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BackgroundAcute invasive fungal sinusitis (AIFS) is an aggressive disease that requires prompt diagnosis and multidisciplinary treatment given its rapid progression. However, there is currently no consensus on diagnosis, prognosis, and management strategies for AIFS, with multiple modalities routinely employed. The purpose of this multi-institutional and multidisciplinary evidence-based review with recommendations (EBRR) is to thoroughly review the literature on AIFS, summarize the existing evidence, and provide recommendations on the management of AIFS.MethodsThe PubMed, EMBASE, and Cochrane databases were systematically reviewed from inception through January 2022. Studies evaluating management for orbital, non-sinonasal head and neck, and intracranial manifestations of AIFS were included. An iterative review process was utilized in accordance with EBRR guidelines. Levels of evidence and recommendations on management principles for AIFS were generated.ResultsA review and evaluation of published literature was performed on 12 topics surrounding AIFS (signs and symptoms, laboratory and microbiology diagnostics, endoscopy, imaging, pathology, surgery, medical therapy, management of extrasinus extension, reversing immunosuppression, and outcomes and survival). The aggregate quality of evidence was varied across reviewed domains.ConclusionBased on the currently available evidence, judicious utilization of a combination of history and physical examination, laboratory and histopathologic techniques, and endoscopy provide the cornerstone for accurate diagnosis of AIFS. In addition, AIFS is optimally managed by a multidisciplinary team via a combination of surgery (including resection whenever possible), antifungal therapy, and correcting sources of immunosuppression. Higher quality (i.e., prospective) studies are needed to better define the roles of each modality and determine diagnosis and treatment algorithms.

BackgroundSolitary chemosensory cells (SCCs) are rare epithelial cells enriched in nasal polyps and are the primary source of interleukin-25 (IL-25), an innate cytokine eliciting T-helper 2 (Th2) immune response. Although it is proposed that SCCs are stimulated by antigens released by upper airway pathogens, the exogenous triggers of human SCCs remain elusive. We studied patients with noninvasive fungal rhinosinusitis to determine whether extracts of Aspergillus fumigatus and Alternaria alternata stimulate SCC proliferation as an early event in type 2 inflammation.MethodsMulticolor flow cytometry, immunofluorescence, and enzyme-linked immunoassay were used to interrogate mucosa from patients with mycetomas and allergic fungal rhinosinusitis (AFRS) for SCCs and IL-25. Primary sinonasal epithelial cells from AFRS patients and noninflamed inferior turbinates were stimulated with fungal extracts for 72 hours, and SCC population frequency as well as mitotic activity were quantified using flow cytometry.ResultsSCCs producing IL-25 are enriched in inflamed mucosa compared with intrapatient noninflamed control tissue (38.6% vs 6.5%, p = 0.029). In cultured sinonasal epithelial cells from AFRS nasal polyps, Aspergillus fumigatus and Alternaria alternata stimulated higher SCC frequency compared with controls (27.4% vs 10.6%, p = 0.002; 18.1% vs 10.6%, p = 0.046), which led to increased IL-25 secretion in culture media (75.5 vs 3.3 pg/mL, p < 0.001; 32.3 vs 3.3 pg/mL, p = 0.007). Ki-67 expression was higher in SCCs grown in fungal stimulation conditions compared with controls.ConclusionAlthough fungal antigens are known to potentiate immune response through innate cytokines, including IL-25, the early expansion of SCCs in the presence of fungus has not been described. This early event in the pathogenesis of noninvasive fungal rhinosinusitis may represent a target for intervention.

BackgroundBroncho-Vaxom® (OM-85 BV) is an extract of infectious respiratory bacteria that is used as an immunostimulant outside of the United States for the prevention and treatment of bronchitis and rhinosinusitis. Prior studies have shown that use of OM-85 BV is associated with reduction in frequency of respiratory infection and decreased duration of antibiotic usage. However, the effects of OM-85 BV on respiratory mucosal innate immunity are unknown.MethodsHuman sinonasal epithelial cells were grown at an air-liquid interface (ALI). Ciliary beat frequency (CBF) and nitric oxide (NO) production in response to stimulation with OM-85 BV was measured in vitro. Pharmacologic inhibitors of bitter taste receptor (T2R) signaling were used to determine if this pathway was taste-receptor-mediated.ResultsApical application of OM-85 BV resulted in an NO-mediated increase in CBF (p

Chronic rhinosinusitis with nasal polyps (CRSwNP) is commonly characterized by type-2 inflammation. It is established that group-2 innate lymphoid cells (ILC2s) are a subset of immune cells important in orchestrating mucosal type-2 response. IL-25 is an epithelial-derived cytokine that is a critical activator of ILC2s. Recent evidence demonstrates that specialized taster epithelial cells, such as solitary chemosensory cells (SCCs), may be producers of IL-25. To elucidate the relationship between SCCs and ILC2s in CRSwNP, we sought to quantify ILC2s and SCCs to determine if these cell types are enriched in nasal polyps compared to healthy sinonasal mucosa. We quantified SCCs and ILC2s using multicolor flow cytometry in nasal polyps and non-inflamed turbinate mucosa from seven patients and investigated the role of IL-13 and dexamethasone on SCC frequency using tissue explants of nasal polyps and turbinate mucosa. SCCs were found to be the primary source of IL-25. Nasal polyps demonstrated higher populations of SCCs (33.0% vs 5.6%, p < 0.001) and ILC2s (2.40% vs 0.19%, p = 0.008) compared to patient-matched nonpolypoid turbinates. In cultured polyp explants, exogenous IL-13 increased the proportion of epithelial SCCs (40.2% IL-13 condition vs 28.9% untreated, p = 0.012), and this effect was reversed by addition of dexamethasone (40.2% vs 8.9%, p < 0.0005). These data support SCC and ILC2 expansion as well as increased IL-25 production in nasal polyps and may represent early events in the pathogenesis of CRSwNP. IL-13 stimulates proliferation of SCC in a feed-forward loop, a process that is steroid-sensitive.

KEY POINTS: Patients treated with pembrolizumab experience an increase in paranasal sinus inflammationUse of topical triamcinolone in carboxymethylcellulose is a treatment option for such patients [ABSTRACT FROM AUTHOR]

Recent evidence has demonstrated an expanding role of respiratory epithelial cells in immune surveillance and modulation. Studies have been focusing on the earliest events that link epithelial injury to downstream inflammatory responses. Cytokines produced by and released from respiratory epithelial cells are among these early trigger signals. Epithelial‐derived cytokines, namely thymic stromal lymphopoietin (TSLP), interleukin (IL)‐25, and IL‐33, have come to the forefront of recent investigations. Each of these 3 cytokines has been implicated in chronic rhinosinusitis (CRS), asthma, and atopy. Herein we review studies elucidating the roles of epithelial‐derived cytokines in the pathobiology of upper airway disease, with particular emphasis on type 2 inflammatory conditions. [ABSTRACT FROM AUTHOR]