Search Results (141)

Background: Eosinophilic chronic rhinosinusitis (ECRS) is characterized by refractory nasal polyps and severely impaired mucociliary clearance (MCC). The molecular mechanisms underlying the modulation of mucociliogenesis following IL-4/13 blockade with dupilumab remain poorly understood, notwithstanding its proven clinical efficacy. Methods: Bulk RNA Barcoding and sequencing (BRB-seq) was performed on nasal polyp tissues collected from healthy controls (n = 6), patients with non-ECRS (n = 8), and patients with ECRS both before and four weeks after dupilumab treatment (n = 9) to identify the early molecular drivers underlying ciliary regeneration. Comprehensive gene-set scoring systems were developed to evaluate multiciliogenesis master regulators, master regulators of core/ciliary planar cell polarity (PCP) and PCP components. Interaction scores for epithelial-derived cytokines—thymic stromal lymphopoietin (TSLP), IL-25, and IL-33—were calculated based on ligand and cognate receptor subunit expression. Results: The ciliary master regulatory hierarchy (e.g., FOXJ1, RFX2/3), PCP components (CELSR1 and the ciliogenesis and planar polarity effector (CPLANE) module: FUZ, INTU, WDPCP), and structural ciliogenesis pathways were robustly restored following IL-4/13 blockade. The TSLP interaction score correlated with global mucosal damage, serving as a trigger for compensatory multiciliogenesis. The pre-treatment IL-33 interaction score emerged as a significant predictor of transcriptomic ciliary recovery (p < 0.05). DNASE1L3—the primary endonuclease for degrading eosinophilic extracellular traps (EETs)—remained persistently downregulated post-treatment. Conclusions: IL-4/13 blockade successfully restores the structural and directional “hardware” of the respiratory epithelium but fails to rectify the enzymatic “software” required for mucus degradation. This “residual molecular scar” may explain the persistent mucus hyperviscosity observed in some ECRS patients even after clinical polyp resolution. Full article

Eosinophils are multifunctional granulocytes that reside constitutively within mucosal tissues, where they engage in bidirectional communication with the epithelial cells lining the respiratory and gastrointestinal (GI) tracts. Once regarded solely as terminal effectors of the type 2 immunity, eosinophils are now recognized as key regulators of epithelial homeostasis and barrier integrity. Epithelial cells initiate crosstalk by releasing the alarm cytokines such as interleukin (IL)-33, thymic stromal lymphopoietin (TSLP), and IL-25, which drive eosinophil recruitment, activation, and tissue retention. Conversely, eosinophils modulate epithelial function through the release of granule proteins, cytokines, and growth factors with both damaging and reparative consequences. In the airway, this crosstalk underpins the pathogenesis of eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), in part via eosinophil-derived mediators that disrupt tight junction integrity and fuel remodeling. In the GI tract, homeostatic eosinophils support villous architecture, epithelial turnover, and goblet cell differentiation through microbiota-driven IL-33 signals and neuropeptide-mediated neuroimmune pathways, whereas dysregulated crosstalk promotes eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD). This review synthesizes recent research to delineate the molecular mechanisms of eosinophil–epithelial crosstalk across mucosal compartments, highlight tissue-specific differences and shared mechanistic themes, and discuss the implications of these findings for targeted therapy. Full article

Background/Objectives: The emergence of SARS-CoV-2 variants and breakthrough infections underscores the need for next-generation vaccines capable of protecting from natural infection and/or preventing virus transmission. Intranasal vaccination offers a promising approach by eliciting local immune responses in the nasal mucosa, the primary site of infection and reservoir for transmissible virus. We evaluated two live-attenuated, respiratory syncytial virus-vectored vaccines in which the RSV F and G surface glycoproteins were replaced with a chimeric SARS-CoV-2 Spike protein from the ancestral USA/WA-1/2020 strain (MV-014-212) or the Delta variant (MV-014-212-delta). Methods: K18-hACE2 mice and LVG Syrian hamsters were vaccinated with a single intranasal dose of MV-014-212 or MV-014-212-delta. Systemic and mucosal immunity were assessed following vaccination, and protection was evaluated following Delta SARS-CoV-2 challenge. In vaccinated hamsters, morbidity, viral shedding, and lung inflammation and injury were also assessed following natural exposure to infected cagemates. Results: A single intranasal dose of either vaccine elicited systemic and mucosal immunity in K18-hACE2 mice, including serum neutralizing antibodies, Spike-specific memory B cells and plasmablasts, and Spike-specific CD8⁺ lung-resident memory T cells. Although MV-014-212-delta vaccination provided the best protection against the Delta variant virus challenge, both vaccines decreased viral loads in nasal discharge, lung, and brain, and reduced weight loss and mortality. In naturally acquired infection studies, vaccinated hamsters exposed to infected cagemates exhibited minimal weight loss, limited viral replication within the nasal mucosa, and attenuated lung pathology. Conclusions: Intranasal RSV-vectored vaccines can elicit broad protective respiratory immunity, suggesting that this platform could be leveraged for other respiratory pathogens. Full article

Head and neck mucosal melanoma (HNMM) arises in the nasal and oral cavities and has the propensity to metastasize to local and distant body sites. HNMM is also notable for its resistance to available therapeutics. The rarity of this disease makes it difficult to conduct large-scale clinical studies to develop standard treatment protocols. In contrast to cutaneous melanoma, c-Kit-dependent pathways are well studied in HNNMM and provide a potential therapeutic target. We identified and isolated genetically distinct subpopulations with stem cell characteristics in HNMM samples bearing Kit wild-type and mutations. Functional analysis of these subpopulations reveals that, in addition to expressing the stem cell marker proteins CD20, CD117, CD133, and CD166, these subpopulations are characterized by self-renewal potential, migratory capacity, and resistance to Kit inhibitors such as Imatinib. Immunofluorescence staining and inhibition experiments demonstrate that the maintenance and resistance of HHMM subpopulations to Kit inhibitors is mediated by the Kit signal to the PI3K signaling pathway. The KIT signal to the PI3K signaling pathway does not result exclusively from a KIT mutation localized to Exon 17, but can also be triggered by mutations localized to Exons 11 and 13. In the present study, we identify and characterize an HNMM subpopulation with stemness properties in patients with c-Kit wild-type and mutation, and demonstrate for the first time the mechanisms by which the CD117⁺/CD133⁺ HNMM subpopulations survive and confer resistance to the specific inhibitor of c-Kit mutation. Full article

Alzheimer’s disease is a complex neurodegenerative condition characterized by progressive cognitive decline, neuroinflammation, metabolic dysregulation, and abnormal protein deposition. While genetic factors and amyloid-beta-focused hypotheses have been extensively investigated, they fail to fully account for the prolonged prodromal phase or the early susceptibility of olfactory and limbic regions. Emerging evidence suggests chronic peripheral and mucosal infections may influence disease risk; however, mechanisms by which microbial activity outside the central nervous system contributes to persistent neuropathology remain poorly understood. This review explores the emerging concept that bacterial outer membrane vesicles act as mobile, lipid-rich vectors linking peripheral microbial reservoirs to neuroimmune and metabolic dysfunction in the aging brain. We discuss evidence suggesting vesicles originating from oral, olfactory, and upper airway niches can access the central nervous system via vascular routes and direct neural pathways, including olfactory and trigeminal nerves, where they influence glial and endothelial cell function. We also propose the Accumulative Vesicle Load Hypothesis, which describes how cumulative lifetime exposure to bacterial vesicles shapes disease onset, anatomical vulnerability, and progression, and incorporates components of other hypotheses proposed for Alzheimer’s disease. This offers a system-level perspective for early diagnosis and upstream therapeutic strategies, including minimally invasive vesicle profiling in nasal fluid, saliva, blood, and cerebrospinal fluid. This work is a conceptual review that summarizes current evidence in a hierarchically organized manner and proposes a testable model; it does not assert causality where direct human evidence is currently limited. Full article

Endoscopic sinus surgery (ESS) is commonly performed to treat chronic rhinosinusitis and selected sinonasal tumors, yet postoperative complications such as neo-osteogenesis and restenosis remain frequent, largely due to impaired mucosal regeneration after extensive epithelial and bony tissue loss. Successful nasal epithelial repair requires a microenvironment that preserves cell viability, phenotype, and barrier integrity. Conventional culture substrates often lack physiological relevance or rely on animal-derived components, limiting translational applicability. In this study, we evaluated nanofibrillar cellulose (NFC) hydrogel (GrowDex^®) as a xeno-free scaffold for primary human nasal epithelial cells (NECs). NECs isolated from healthy donor tissue were characterized by immunofluorescence and qPCR for basal, goblet, and ciliated cell markers. Cells embedded in NFC were assessed for viability, cytotoxicity, epithelial morphology, and barrier function. Transepithelial electrical resistance (TEER) and FITC-dextran permeability assays were used to quantify barrier integrity and compared with collagen- and polylysine-based controls. NECs cultured in NFC maintained high viability, stable epithelial morphology, and preserved subtype-specific marker expression without detectable cytotoxicity. NFC-supported cultures demonstrated enhanced barrier formation, indicated by higher TEER values and reduced paracellular permeability relative to controls, and sustained structural integrity during extended culture. These findings identify NFC hydrogel as a biocompatible, non-animal scaffold that supports functional human nasal epithelium regeneration and may contribute to advanced tissue engineering strategies for craniofacial bone repair. Full article

Background/Objectives: Hand, foot, and mouth disease (HFMD) is a major public health concern primarily caused by human enterovirus A71 (EV-A71), coxsackievirus A16 (CVA16), coxsackievirus A6 (CVA6), and certain coxsackievirus B serotypes. Currently available EV-A71 vaccines lack cross-protective efficacy against other serotypes, highlighting the urgent need for multivalent and broadly effective enterovirus vaccines. Methods: Immunoinformatics approaches were used to predict highly immunogenic B-cell and T-cell epitopes, which were assembled to construct a novel multivalent epitope vaccine, rCV-A3V, followed by in silico validation. Recombinant protein expression was confirmed by Western blotting and immunofluorescence assays. The immunogenicity was evaluated in Balb/c mice following intranasal immunization. Results: A preliminary safety evaluation demonstrated that the rCV-A3V vaccine was well tolerated in the mouse model, with no abnormal changes in body weight observed after immunization. In addition, the target protein was successfully expressed. Intranasal immunization induced a strong Th1-biased immune response, robust serum neutralizing and IgG antibody responses, and pronounced mucosal immunity, including elevated sIgA and IgG levels in nasal lavage fluid, sIgA in feces, and substantial sIgA responses in milk. Dominant epitope peptides were also identified. Conclusions: The intranasal live attenuated rCV-A3V vaccine successfully induced humoral, mucosal, and cellular immune responses against EV-A71, CVA16, CVA6, and CVB3, demonstrating broad immunogenicity. These findings provide experimental evidence supporting its potential as a candidate vaccine for HFMD. Full article

Lactoferrin (LF) is present in tears, nasal secretions, saliva, and milk and maintains mucosal homeostasis. The palatine tonsils represent the first immune tissue to recognize pathogens invading the oral cavity via Toll-like receptors (TLRs). We aimed to investigate the effects of bovine LF on tonsillar immune cells stimulated with ligands of TLR7 or TLR9, which recognize viral single-stranded RNA or bacterial unmethylated CpG DNA. Mononuclear cells isolated from palatine tonsils of patients with recurrent tonsillitis or immunoglobulin A (IgA) nephropathy were cultured with LF, TLR7, or TLR9 ligands. Under TLR7 stimulation, LF enhanced the activation of plasmacytoid dendritic cells (pDCs), T-killer cells, and B cells without inducing inflammatory cytokines. In contrast, under TLR9 stimulation, LF suppressed the activation of pDCs, myeloid dendritic cells, T-helper cells, T-killer cells, B cells, and natural killer cells, as well as the production of TNF-α and IL-6. Moreover, LF decreased the production of the B-cell activation factor (BAFF), a proliferation-inducing ligand (APRIL), and galactose-deficient IgA1, all of which are risk factors of IgA nephropathy. Overall, LF may enhance the immune response against viruses and contribute to immune tolerance against commensal bacteria in the palatine tonsils, indicating potential benefits in managing cold-like symptoms, recurrent tonsillitis, and IgA nephropathy. Full article

The nasal mucosa functions as a highly specialized barrier that integrates epithelial, stromal, neuronal, and immune signals to maintain homeostasis and mount rapid responses to environmental challenges. Among its resident immune populations, innate lymphoid cells—particularly type 2 ILCs (ILC2s)—play a pivotal role in orchestrating type 2 inflammation driven by epithelial-derived alarmins such as IL-25, IL-33, and TSLP. Upon activation, ILC2s release IL-5 and IL-13, promoting eosinophilic inflammation, goblet cell hyperplasia, mucus hypersecretion, and tissue remodeling, all central features of chronic rhinosinusitis with nasal polyps (CRSwNP) and severe allergic rhinitis. Recent advances have revealed substantial ILC plasticity, the presence of nasal-resident ILC progenitors, and the influence of metabolic and neuroimmune cues in shaping ILC activation and persistence. Dupilumab, a monoclonal antibody targeting IL-4Rα, has emerged as a highly effective therapy, providing unique mechanistic insight into the epithelial–ILC axis. By blocking IL-4/IL-13 signaling, dupilumab dampens ILC2 effector functions, reduces IL-5/IL-13 output, restores epithelial barrier integrity, interrupts alarmin-driven amplification loops, and rebalances innate and adaptive immune networks. Clinical and translational studies indicate that baseline ILC2 phenotypes—particularly inflammatory ILC2 subsets—may predict treatment responsiveness, positioning ILC profiling as a promising biomarker strategy. This review synthesizes current knowledge of ILC classification, plasticity, progenitor biology, and epithelial–ILC communication in the nasal mucosa, while integrating emerging evidence on dupilumab-mediated immunomodulation. Collectively, these insights highlight ILCs as central drivers of type 2 inflammation and key targets for precision immunomodulation, offering a framework for personalized treatment approaches in CRSwNP and allergic rhinitis. Full article

Epithelial barrier dysfunction is increasingly recognized as a central pathogenic mechanism in chronic inflammatory airway diseases characterized by type 2 immune responses. Chronic rhinosinusitis with nasal polyps (CRSwNP) represents a paradigmatic condition in which structural epithelial alterations, impaired barrier integrity, and sustained release of epithelial-derived alarmins interact with innate and adaptive immune pathways to drive persistent inflammation and tissue remodeling. In this context, understanding disease heterogeneity requires tools capable of capturing cellular and immunological complexity beyond purely molecular or symptom-based classifications. Nasal cytology is a standardized, minimally invasive, and repeatable technique that provides direct in vivo assessment of epithelial morphology and inflammatory cell infiltrates at the mucosal surface. By identifying distinct cytological patterns, including eosinophil-dominant, mast cell-rich, and mixed inflammatory signatures, nasal cytology reflects the underlying immunopathological mechanisms of CRSwNP and correlates with disease severity, clinical control, and therapeutic responsiveness. Its dynamic nature allows longitudinal monitoring of inflammatory changes over time, offering insights that complement clinical evaluation and endoscopic assessment. This review integrates current knowledge on epithelial barrier dysfunction and type 2 inflammation with the translational relevance of nasal cytology in CRSwNP. Particular attention is given to its role in disease phenotyping, prognostic stratification, and monitoring of biologic therapies. Within precision medicine frameworks, nasal cytology emerges as a robust cellular biomarker bridging epithelial biology, immune profiling, and personalized clinical decision-making. Full article

Background/Objectives: Respiratory Syncytial Virus (RSV) causes severe disease in infants, the elderly, and immunocompromised individuals, with reinfections linked to poor induction of durable mucosal immunoglobulin A (IgA). We investigated the role of IgA in immunity and protection induced by a RSV subunit vaccine candidate, tFrsc/TriAdj, which consists of a truncated RSV fusion protein (tFrsc) with a tri-component adjuvant (TriAdj). Methods: Wild-type (IgA⁺/⁺) and IgA-deficient (IgA⁻/⁻) BALB/c mice were immunized intranasally and subsequently challenged with RSV. Results: Vaccination with tFrsc/TriAdj induced robust systemic and mucosal IgG, and high lung and serum neutralizing antibodies, in both IgA⁺/⁺ and IgA⁻/⁻ mice. As expected, IgA⁻/⁻ mice lacked IgA and exhibited modest reductions in nasal IgG compared to IgA^+/+ mice following challenge, correlating to failure to clear RSV from the upper respiratory tract. In contrast, viral replication in the lungs was fully suppressed in both genotypes, indicating that IgG alone was sufficient for lower respiratory tract protection. Isotype analysis revealed diminished Th1-associated IgG2a and elevated IgG1 across mucosal and systemic compartments in IgA⁻/⁻ mice, suggesting a Th2 bias. Flow cytometric analysis confirmed reduced recruitment of IFN-γ⁺ CD4⁺ T cells in the lungs of immunized IgA⁻/⁻ mice. Interestingly, IL-17 production and numbers of IL-17⁺ CD4⁺ T cells in the lungs were increased, suggesting an enhanced Th17 response. Furthermore, IgA-deficient mice displayed reduced splenic IgG⁺ B cell populations, which is also a novel observation. Conclusions: Collectively, these findings demonstrate that although tFrsc/TriAdj confers lower airway protection in the absence of IgA, vaccine-induced IgA is critical for upper airway protection, Th1/balanced immune responses, and optimal B cell responses. Full article

Background/Objectives: Allergic rhinitis (AR) is a complex immune-mediated disorder characterized by defective regulatory mechanisms. Emerging evidence suggests that impaired immune tolerance mediated by regulatory B cell (Breg) plays a pivotal role in AR pathogenesis. This study investigates the therapeutic potential of Der p1 allergen-modified dendritic cells (DC) in enhancing Breg-mediated immunotherapy and explores novel mechanisms underlying AR immunomodulation. Methods: Breg and the inflammatory cytokines were detected before and after allergen immunotherapy (AIT) in AR patients. Dust mite gene-derived dendritic cells were used to induce Breg. AR mice were treated with Der p1-DCs, and changes in Breg and related inflammatory indicators, as well as the impact of the IL-10/STAT pathway on DC vaccine treatment, were observed. Results: Following 6-month AIT, AR patients exhibited significant alleviation of nasal symptoms alongside restored peripheral Breg and Treg. In vitro co-culture of Der p1-DC-induced Bregs with CD4⁺CD25⁻T cells revealed that IL-10 blockade markedly increased Th cell. In AR murine models, intraperitoneal Der p1-DC administration suppressed allergic symptoms, upregulated nasal mucosal IL-10 expression, and attenuated STAT3 phosphorylation via IL-10 overexpression. Conclusions: AIT establishes immune tolerance through Breg-mediated regulatory mechanisms, while Der p1-DCs potently induce Breg differentiation and drive tolerance induction via the IL-10/STAT3 signaling axis. Full article

American tegumentary leishmaniasis (ATL) and other infectious granulomatous diseases (IGDs) may present with oral/oropharyngeal mucosal lesions (OOPML). IGD-OOPML can result from fungal, parasitic, or bacterial infections, and squamous cell carcinoma (SCC) represents the main differential diagnosis. ATL, other IGD, and SCC share overlapping clinical and epidemiological features, making diagnostic suspicion challenging. This study compared sociodemographic and clinical characteristics among ATL, other IGD, and SCC. Descriptive, comparative, and multivariable logistic regression analyses were performed. Among 7551 patients, 213 met inclusion criteria (83-SCC and 130-IGD). Except for smoking, which differed only between ATL and SCC, most IGD parameters were similar. Male patients predominated in all groups. SCC patients were significantly older (p < 0.001) and had a shorter median disease duration (p = 0.007). The presence of pain increased the odds of SCC-OOPML by 3.96 times (95% CI 1.97–12.51). SCC patients were more likely to present lesions in a single subsite, either the oral cavity or oropharynx. Painful, ulcerated, or exophytic lesions favored SCC diagnosis, whereas infiltrative, granular, or mulberry-like lesions, involvement of multiple subsites, or associated nasal and laryngeal lesions suggested IGDs. Although clinical differentiation remains difficult, these findings may support early diagnostic suspicion, prompt treatment, and reduced sequelae. Full article

Background: Naegleria fowleri is a free-living amoeba that inhabits warm freshwater and causes primary amoebic meningoencephalitis (PAM), a rapidly fatal infection with >95% mortality. Due to the lack of early diagnosis and effective therapy, preventive vaccination represents a promising strategy. Methods: This study evaluated short- and long-term immune protection in BALB/c mice (20 mice per group) immunized intranasally with total N. fowleri extract co-administered with cholera toxin (CT). Mice were challenged with a lethal dose of trophozoites either 24 h (short-term) or three months (long-term) after the fourth immunization; the latter group received a booster 24 h before challenge. Serum and nasal washes were analyzed for IgA and IgG antibodies by immunoblot, and lymphocyte subsets from nasal-associated lymphoid tissue (NALT) and nasal passages (NPs) were characterized by flow cytometry. Results: Immunization conferred complete (100%) survival in the 24 h group and 60% protection in the 3-month group, whereas all control mice died. Immunoblotting showed that IgA and IgG antibodies recognized major N. fowleri antigens of 37, 45, 48 and 19, 37, and 100 kDa, respectively. Flow cytometry revealed increased activated and memory B lymphocytes, dendritic cells, and expression of CCR10, integrin α4β1, and FcγRIIB receptors, particularly in the 24 h group. Conclusions: Intranasal immunization with N. fowleri extract plus CT elicited both systemic and mucosal immune responses capable of short- and long-term protection. These findings highlight the potential of this immunization strategy as a foundation for developing effective vaccines against PAM. Full article

Background/Objectives: In recent years, the recognition that type 2 inflammation plays a leading role in CRSwNP has enabled the more tailored treatment of the disease through improved patient endotyping. We studied 45 patients with severe CRSwNP who were treated with dupilumab or mepolizumab. The aim was to evaluate the efficacy of these treatments on endoscopic, clinical and patient reported parameters, and to assess whether nasal cytology could be useful for identifying responsive patients and monitoring their response to biologic drugs. Methods: Follow-up visits were scheduled at baseline (T0), and at 3 (T3), 6 (T6), 12 (T12), and 24 months (T24). At each visit, patients underwent blood analysis, nasal endoscopy, and nasal scraping for cytology. They also completed the SNOT-22 questionnaire, a visual analog scale (VAS) for nasal obstruction and smell perception, and the Asthma Control Test (ACT) test in cases of concomitant asthma. Results: Biological therapy demonstrated broad efficacy in disease management, based on both clinical and cytological findings. The Nasal Polyp Score, SNOT-22 questionnaire, VAS scores for nasal obstruction and smell, and ACT score showed progressive improvement. Blood eosinophil counts and total IgE levels also decreased over time (T0 vs. T24: p = 0.008 and p < 0.001, respectively). At nasal cytology, a reduction in eosinophil cell count and in the mixed mast cell–eosinophil pattern during treatment with both biologics were observed (T0 vs. T24: p < 0.001). Positive effects were typically recorded within six months of treatment and were sustained after two years. Conclusions: Although the histological evaluation of infiltrated tissues remains the gold standard for assessing mucosal eosinophilia, nasal cytology appears to be a simpler, non-invasive, and repeatable method for evaluating local eosinophilia. Identifying endotypes and assessing the severity of inflammation are crucial for predicting the efficacy of different treatment options. Full article