease in the cleft population has stopped in the mid-Seventies. No data are, therefore, available on the role of modern conservative adenoidectomy techniques (endoscopic and/or partial) in this context. Prospective studies are required to define the role of adenoidectomy in cleft children, most interestingly in specific subgroups such as patients requiring re-tympanostomy, given their known risk of otologic sequelae.

An Overview of Adenoid Microbiome Using 16S rRNA Gene Sequencing-Based Metagenomic Analysis.

Background and Objectives: the upper respiratory tract harbors the highest bacterial density in the whole respiratory system. Adenoids, which are located in the nasopharynx, are a major site of bacterial colonies in the upper airways. Our goal was to use culture-independent molecular techniques to identify the breadth of bacterial diversity in the adenoid vegetations of children suffering from chronic rhinosinusitis and obstructive sleep apnea. Materials and methods: in total, 21 adenoid samples were investigated using amplification and sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene. Results: among the most common bacterial species found were Veillonella atypica, Fusobactrium nucelatum, Shaalia odontolytica, and Moraxella catarrhalis. Veillonella atypica and Fusbacteriumnucelatum dominated the microbiome in all 21 samples, attributing to more than 60% of all detected genetic material. Conclusions: since both Veillonella atypica and Fusobacterium nucleatum are, predominantly, oral cavity and dental microorganisms, our findings may suggest oral microbiome migration deeper into the oropharynx and nasopharynx where these bacteria colonize adenoid vegetations.

[Diagnosis and correction of the obstructive sleep apnea syndrome in children with tonsillar ring pathological conditions]. / Diagnostika i korrektsiya sindroma obstruktivnogo apnoe sna u detei s patologiei limfoglotochnogo kol'tsa.

OBJECTIVE: To summarize the results of a study of the clinical and polygrapic features of sleep in children with pathologic conditions of the tonsillar ring and obstructive sleep apnea. Tonsillar hypertrophy is the most common cause of obstructive sleep apnea in children. Using the data of overnight polysomnographic study and/or nocturnal pulse oximetry, groups of patients were distinguished depending on the presence and severity of their sleep breathing disorders. The effectiveness of adenotomy, adenotonsillotomy and/or adenotonsillectomy in children is demonstrated, depending on the severity of obstructive sleep apnea syndrome. Evaluation of breathing in sleeping children by polygraphic methods is necessary for early detection of obstructive sleep apnea syndrome and monitoring the effectiveness of surgical treatment.

Hypoxia induced factor-1α levels in patients undergoing adenoidectomy.

Among  the most common causes of nasal congestion in childhood is adenoid hypertrophy (AH) which leads to hypoxia. In this study, we studied plasma concentrations of hypoxia induced factor-1α (HIF-1α) in children undergoing adenoidectomy. The study included a total of 86 participants: 39 patients with AH and 47 healthy individuals. Serum HIF-1α levels (ng/mL) were measured by ELISA. HIF-1α concentrations were compared to the adenoid-nasopharyngeal ratio (ANR) of patients with AH, as recorded in the medical records. We found significantly higher concentrations of HIF-1α (0.30 ± 0.47 ng/mL) in patients with AH as compared to healthy controls (0.24 ± 0.07 ng/mL, p = .011). HIF-1α levels were not significantly different regarding gender between patients with AH (p = .77) and in the control group (p = .97). In patients with AH, there was a moderately significant positive correlation between HIF-1α levels and Hb (p = .000), (correlation coefficient r = 0.542). There was a positive correlation between HIF-1α and ANR in patients with AH (p = .005, r = 0.439). This study indicates that AH increases HIF-1α levels. We also observed a moderately significant positive correlation between HIF-1α and ANR in patients with AH. HIF-1α levels are a potential biomarker for hypoxia in patients with AH.

Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms.

BACKGROUND: Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN) ratios. METHODS: This retrospective study included thirty-five patients aged 9-15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio ≥ 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (ΔP), maximum midsagittal velocity (Vms), maximum wall shear stress (Pws), and minimum wall static pressure (Pw). RESULTS: The maximum Vms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as ΔP, the maximum Pws, and minimum Pw, no significant difference is found between the two groups. CONCLUSIONS: The maximum Vms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum Vms, which could assist clinicians in estimating the airflow features in the UA.

Snoring toddlers with and without obstructive sleep apnoea differed with regard to snoring time, adenoid size and mouth breathing.

AIM: The difficulty of assessing the likelihood of obstructive sleep apnoea (OSA) in children who snore without full-night polysomnography is widely recognised. Our aim was to identify features that were characteristic of two-year-old children with OSA and evaluate whether this information could be used to assess the likelihood of OSA. METHODS: The study was carried out as part of the Child-Sleep Project, a longitudinal birth cohort study of children born at Tampere University Hospital, Finland. This part of the study focused on the children in the cohort who snored and was carried out between 2013 and 2015. The primary outcomes were measured using parental questionnaires, polysomnography and clinical examinations. RESULTS: In total, 52 children participated at a mean age of 27 months (range 23-34). Of these, 32 (44% male) snorers and 20 (70% male) controls. The most significant findings were that children who had OSA demonstrated longer snoring time (P = .003), a greater tendency for mouth breathing (P = .007) and bigger adenoid size (P = .008) than snorers without OSA. CONCLUSION: Snoring time, adenoid tissue size and mouth breathing were important features that identified the likelihood of OSA in snoring toddlers.

Relating three-dimensional airway measurements to the apnea-hypopnea index in pediatric sleep apnea patients.

OBJECTIVES: (a) To evaluate three-dimensional radiographic airway analysis as it relates to the pre-test probability for sleep apnea in pediatric patients, and (b) to develop cut-off values for measurements showing promising results. SETTING AND SAMPLE POPULATION: A consecutive series of pediatric patients between the ages of 7 and 17 years, referred for a sleep study were recruited. Cone beam computed tomography (CBCT) scans were acquired for 103 subjects within one month following the sleep study. METHODS: Three-dimensional airway analysis was performed including volumetric, area and linear measurements. Correlations with the apnea-hypopnea index (AHI) and receiver operating characteristic (ROC) curves were constructed. Sensitivity and specificity were calculated for prediction of AHI ≥ 5 and AHI ≥ 10. RESULTS: 99 CBCT scans were included (median age = 11 years). The nasopharyngeal volume (NPV) significantly correlated with AHI (rho≈-0.4, P < .05). In subjects aged 7-11 years, proposed cut-off values for NPV are 2400mm3 and 1600mm3 for AHI ≥ 5 and AHI ≥ 10, respectively. In subjects aged 12-17 years, proposed cut-off values for NPV are 3500mm3 and 2700mm3 for AHI ≥ 5 and AHI ≥ 10, respectively. Oropharyngeal cross-sectional area (OCSA) demonstrated significant predictive value in ROC curve analysis, and cut-off values for this airway measure are also proposed. CONCLUSIONS: Contrary to findings in adults, the NPV shows promise when screening for sleep apnea in children when CBCT scans are available. The OCSA might also be of value when screening for sleep apnea especially in older children.

Looking for a cutoff value for the decongestant test in children suffering with turbinate hypertrophy.

OBJECTIVE: The main causes for objectively confirmed chronic impaired nasal breathing in children are adenoid and turbinate hypertrophy. Turbinate hypertrophy may be addressed by turbinate surgery. However, specialized guidelines include no specific indications for pediatric patients. The decongestant test consists of simulating the effect of turbinate surgery by means of a nasal decongestant. This project, developed by the YO-IFOS rhinology group, aims to establish a cutoff value for the nasal decongestant test with rhinomanometry to select children for turbinate surgery. METHODS: Children between 4 and 15 years of age were included. Cases were consecutively selected from children affected by turbinate hypertrophy undergoing turbinate radiofrequency ablation with or without adenoidectomy. Controls were consecutively selected from a sample of healthy children. All the subjects were examined with anterior active rhinomanometry with and without nasal decongestant. RESULTS: Sample included 72 cases and 24 healthy controls. There was a statistically significant difference in the improvement with the decongestant between cases (57.91%) and controls (15.67%). The ROC curve revealed an area under the curve of 0.97. The highest amount of correctly classified individuals (93.44%) corresponded to the cutoff value of 31.66%. However, the value with the highest specificity and highest Youden's index was the 38.88% improvement in nasal resistance with nasal decongestant. CONCLUSIONS: In conclusion, a preliminary cutoff value for the decongestant test used with rhinomanometry in children has been established. This test could help identify children for turbinate surgery.

[Expression of terminal deoxynucleotidyl transferase in the pharyngeal and palatine tonsils in local infectious and inflammatory diseases of the upper respiratory tract and pharynx in childhood]. / Ekspressiya terminal'noi dezoksinukleotidiltransferazy v glotochnoi i nebnykh mindalinakh pri mestnykh infektsionno-vospalitel'nykh zabolevaniyakh verkhnikh dykhatel'nykh putei i glotki v detskom vozraste.

Along with central immune organs, the peripheral lymphoepithelial organs of the pharynx are actively involved in protecting the body from infections. Adaptive, or induced, immunity occurs during the postnatal ontogenesis of immunocompetent lymphocytes, which includes the secondary somatic recombination of the V genes with the participation of recombination-activating gene (RAG) and terminal deoxynucleotidyl transferase (Tdt) proteins. This publication discusses the results of detection of Tdt-positive cells in the pharyngeal and palatine tonsils of children of different ages, who had been operated on for adenoid vegetations and chronic tonsillitis. Attention is drawn to the localization of Tdt+ cells, the level of Tdt expression, an attempt to clarify the phenotype, destination, and place in the diagnostic arrays of functional markers when an adaptive immunity is generated in children.

Mycobacterium leprae on Palatine Tonsils and Adenoids of Asymptomatic Patients, Brazil.

We investigated palatine tonsil and adenoid specimens excised from otorhinolaryngological patients in a leprosy-endemic region of Brazil. Fite-Faraco staining identified Mycobacterium spp. in 9 of 397 specimen blocks. Immunohistochemistry and molecular analysis confirmed the presence of Mycobacterium leprae, indicating that these organs can house M. leprae in persons inhabiting a leprosy-endemic region.

IL-17C expression and its correlation with pediatric adenoids: a preliminary study.

Objective: Interleukin-17 (IL-17) C is a cytokine expressed by epithelial cells in response to bacterial stimulation. In contrast to other members of the IL-17 family of cytokines, IL-17C is upregulated early during infection, maintains integrity of the epithelial layer barrier, and mediates the innate immune response. We investigated the expression profile of IL-17C in pediatric adenoids. Methods: Pediatric adenoid tissues and lavage fluids were collected from a total of 38 subjects. The Limulus amebocyte lysate test and real-time PCR using Staphylococcus aureus primers were performed to evaluate bacterial contents in adenoids. Expression of IL-17RE in adenoids was analyzed using real-time polymerase chain reaction and western blot. The expression of IL-17C was evaluated by western blot and immunohistochemistry and compared between allergic rhinitis (AR) and control subjects. The levels of Hsp27, Hsp70, and IL-17C in adenoid lavage fluids were evaluated by enzyme-linked immunosorbent assay, and the correlation between these molecules was statistically analyzed. Results: The pediatric adenoids were found to be exposed to bacteria and had a normal flora comprising both gram-negative and -positive bacteria. IL-17RE, an IL-17C specific receptor, was highly expressed in the epithelium of adenoids. IL-17C was expressed in all evaluated adenoid tissue samples, irrespective of the allergic status of the patient. IL-17C secretion was detected in half of the adenoid lavage fluid samples and was associated with Hsp70 level. Conclusion: Our findings indicate the possible role of pediatric adenoids in innate immunity modulation via an innate immunity-associated cytokine.