A Tissue Engineered 3D Model of Cancer Cell Invasion for Human Head and Neck Squamous-Cell Carcinoma.

Head and neck squamous-cell carcinoma (HNSCC) is associated with aggressive local invasiveness, being a main reason for its poor prognosis. The exact mechanisms underlying the strong invasive abilities of HNSCC remain to be elucidated. Therefore, there is a need for in vitro models to study the interplay between cancer cells and normal adjacent tissue at the invasive tumor front. To generate oral mucosa tissue models (OMM), primary keratinocytes and fibroblasts from human oral mucosa were isolated and seeded onto a biological scaffold derived from porcine small intestinal submucosa with preserved mucosa. Thereafter, we tested different methods (single tumor cells, tumor cell spots, spheroids) to integrate the human cancer cell line FaDu to generate an invasive three-dimensional model of HNSCC. All models were subjected to morphological analysis by histology and immunohistochemistry. We successfully built OMM tissue models with high in vivo-in vitro correlation. The integration of FaDu cell spots and spheroids into the OMM failed. However, with the integration of single FaDu cells into the OMM, invasive tumor cell clusters developed. Between segments of regular epithelial differentiation of the OMM, these clusters showed a basal membrane penetration and lamina propria infiltration. Primary human fibroblasts and keratinocytes seeded onto a porcine carrier structure are suitable to build an OMM. The HNSCC model with integrated FaDu cells could enable subsequent investigations into cancer cell invasiveness.

[Increasing incidence of mastoidectomies in children : Result of reduced antibiotic therapy or late COVID-19 sequela?] / Steigende Inzidenzen bei Mastoidektomien im Kindesalter : Folge geringeren Antibiotikaeinsatzes oder eine COVID-19-Spätfolge?

BACKGROUND: An increasing number of pediatric patients with mastoiditis and a consequent increase in mastoidectomy rates was noted in 2022 and 2023. OBJECTIVE: This study aimed to analyze the increase in the number of children presenting with mastoiditis and subsequent mastoidectomy, to assess correlations with prior antibiotic treatment or COVID-19 infection, and to provide an overview of involved pathogens, treatment, and disease course. MATERIALS AND METHODS: A retrospective analysis of all patients with mastoidectomy since 2012 was conducted. Data collected comprised type and duration symptoms, prior antibiotic therapy, diagnostic tests and disease course, causal pathogens, length of hospitalization, and complications. RESULTS: A highly significant increase in mastoidectomies in children could be demonstrated from 2022. Neither the pathogens involved nor the course of disease or complications showed differences. An increase in the number of patients with prior outpatient antibiotic therapy could be shown. About a half of the patients becoming ill after fall 2022 had a positive history of COVID. Hyperplasia of adenoid tissue was a far less frequent causal mechanism than in the years before COVID. CONCLUSION: No clear correlation with reduced outpatient antibiotic therapy could be found. Whether there exists an association with prior COVID infection cannot be judged at this time, due to the high number of asymptomatic and therefore unknown COVID infections.

[Repetitio est mater studiorum-implementation of ENT cases in case-based e-learning]. / Repetitio est mater studiorum ­ Implementierung von HNO-Fällen in fallbasiertes E-Learning.

BACKGROUND: German university otorhinolaryngology has a need for digital teaching content. Case-based e­learning represents a digital teaching methodology. The data on student use of case-based e­learning in university teaching of ENT medicine are limited. OBJECTIVE: The aim of this work was to determine the extent to which voluntary case-based e­learning is used by otolaryngology students and what influence the quality of the e­learning has on motivation to use e­learning and on the interest in otolaryngology. MATERIALS AND METHODS: Fifteen voluntary e­learning cases were created based on the content of the ENT lecture in the winter semester 2022/2023. Subsequently, a descriptive evaluation of the usage statistics of the cases of 157 students was conducted. Likewise, an evaluation of the quality of the e­learning as well as the motivation to complete it and the interest in otorhinolaryngology was carried out using a voluntary questionnaire. RESULTS: Voluntary case-based e­learning was used to varying degrees by 66% of the students. The quality of e­learning correlated significantly with the motivation and the interest in otolaryngology. CONCLUSION: The teaching content of otorhinolaryngology can be implemented sufficiently in case-based e­learning and is characterized by satisfactory student acceptance. Integration should be accomplished in a high-quality manner to increase motivation and interest in otorhinolaryngology.

Do Disinfectant Solutions during Gargling Reach the Pharynx?

INTRODUCTION: In times of COVID-19, gargling disinfectant is commonly used. Disinfectant solutions seem to decrease the infection's symptoms. For disinfection, several techniques are reported. So far, there are no data about the regions in the upper airways achieved by gargled fluid. METHODS: Ten healthy volunteers without any dysphagia were investigated with a high-sensitivity flexible endoscopic evaluation of swallowing (hsFEES®) during and after gargling colored water. One volunteer repeated the gargling process in fast and real-time MRI. RESULTS: In all cases, no color accumulation was detected on the posterior pharyngeal wall, epi- or hypopharynx during gargling. The MRI scans confirmed the results. CONCLUSIONS: hsFEES® and fast MRI provide an insight into the gargling pattern. Data show that during gargling, the fluid covers the soft tissue in the oral cavity and the anterior part of the soft palate, but not the posterior pharyngeal wall nor the epi- and hypopharynx.

[Diagnosis and therapy of sinonasal mucosal melanoma]. / Diagnostik und Therapie von Schleimhautmelanomen der Nase/Nasennebenhöhlen.

Sinonasal mucosal melanoma (SNMM) is a rare and aggressive disease representing only 4% of all sinonasal malignancies and 1.4% of all melanomas. With an incidence of approximately 0.2 to 2 cases per million, the disease represents a very rare cancer type. As a result, there is a lack of data and most of the evidence for this highly aggressive disease is based on retrospective observations and analyses. The standard of care is radical tumor resection followed by an adjuvant radiotherapy. Nevertheless, the rate of local recurrence is high, up to 50%. In addition, the majority of patients (up to 70%) develop distant metastases during the course of their disease. Both contribute to the extremely poor prognosis of the disease. Mucosal melanomas (SM) and cutaneous melanomas (CM) behave differently with respect to biology, clinic presentation and prognosis. Compared to CM, survival rates are significantly lower for SM. The 5-year survival rate is around 25% in SNMM but 39-97% in cutaneous melanoma. Similar to CM, immune checkpoint inhibitors achieve promising results in SM. However, response rates are lower in SM compared to CM. The goal of this CME article is to provide an overview on biology, diagnosis, therapy, and prognosis of SNMM.

Aspergillus fumigatus-Specific T Cells in Patients with Chronic Rhinosinusitis.

INTRODUCTION: Aspergillus fumigatus belongs to the saprophytic fungi, and its spores form a significant part of the daily load of fungal spores inhaled as particles in aerosols. A. fumigatus is a possible T-cell activator. Its contribution to the pathogenesis of chronic rhinosinusitis (CRS) is controversially discussed. The aim of this study was to detect and characterize A. fumigatus-specific CD4+ and CD8+ T cells in patients with CRS with (CRSwNP) and without (CRSsNP) nasal polyps. METHODS: Tissue and blood samples were collected from patients who underwent paranasal sinus surgery due to CRSwNP or CRSsNP. Afterward, purified CD4+ and CD8+ cells were cultured together with antigen-presenting cells. A peptide mix derived from A. fumigatus antigen was added to the cultures. After 6 days, multicolor flow cytometry was performed, and proliferation was measured using the marker Ki-67. Cytokine secretion was quantified from the supernatant of the cell culture. RESULTS: Significant differences in the proliferation of nasal CD4+ T cells to A. fumigatus antigen were observed for cells from patients with CRSwNP in comparison to CRSsNP, while no differences were found between nasal and peripheral blood T cells. The activation of tissue-derived CD4+ T cells was associated with significantly higher concentrations of IL-4, IL-5, and IL-17a in the cell culture from patients with CRSwNP in comparison to CRSsNP and/or healthy controls. CONCLUSION: Our findings indicate that patients with CRSwNP harbor a higher proportion of A. fumigatus-reactive CD4+ T cells in the nasal mucosa than patients with CRSsNP. A. fumigatus-reactive CD4+ T cells of CRSwNP patients secreted TH2 cytokines and IL-17. Our findings suggest a role for A. fumigatus in the pathogenesis of CRSwNP and provide a rationale for targeted therapies.

Influence of Wound Fluid on the Transdifferentiation of Human Mesenchymal Bone Marrow Stem Cells into Cancer-Associated Fibroblasts.

Cancer-associated fibroblasts (CAF) in the tumor microenvironment have a decisive influence on tumor growth and metastatic behavior. The cellular origins as well as the stimuli leading to CAF formation are heterogenous, impeding a precise characterization. Aim of this study was to analyze the influence of cytokines secreted in the process of wound healing, tumor cell-associated paracrine-secreted factors, and direct cell-cell contact on the expression of the CAF-associated markers fibroblast activation protein (FAP), α-smooth muscle actin (α-SMA), thrombospondin-1 (THBS1), and tenascin-c (TNC) by RT-PCR in mesenchymal stem cells (MSC). Cells developed different morphological characteristics after incubation with wound fluid (WF). Moreover, expression of FAP and α-SMA in MSC was significantly reduced after WF compared to tumor-conditioned medium and in co-culture with tumor cells; THBS1 and TNC were not significantly altered after any of the different incubation methods. There were no alterations of expression patterns of FAP and α-SMA in the immunohistochemical analysis. Differ-ences in the cytokine composition of the media were found in the dot blot. The heterogeneity of the results emphasizes the complexity of the interactions of tumor cells and cells of the microenvironment, particularly through the addition of human-derived WF.

Surgical management of lateral neck abscesses in children: a retrospective analysis of 100 cases.

Cervical abscesses are relatively common infections in pediatric patients. There is an ongoing debate about the necessity and time point of surgical drainage. The identification of a focus of infection might play an important role in facilitating a therapeutic decision. In a retrospective study, 100 pediatric patients aged 1-18 years who underwent incision and drainage of a lateral cervical abscess at our institution were analyzed. Patients were divided into two groups based on whether a focus of infection could be identified or not. Data collection included patient characteristics, microbiological results, antibiotic regimen, and clinical course. A focus of infection was found in 29% (29/100) of the patients, most frequently in the tonsils. A causative microorganism was found in 75% (75/100) of all patients, with Staphylococcus aureus and Streptococcus pyogenes being the most common pathogens. All patients received an empiric antibiotic therapy in addition to surgery. Antibiotic medication was changed in 31% in both groups (9/29 with a focus of infection and 22/71 without a focus of infection) during therapy. Children without an identified focus of infection generally were younger and had more comorbidities reducing immune response while also showing differences in the pathogens involved. There were no complications associated to surgery or antibiotic therapy in any of the patients involved. CONCLUSION: Children with an identified focus of infection show several differences compared to those with isolated lateral abscesses, especially regarding the microorganisms involved. But the focus of infection seems not to have an impact on patient's outcome. WHAT IS KNOWN: • Neck abscesses are a relatively common disease in the pediatric population and may cause serious complications. • Therapy in general consists of intravenous antibiotics with or without surgery. WHAT IS NEW: • The focus identification has no impact on patient's outcome. • Children with an identified focus of infection show several differences compared to those with isolated lateral abscesses, especially regarding their medical history, age, and the microorganisms involved.

Multimodal treatment and immune checkpoint inhibition in sinonasal mucosal melanoma: real-world data of a retrospective, single-center study.

PURPOSE: Local failure and distant metastases occur frequently in sinonasal mucosal melanoma (SNMM). Response rates to chemotherapy are low and targetable mutations are rarely detected. However, there is increasing data indicating efficacy of immune checkpoint inhibition (ICI). The aim of this retrospective monocenter study was to assess the mutational landscape and to evaluate the outcome of surgical treatment and ICI in SNMM in a real-world setting. METHODS: Thirty-eight SNMM patients being treated between 1999 and 2020 at our institution were retrospectively reviewed. Survival curves were generated according to Kaplan-Meier and compared by the log-rank test. RESULTS: Local failure was seen in 60% of patients treated in a curative intent. Overall, 24% of all patients suffered from regional and 66% from distant metastases. Next generation sequencing revealed mutations of BRAF, NRAS and KRAS. One out of three patients treated with a primary ICI showed a complete response (CR) and two showed progressive disease. Eleven patients received ICI as a palliative treatment. CR could be observed in three patients and stable disease in one patient. In the whole study population, the 5-year overall survival rate (OS) was 26%. OS was better for patients who received ICI during the course of disease. CONCLUSIONS: Recurrences and distant metastases are frequent in SNMM. Durable CR could be observed after primary and palliative ICI. Therefore, ICI in a palliative, adjuvant or even neoadjuvant setting might play a promising role in SNMM therapy while targetable mutations are rarely detected.

[COVID-19: Collateral damage in head and neck oncology and preventive measures for future pandemics]. / COVID-19: Kollateralschäden in der Kopf-Hals-Onkologie und Präventivmaßnahmen für künftige Pandemien.

The start of the COVID-19 pandemic led to enormous challenges for global healthcare, as capacities and resources had to be made available quickly for the treatment of COVID-19 patients. As a result, restrictions had to be accepted, especially in the care of oncological patients. The collateral damage of these limitations inevitably also affects patients with head and neck cancer. This review article summarizes the development of tumor incidences during the pandemic, internationally developed guidelines for the care of patients with head and neck cancer and studies on the delay in oncological therapies and mortality. In addition, the effects on the mental health of the patients, the psychosocial consequences and ethical issues are examined. In perspective, preventive measures for such negative collateral effects in future pandemics are discussed using the example of a concept for application software (app)-based digital care for patients with head and neck cancer.

Deep neck infections with and without mediastinal involvement: treatment and outcome in 218 patients.

PURPOSE: Infections of the deep neck, although becoming scarcer due to the widespread use of antibiotics, still represent a dangerous and possibly deadly disease, especially when descending into the mediastinum. Due to the different specialities involved in the treatment and the heterogenous presentation of the disease, therapeutic standard is still controversial. This study analyzes treatment and outcome in these patients based on a large retrospective review and proposes a therapeutic algorithm. METHODS: The cases of 218 adult patients treated with deep neck abscesses over a 10-year period at a tertiary university hospital were analyzed retrospectively. Clinical, radiological, microbiological and laboratory findings were compared between patients with and without mediastinal involvement. RESULTS: Forty-five patients (20.64%) presented with abscess formation descending into the mediastinum. Those patients had significantly (all items p < 0.0001) higher rates of surgical interventions (4.27 vs. 1.11) and tracheotomies (82% vs. 3.4%), higher markers of inflammation (CRP 26.09 vs. 10.41 mg/dl), required more CT-scans (3.58 vs. 0.85), longer hospitalization (39.78 vs 9.79 days) and more frequently needed a change in antibiotic therapy (44.44% vs. 6.40%). Multi-resistant pathogens were found in 6.67% vs. 1.16%. Overall mortality rate was low with 1.83%. CONCLUSION: Despite of the high percentage of mediastinal involvement in the present patient collective, the proposed therapeutic algorithm resulted in a low mortality rate. Frequent CT-scans, regular planned surgical revisions with local drainage and lavage, as well as an early tracheotomy seem to be most beneficial regarding the outcome.

Surgical management of tympanojugular paragangliomas using the flexible CO2 laser.

PURPOSE: Surgery is a standard therapy for tympanojugular paragangliomas (TJP). Maintaining the quality of life (QoL) requires functional preservation. The flexible CO2 laser allows contact-free tumor removal. This retrospective study compares the postoperative functional outcomes of TJP surgery with and without the flexible CO2 laser. METHODS: Between 2005 and 2019, 51 patients with TJP were surgically treated at a tertiary hospital. Until 2012, 17 patients received conventional surgery. Thereafter, the flexible laser was used in 34 patients. Tumor extend, pre- and postoperative cranial nerve function, and complications were compared between the groups. RESULTS: The cohort consisted of 33 class A and B tumors and 18 class C and D tumors. Preoperative embolization was performed in 17 cases. Class C/D TJP were usually removed via an infratemporal fossa type A approach. Gross total tumor removal was achieved in 14/18 class C/D tumors. 3/51 patients suffered from long-term partial or complete facial palsy. No differences in post-therapeutic cranial nerve function or complications were noted between the conventional and laser group. One recurrence was observed after complete tumor resection. CONCLUSION: The flexible CO2 laser was shown to be a safe and effective alternative to conventional bipolar cauterization, which is appreciated by the surgeon in these highly vascularized tumors. Both techniques allowed a high tumor control rate and good long-term results also from a functional point of view.

Cultivation of Head and Neck Squamous Cell Carcinoma Cells with Wound Fluid Leads to Cisplatin Resistance via Epithelial-Mesenchymal Transition Induction.

Locoregional recurrence is a major reason for therapy failure after surgical resection of head and neck squamous cell carcinoma (HNSCC). The physiological process of postoperative wound healing could potentially support the proliferation of remaining tumor cells. The aim of this study was to evaluate the influence of wound fluid (WF) on the cell cycle distribution and a potential induction of epithelial-mesenchymal transition (EMT). To verify this hypothesis, we incubated FaDu and HLaC78 cells with postoperative WF from patients after neck dissection. Cell viability in dependence of WF concentration and cisplatin was measured by flow cytometry. Cell cycle analysis was performed by flow cytometry and EMT-marker expression by rtPCR. WF showed high concentrations of interleukin (IL)-6, IL-8, IL-10, CCL2, MCP-1, EGF, angiogenin, and leptin. The cultivation of tumor cells with WF resulted in a significant increase in cell proliferation without affecting the cell cycle. In addition, there was a significant enhancement of the mesenchymal markers Snail 2 and vimentin, while the expression of the epithelial marker E-cadherin was significantly decreased. After cisplatin treatment, tumor cells incubated with WF showed a significantly higher resistance compared with the control group. The effect of cisplatin-resistance was dependent on the WF concentration. In summary, proinflammatory cytokines are predominantly found in WF. Furthermore, the results suggest that EMT can be induced by WF, which could be a possible mechanism for cisplatin resistance.

Rare Diseases of Larynx, Trachea and Thyroid. / Seltene Erkrankungen des Larynx, der Trachea und der Schilddrüse.

This review article covers data on rare diseases of the larynx, the trachea and the thyroid. In particular, congenital malformations, rare manifestations of inflammatory laryngeal disorders, benign and malignant epithelial as well as non-epithelial tumors, laryngeal and tracheal manifestations of general diseases and, finally, thyroid disorders are discussed. The individual chapters contain an overview of the data situation in the literature, the clinical appearance of each disorder, important key points for diagnosis and therapy and a statement on the prognosis of the disease. Finally, the authors indicate on study registers and self-help groups.

[Primary Ciliary Dyskinesia - Interdisciplinary Diagnostics and Therapy]. / Primäre Ziliendyskinesie (PCD) ­ interdisziplinäre Diagnostik und Therapie.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disease. First respiratory symptoms already occur within the first hours after birth. Major symptoms are an unexplained neonatal respiratory distress syndrome, situs inversus, persistant cough, and chronic nasal congestion, recurrent paranasal sinus disorders with or without polyps, bronchiectasis as well as male infertility. Diagnostics is complex and includes transmission electron microscopy, nasal NO assessment, high-speed video microscopy and genetic evaluations. This review gives an overview over the current diagnostic procedures and therapeutic options. The management of PCD is a multidisciplinary approach, which should be reserved to in highly specialized centers.

Investigation of Cellular Function and DNA Integrity during 2D in vitro Culture of Human Salivary Gland Epithelial Cells.

In vitro culture of human salivary gland epithelial cells (SGEC) is still a challenge. A high quantity and quality of cells are needed for the cultivation of 3D matrices. Furthermore, it is known that DNA damage is supposed to be an important factor involved in carcinogenesis. This study investigates cellular function and DNA integrity of human SGEC during 3 passage steps in 2 groups (group 1: n = 10; group 2: n = 9). Cellular function was analyzed by immunofluorescence, transmission electron microscopy (TEM), and quantitative real-time polymerase chain reaction (qPCR). DNA integrity was tested via the comet assay. Immunohistochemistry and qPCR results showed stable α-amylase and pan-cytokeratin levels; TEM revealed functional cells; and no significant DNA damage could be detected in the comet assay during 3 culture steps. The study shows that not only at cellular but also at DNA level human SGEC can be safely quantified over 3 passages for preclinical tissue engineering without loss of differentiation and function.

[Microvascular reconstruction of the larynx following total laryngectomy]. / Mikrovaskuläre Kehlkopfrekonstruktion nach totaler Laryngektomie.

Total laryngectomy still is a standard procedure for the treatment of advanced laryngeal or hypopharyngeal carcinoma. The unavoidable loss of voice may lead to serious impairments in quality of life. The most common technique of voice restoration is the tracheal-esophageal puncture combined with the application of a voice prosthesis. Laryngeal reconstruction with a radial forearm flap represents a possible surgical method of voice restoration. This study is a mono-center retrospective analysis of patients receiving a so-called laryngoplasty after total laryngectomy between 2006 and 2015, focusing on long-term functional outcome and complications. 39 patients were included. Sufficient phonation was possible in 77 %, finger-free speaking was achieved in 62 %. Exclusion of irradiated patients revealed a rehabilitation rate of 91 %. The most common early complication was cervical hematoma in 15 %, whereas no loss of flap was assessed. Stenosis of the laryngoplasty was seen in 7 cases, mainly post-irradiation. The rate of successful voice restoration is equal in both, laryngoplasty and voice prosthesis patients. However, voice quality is better after surgical reconstruction. Complications induced by the voice prosthesis, which may be severe in some cases, were not seen in the study group. Furthermore, life-long support by an ENT specialist regarding voice prosthesis exchange is not necessary. Assuming correct choice of candidates, laryngoplasty is a sufficient method for voice restoration after laryngectomy.

[Mesenchymal stem cells: Cancer promoting effects or tumor suppression - A current overview]. / Mesenchymale Stammzellen: Tumorfördernde oder -hemmende Eigenschaften ­ Ein aktueller Überblick.

The multimodal treatment of cancer deals with cancer cells as well as with the cancer surrounding stroma. This stroma contains non-malignant cells like fibroblasts, immune cells as well as mesenchymal stem cells (MSC). MSC have the ability to migrate towards cancer tissue. In the current literature the impact of MSC on cancer cells is discussed divergently. The majority of the current publications reveal an induction of cancer progression by MSC. Four main processes namely the secretion of soluble factors and cell-cell contact, the transdifferentiation of MSC into carcinoma associated fibroblasts, the improvement of neoangiogenesis and the induction of immune suppression are responsible for cancer progression. This publication gives an overview on the current literature.

Perioperative changes in osteopontin and TGFß1 plasma levels and their prognostic impact for radiotherapy in head and neck cancer.

BACKGROUND: In head and neck cancer little is known about the kinetics of osteopontin (OPN) expression after tumor resection. In this study we evaluated the time course of OPN plasma levels before and after surgery. METHODS: Between 2011 and 2013 41 consecutive head and neck cancer patients were enrolled in a prospective study (group A). At different time points plasma samples were collected: T0) before, T1) 1 day, T2) 1 week and T3) 4 weeks after surgery. Osteopontin and TGFß1 plasma concentrations were measured with a commercial ELISA system. Data were compared to 131 head and neck cancer patients treated with primary (n = 42) or postoperative radiotherapy (n = 89; group B1 and B2). RESULTS: A significant OPN increase was seen as early as 1 day after surgery (T0 to T1, p < 0.01). OPN levels decreased to base line 3-4 weeks after surgery. OPN values were correlated with postoperative TGFß1 expression suggesting a relation to wound healing. Survival analysis showed a significant benefit for patients with lower OPN levels both in the primary and postoperative radiotherapy group (B1: 33 vs 11.5 months, p = 0.017, B2: median not reached vs 33.4, p = 0.031). TGFß1 was also of prognostic significance in group B1 (33.0 vs 10.7 months, p = 0.003). CONCLUSIONS: Patients with head and neck cancer showed an increase in osteopontin plasma levels directly after surgery. Four weeks later OPN concentration decreased to pre-surgery levels. This long lasting increase was presumably associated to wound healing. Both pretherapeutic osteopontin and TGFß1 had prognostic impact.

The Proinflammatory Potential of Nitrogen Dioxide and Its Influence on the House Dust Mite Allergen Der p 1.

Asthma and allergies are both major global health problems with an increasing prevalence, and environmental data implicate an influence of air pollutants on their development. The present study focuses on the influence of nitrogen dioxide (NO2) and the major allergen of the house dust mite Der p 1 on human nasal epithelial cells of nonallergic patients in vitro. Nasal epithelial mucosa samples of 11 donors were harvested during nasal air passage surgery and cultured as an air-liquid interface. Exposure to 0.1, 1 and 10 ppm NO2 or synthetic air as a control was performed for 1 h. Subsequently, the cells were exposed to Der p 1 for 24 h. The release of interleukin (IL)-6 and IL-8 was measured by ELISA, and the production of IL-6 mRNA and IL-8 mRNA was measured by RT-PCR. NO2 exposure resulted in a concentration-dependent release of IL-6, but not IL-8 release. The coexposure of 0.1 ppm NO2 and Der p 1, or 1 ppm NO2 and Der p 1 significantly increased both IL-6 and IL-8 release. Exposure to NO2, Der p 1, or their combination, did not significantly influence the production of IL-6 or IL-8 mRNA. In conclusion, NO2 increases the release of inflammatory cytokines in human nasal epithelial cells, especially in coexposure with Der p 1, as a mechanism of allergotoxicology.