Eosinophilic Mucus Research Articles

Aggregated eosinophils and neutrophils characterize the properties of mucus in chronic rhinosinusitis

BackgroundAirway obstruction caused by viscous mucus is an important pathophysiological characteristic of persistent inflammation, which can result in organ damage. ObjectiveWe investigated the hypothesis that the biophysical characteristics of accumulating granulocytes impact the clinical properties of mucus. MethodsSurgically acquired nasal mucus samples from patients with eosinophilic chronic rhinosinusitis and neutrophil-dominant, non-eosinophilic chronic rhinosinusitis were evaluated in terms of computed tomography density, viscosity, water content, wettability, and protein composition. Isolated human eosinophils and neutrophils were stimulated to induce the formation of extracellular traps, followed by the formation of aggregates. The biophysical properties of the aggregated cells were also examined. ResultsMucus from patients with eosinophilic chronic rhinosinusitis had significantly higher computed tomography density, viscosity, dry weight, and hydrophobicity compared with mucus from patients with non-eosinophilic chronic rhinosinusitis. The levels of eosinophil-specific proteins in mucus correlated with its physical properties. Eosinophil and neutrophil aggregates showed physical and pathological characteristics resembling those of mucus. Co-treatment with deoxyribonuclease and heparin, which slenderizes the structure of eosinophil extracellular traps, efficiently induced reductions in the viscosity and hydrophobicity of both eosinophil aggregates and eosinophilic mucus. ConclusionsThe present study elucidates the pathogenesis of mucus stasis in infiltrated granulocyte aggregates from a novel perspective. These findings may contribute to the development of treatment strategies for eosinophilic airway diseases.

Allergic Bronchopulmonary Aspergillosis–A Luminal Hypereosinophilic Disease With Extracellular Trap Cell Death

Allergic bronchopulmonary aspergillosis (ABPA) is characterized by an early allergic response and late-phase lung injury in response to repeated exposure to Aspergillus antigens, as a consequence of persistent fungal colonization of the airways. Here, we summarize the clinical and pathological features of ABPA, focusing on thick mucus plugging, a key observation in ABPA. Recent findings have indicated that luminal eosinophils undergo cytolytic extracellular trap cell death (ETosis) and release filamentous chromatin fibers (extracellular traps, ETs) by direct interaction with Aspergillus fumigatus. Production of ETs is considered to be an innate immune response against non-phagocytable pathogens using a “trap and kill” mechanism, although eosinophil ETs do not promote A. fumigatus damage or killing. Compared with neutrophils, eosinophil ETs are composed of stable and condensed chromatin fibers and thus might contribute to the higher viscosity of eosinophilic mucus. The major fate of massively accumulated eosinophils in the airways is ETosis, which potentially induces the release of toxic granule proteins and damage-associated molecular patterns, epithelial damage, and further decreases mucus clearance. This new perspective on ABPA as a luminal hypereosinophilic disease with ETosis/ETs could provide a better understanding of airway mucus plugging and contribute to future therapeutic strategies for this challenging disease.

Rhinosinusite fongique allergique : un diagnostic à évoquer

Among fungal infections of the nasal sinuses, allergic fungal rhinosinusitis is a recently described, relatively rare and little known pathology. Its diagnosis is based on: clinical criteria (it occurs in young immunocompetent patients, often associated with bilateral nasosinusal polyposis); pathological criteria (allergic mucin: eosinophilic mucus without invasion of the sinusal mucosa and observation of fungal hyphae on surgical samples); biological criteria (hypereosinophilia, total and specific antifungal IgE); and radiological criteria. The combination of tomodensitometry (heterogeneous hyperdense and diffusefilling of nasosinusal cavities with expanded borders and a distended appearance of the bony wall), and MRI scan (extensive character and lesional signal [hypo and asignal T1and T2], and cerebriform aspect of the fungal process) strongly suggests the diagnosis. It is important to distinguish the most typical forms, as well as unusual forms of allergic fungal rhinosinusitis. Main differential diagnoses are represented by other forms of fungal nasosinusal infections with different treatment and prognosis.

Role of fungi in chronic rhinosinusitis through ITS sequencing.

Next-generation sequencing increases the sensitivity of fungal identification and may improve our understanding of the role that fungi play in sinus health and disease, which remains incompletely understood. We sequenced the internal transcribed spacer (ITS) amplicon to explore the role of the mycobiome in chronic rhinosinusitis (CRS). Swabs were collected intraoperatively from the middle meatus of 90 patients (63 with CRS; 27 controls). DNA was extracted, and ITS amplicon concentration was measured using fluorometry. Internal transcribed spacer amplicons were sequenced on the Illumina MiSeq (Illumina Inc San Diego CA). Sequencing data were analyzed using QIIME. Using conventional detection techniques of culture and histology, fungi only were identified in nine of 63 (14.3%) CRS patients (fungus-identified group); the remaining 54 CRS patients and all controls did not have fungus identified using the traditional techniques. This fungus-identified group had a significantly higher average ITS concentration and a significantly lower Shannon's diversity index compared to the other two groups. The most abundant organism sequenced was Aspergillus (35.22% of all sequences). Multivariate analysis showed that positive fungal detection using traditional techniques and computed tomography (CT) double densities were the most important clinical predictors of a high fungal biomass, whereas Lund-Mackay score, polyps, eosinophilia, and eosinophilic mucus were not significant in comparison. Fungal biomass estimated through ITS amplicon concentration correlated with traditional fungal detection techniques and CT double densities. Our results suggest that fungal dysbiosis only occurs in the sinuses of a selected subset of patients, and therefore could not be a universal determinant of sinus disease pathogenesis in all CRS patients. NA. Laryngoscope, 128:16-22, 2018.

B cell subsets are modulated during allergic airway inflammation but are not required for the development of respiratory tolerance in a murine model.

Allergic asthma is a widespread chronic inflammatory disease of the airways. The role of different B cell subsets in developing asthma and respiratory tolerance is not well known. Especially regulatory B (Breg) cells are proposed to be important in asthma regulation. Using wild-type (WT) and B cell-deficient (μMT) mice we investigated how B cells are affected by induction of allergic airway inflammation and respiratory tolerance and whether they are necessary to develop these conditions. WT mice with an asthma-like phenotype, characterized by increased airway hyper reactivity, eosinophilic airway inflammation, mucus hypersecretion and elevated Th2 cytokines, exhibited increased MHCII and CD23 expression on follicular mature B cells in lung, bronchial lymph nodes (bLN) and spleen, which contributed to allergen-specific T cell proliferation in vitro. Germinal center B cell numbers were elevated and associated with increased production of allergen-specific immunoglobulins especially in bLN. In contrast, respiratory tolerance clearly attenuated these B cell alterations and directly enhanced marginal zone precursor B cells, which induced regulatory T cells in vitro. However, μMT mice developed asthma-like and tolerized phenotypes like WT mice. Our data indicate that although B cell subsets are affected by asthma-like and respiratory tolerant phenotypes, B cells are not required for tolerance induction.

CD4+ and CD8+ regulatory T cells in chronic rhinosinusitis mucosa.

Chronic rhinosinusitis (CRS) mucosal inflammation is characterized by an accumulation of effector-memory T cells, but their immune regulatory potential has not been adequately examined. Coexpression of transcription factor, forkhead box P3 (Foxp3), and interleukin-2 receptor, CD25, in CD4+ and CD8+ T cells is linked with regulatory function in humans. The aim of this study was to investigate the regulatory T cell (Treg) phenotype of CD4+ (CD4Treg) and CD8+ (CD8Treg) T cells in peripheral blood (PB) and sinus mucosa of CRS patients. Prospective study was performed involving 32 CRS with nasal polyp (CRSwNP), 14 CRS without nasal polyp (CRSsNP), and 8 control patients. Sinus and PB T lymphocytes were stained with CD3, CD4, CD8, CD25, and Foxp3 and analyzed using flow cytometry. Relevant clinical characteristics, sinus bacterial culture results, and eosinophilic mucus were examined. Sinus mucosa had a higher percentage of CD4Treg (CD3+CD4+CD25+Foxp3+) population compared with PB in all patients. The percentage of PB CD4Treg and CD8Treg (CD3+CD8+CD25+Foxp3+) was not significantly different between the study groups. CRS mucosal tissue had a higher percentage of CD4Treg and activated T-helper cells than controls. There was no significant difference in PB and mucosal CD4Treg populations in CRS patients based on the presence of allergy, sinus culture results, or eosinophilic mucus. In controls, increased mucosal CD4Treg correlated with coexisting allergy. Although overall CD4Treg numbers were higher, the regulatory potential of activated CD4+ T cells (CD4Treg/activated T-helper cell ratio) was significantly lower in CRS mucosa compared with controls. The CD8Treg subset was also significantly reduced in CRSwNP mucosa compared with controls. A higher percentage of CD4Treg and activated T-helper cells in CRS mucosa suggests increased inflammation in CRS, independent of the presence of allergy, microbial culture results, or eosinophilic mucus. However, the decreased ratio of CD4Treg versus activated T-helper cells in CRS and reduced CD8Treg population in CRSwNPs indicates an inflammatory bias and the inability to control mucosal disease.

CD8(+) T cells implicated in the pathogenesis of allergic fungal rhinosinusitis.

Fungi in paranasal sinuses are characteristic and considered a major pathogenic factor in a subset of chronic rhinosinusitis (CRS) patients, known as allergic fungal rhinosinusitis (AFRS). CD8+ T cells are enriched in AFRS sinuses but their role in fungal-specific responses is unknown. Alternaria alternata– and Aspergillus fumigatus–specific T lymphocyte responses were investigated in 6 AFRS patients, 10 eosinophilic mucus CRS (EMCRS) patients, 10 CRS with nasal polyps (CRSwNPs) patients, 6 allergic rhinitis with fungal allergy (ARFA) patients, and five controls. Fungal-specific proliferation of human peripheral blood mononuclear cells (PBMCs) was studied prospectively. Proliferating cells were examined for CD3, CD4, CD8, and CD25 expression. Relevant clinical characteristics, fungal allergy, detection of fungi in sinuses, and CD4+ and CD8+ composition of sinus T cells were also examined. CD4+ T-cell division to fungi occurred in all samples, regardless of fungal allergy or CRS. Fungal-specific CD8+ T-cell division occurred in all ARFA and control samples and the majority of CRSwNP patients; however, CD8+ T cells failed to proliferate in AFRS and EMCRS patients. The CD8+ T cells from AFRS patients also did not up-regulate the activation marker, CD25, with fungal antigen exposure. Presence of A. alternata– and A. fumigatus–specific CD4+ and CD8+ T-cell proliferation in healthy individuals, ARFA, and CRSwNP patients suggests that both T-cell subsets may be important in immune responses to these fungi. In AFRS and EMCRS patients, only fungal-specific CD4+ T-cell proliferation occurred; hence, a lack of CD8+ T-cell proliferation and activation in the presence of sinus eosinophilic mucus in these patients, regardless of fungal allergy, is a novel finding. This raises the question whether a dysfunctional CD8+ T-cell response predisposes to ineffective clearance and accumulation of fungi in the sinuses of susceptible patients.

Accumulation of Effector Memory CD8+ T Cells in Nasal Polyps

T lymphocytes are prevalent in sinus mucosa and are implicated in chronic rhinosinusitis (CRS) pathogenesis. However, the major T-cell subpopulations, helper (CD4+) and cytotoxic (CD8+), have not been adequately examined in CRS. This study was designed to characterize human sinus mucosa and peripheral blood (PB) CD4+ and CD8+ T cells and their level of differentiation in CRS with nasal polyps (NPs), CRS without NPs, and control patients. A prospective study was performed. Percentages of CD4+ and CD8+ T cells and their levels of differentiation were analyzed in sinus mucosa and PB by flow cytometry. Cell populations were defined as naive, central memory, effector memory, and effector T cells using cell surface markers CD45RA, CD62L, and CD27. The influence of coexisting allergy, sinus eosinophilic mucus (EM), and culture results were examined. In all patients, sinus mucosa had a lower percentage of CD4+ and a higher percentage of CD8+ T cells compared with PB. However, CRS with NPs (n = 86) had a significantly higher percentage of mucosal CD8+ T cells compared with CRS without NPs (n = 40) in control (n = 13) patients (p < 0.0001). Effector memory T cells were increased in sinuses compared with PB in all patients; however, the percentage of effector memory CD8+ T cells was greatest in CRS with NP mucosa (p = 0.002). Surprisingly coexisting allergy or culture results did not influence the mucosal T-cell phenotype. CRS with NP patients with sinus EM had a significantly higher percentage of mucosal CD8+ T cells. Sinus mucosa in CRS with NPs is characterized by a significant enrichment of CD8+ T cells and a relative deficiency of CD4+ T cells. The majority of NP CD8+ T cells had a terminally differentiated, mature, effector memory phenotype, which raises the question, whether these cells are pathogenic or appear as a consequence of inflammation, independent of the presence of allergy or positive microbial culture.

IL-17A in Asthma - A Question of Severity

Allergic asthma is a chronic inflammatory disease of the lung driven by aberrant responses to normally innocuous environmental allergens. Disease is characterized by excessive IgE synthesis, eosinophilic pulmonary inflammation, mucus hypersecretion, and airway remodeling, and airway hyperresponsiveness - all leading to the clinical features of disease - reversible episodes of coughing, shortness of breath and wheezing. While the excessive production of cytokines like IL-4, IL-5 and IL-13 by allergen specific-Th2 cells is sufficient to explain most features of allergic asthma, increasing evidence suggests that the Th2 paradigm does not explain the full spectrum of disease severity. In particular, severe asthmatics represent a small subset of asthmatics, in which disease is associated with more severe airway reactivity, a mixed eosinophilic/neutrophilic infiltrate, and insensitivity to treatment with corticosteroids. Thus, severe asthmatics are not only more susceptible asthma-related complications; they are underserved by currently available therapies. Recent evidence suggests that the development of severe disease may be associated with the development of a mixed Th2/Th17 response. Herein, we will assess the data from human and animal models suggesting a link between a mixed Th2/Th17 response, and the development of severe asthma. A greater understanding of the mechanisms responsible for the development of severe asthma may allow the development of efficacious therapeutics for the treatment of this intractable form of disease.

Daclizumab: A Potential Asthma Therapy?

Airways inflammation in asthma is triggered and maintained by CD4+ (Th2) cells which are activated by IL-2 and stimulate the eosinophilic inflammation, IgE secretion and mucus hyperproduction. Current anti-inflammatory therapies include inhaled corticosteroids, and leukotriene modifiers but they are not universally effective. IL-2 pathway inhibition might represent a potent anti-inflammatory therapy in asthma given the cytokine early role in the asthma complex inflammatory cascade and daclizumab which is a IL-2R blocker currently used as an immunsupressor in organ transplantation might be a potential asthma therapy. This is review on the pathogenic role of IL-2, on the therapeutic potential of daclizumab and on its related patents.

Nasal Polyp Cell Populations and Fungal-Specific Peripheral Blood Lymphocyte Proliferation in Allergic Fungal Sinusitis

Background Allergic fungal sinusitis (AFS) is considered a different disease from other polypoid chronic rhinosinusitis diseases (CRS) with eosinophilic mucus (EM) termed eosinophilic mucus chronic rhinosinusitis (EMCRS). To substantiate this, studies on cellular responses to fungi and sinus mucosal inflammatory cell populations in AFS and other EMCRS diseases are. required. This study was designed to examine polyp inflammatory cell populations and peripheral blood fungal-specific T-cell responses in AFS, other EMCRS subgroups (defined later), and polypoid CRS without EM. Methods A prospective study was performed. Clinical characteristics, including CRS symptoms, sinus computed tomography (CT) scans, allergy status, intraoperative endoscopy, presence of EM, and fungal culture results were used to define patient groups. Polyps and peripheral blood were examined for populations of eosinophils, lymphocytes (CD4+, CD8+ T cells, natural killer cells, and B cells), and neutrophils using immunohistochemistry, cytospin preparations and flow cytometry. Fungal-specific peripheral blood lymphocyte proliferation was examined in AFS patients, other EMCRS patients, CRS patients, and controls. Results There was no significant difference in the percentage of cell populations and fungal-specific lymphocyte proliferation between AFS and other EMCRS diseases. However, AFS and other EMCRS polyps had a higher percentage of eosinophils and CD8+ T cells whereas CRS polyps had higher CD44 T cells. Fungal-specific lymphocyte proliferation was significantly greater in AFS and other EMCRS patients regardless of fungal allergy, whereas in CRS and controls, higher proliferation was observed in fungal-allergic individuals. Conclusion These findings question the basis for differentiating AFS from, other EMCRS diseases based on fungal allergy and fungi in EM. Fungal-specific cellular response was present in AFS and other EMCRS diseases, different from, that associated with fungal allergy, suggesting a nonallergic fungal immune response. Increased CD8+ T cells in EMCRS polyps signify a different type of inflammation to CRS that may be driven by CD8+ T cells.

Nasal polyp cell populations and fungal-specific peripheral blood lymphocyte proliferation in allergic fungal sinusitis.

Allergic fungal sinusitis (AFS) is considered a different disease from other polypoid chronic rhinosinusitis diseases (CRS) with eosinophilic mucus (EM) termed eosinophilic mucus chronic rhinosinusitis (EMCRS). To substantiate this, studies on cellular responses to fungi and sinus mucosal inflammatory cell populations in AFS and other EMCRS diseases are required. This study was designed to examine polyp inflammatory cell populations and peripheral blood fungal-specific T-cell responses in AFS, other EMCRS subgroups (defined later), and polypoid CRS without EM. A prospective study was performed. Clinical characteristics, including CRS symptoms, sinus computed tomography (CT) scans, allergy status, intraoperative endoscopy, presence of EM, and fungal culture results were used to define patient groups. Polyps and peripheral blood were examined for populations of eosinophils, lymphocytes (CD4+, CD8+ T cells, natural killer cells, and B cells), and neutrophils using immunohistochemistry, cytospin preparations and flow cytometry. Fungal-specific peripheral blood lymphocyte proliferation was examined in AFS patients, other EMCRS patients, CRS patients, and controls. There was no significant difference in the percentage of cell populations and fungal-specific lymphocyte proliferation between AFS and other EMCRS diseases. However, AFS and other EMCRS polyps had a higher percentage of eosinophils and CD8+ T cells whereas CRS polyps had higher CD4+ T cells. Fungal-specific lymphocyte proliferation was significantly greater in AFS and other EMCRS patients regardless of fungal allergy, whereas in CRS and controls, higher proliferation was observed in fungal-allergic individuals. These findings question the basis for differentiating AFS from other EMCRS diseases based on fungal allergy and fungi in EM. Fungal-specific cellular response was present in AFS and other EMCRS diseases, different from that associated with fungal allergy, suggesting a nonallergic fungal immune response. Increased CD8+ T cells in EMCRS polyps signify a different type of inflammation to CRS that may be driven by CD8+ T cells.

Eosinophilic fungal rhinosinusitis due to the unusual pathogen Curvularia inaequalis

Among fungi, Curvularia inaequalis is a rare pathogen. We report the first case of non-invasive fungal rhinosinusitis caused by this species. Endoscopic sinus surgery revealed massive polyposis and the presence of viscous eosinophilic mucus that allowed the growth of the fungus. We diagnosed eosinophilic fungal rhinosinusitis based on the histological findings of fungal hyphae in association with degranulating eosinophils in the sinus mucus. After polypectomy and clearance of the affected sinuses, oral itraconazole was administered to prevent the recurrence. Given the ever-increasing list of opportunistic fungi that cause human infection, the case reported here provides further evidence that proper identification of the infective agents remains crucial for the patient's management.

Scottish Thoracic Society Meeting

Introduction: The key pathological features of asthma are eosinophilic airway inflammation, mucus hypersecretion and airway remodelling, mediated by Th2 cytokines (IL-4, IL-5, IL-13). IL-4 or IL-13 administered directly to the airways are sufficient to induce these pathological features independent of antigen (Grunig G et al, Science 1998; Wills-Karp et al, Science 1998). IL-33 is a novel cytokine which binds to the orphan ST2 receptor and induces Th2 cytokine expression (Schmitz et al, Immunity 2005). We hypothesised that IL-33 would be sufficient to induce eosinophilic airway inflammation, and may exacerbate antigen-specific allergic airway inflammation. Methods: The antigen-independent effect of IL-33 was assessed by administering PBS ± recombinant (r)IL-33 intranasally (i.n.) to BALB/c mice for 7 consecutive days. Bronchoalveolar lavage (BAL) was performed 24 h later. Differential cell counts were performed on cytopreps, and the concentration of BAL cytokines and chemokines determined by ELISA. Lungs were obtained for histological assessment. Allergic airway inflammation was induced in BALB/c mice by intraperitoneal (i.p.) sensitisation with ovalbumin (OVA) and alum on day 1, followed by i.n. challenge on days 9 and 11 with OVA ± rIL-33. Mice were analysed as above, and ST2 gene knockout mice were used to demonstrate the specificity of action of rIL-33. Results: rIL-33 induced marked eosinophilic inflammation (fig A). BAL eosinophils (data not shown), cytokines (IL-5 and IL-13, but not IL-4) and chemokines (eotaxin-1, eotaxin-2 and TARC) were increased (table). Airway challenge with OVA following sensitisation induced eosinophilic inflammation, which was increased markedly by rIL-33 (fig B), as were BAL eosinophils, cytokines and chemokines (table). IL-33 had no effect in ST2KO mice in either model. Conclusions: rIL-33 in the absence of antigen induced airway pathology very similar to that of experimental asthma. This was mediated by local induction of Th2 associated cytokines and chemokines, with the exception of IL-4, and was dependent on ST2 expression. In addition, IL-33 exacerbated allergic airway inflammation by a similar mechanism. Thus IL-33/ST2 represents an important mechanism of IL-4-independent airway inflammation, and represents a novel target for therapeutic intervention during both the initiation and maintenance phases of allergic asthma.

Cell-penetrating peptides and proteins: new inhibitors of allergic airways diseaseThis review is an invited paper from 2007 ICRH Leadership in Science: a Forum for Trainees and New Investigators.

Cell-penetrating peptides (CPPs) or protein transduction domains (PTDs) are peptides that have the ability to efficiently traverse cellular membranes, either alone or in association with molecular cargo. Several naturally occurring PTDs, including those from HIV TAT and Drosophila antennapedia, have this unique activity. Synthetic CPPs, such as polyarginine, also have the ability to enter cells and transport a variety of cargo. While the precise mechanism(s) of cellular entry for individual CPPs may vary, it is likely that uptake is mediated, at least in part, through endocytosis. Moreover, biological activity of cell-penetrating peptides and proteins has been clearly demonstrated in a number of in vitro and in vivo studies. Recently, cell-penetrating proteins targeting the Ras GTPase and the phospholipid kinase PI3K (phosphoinositide 3-kinase) have been shown to inhibit eosinophil trafficking and survival in vitro. These proteins, as well as CPPs targeting the STAT-6 transcription factor or the T-cell costimulatory molecule CTLA-4 (cytotoxic T lymphocyte-associated antigen-4), have also been tested in animal models of asthma. Data from several groups, including ours, indicate that these molecules inhibit airway eosinophilic inflammation, airway hyperresponsiveness (AHR), and mucus production in experimental allergic airways disease. Thus, CPPs targeting these and other signaling molecules may also effectively inhibit allergic airways disease in humans.

Human Cathelicidin Antimicrobial Peptide is Up-Regulated in the Eosinophilic Mucus Subgroup of Chronic Rhinosinusitis Patients

Eosinophilic mucus chronic rhinosinusitis (EMCRS) patients are a subgroup of CRS with a poorer prognosis due to frequent recurrences of disease. The cathelicidin antimicrobial peptide (CAMP) is an important innate defense peptide but its role in CRS is not well characterized. The purpose of this study was to investigate CAMP mRNA and protein expression from EMCRS, CRS, and normal control patients. Biopsy specimens of nasal mucosa and nasal polyps were taken from 59 CRS patients and 9 controls. CAMP mRNA and protein levels were analyzed by real-time quantitative reverse-transcriptase polymerase chain reaction, immunoassay, Western blot, and immunohistochemistry. The expression of CAMP mRNA was significantly increased in EMCRS patients compared with CRS patients (p = 0.0004). By immunohistochemistry, expression of CAMP was localized to nasal epithelial, submucosal glands, and inflammatory subepithelial cells. Western blotting confirmed the presence of CAMP in EMCRS, CRS, and control patients. However, we did not detect statistically significant differences in the protein levels in tissue homogenates between EMCRS, CRS, and control patients. This study shows expression of CAMP in nasal mucosa supporting its role in innate defenses against inhaled pathogens. Although CAMP mRNA was up-regulated in EMCRS patients, there were no statistically significant differences in protein levels in the nasal mucosa of EMCRS compared with CRS patients and controls.

Fungal Allergens Induce Cathelicidin LL-37 Expression in Chronic Rhinosinusitis Patients in a Nasal Explant Model

Fungus is thought to play an important role in some subgroups of chronic rhinosinusitis (CRS) patients with eosinophilic mucus (EMCRS). The cathelicidin LL-37 is an important innate defense peptide with antimicrobial activity but its responses in CRS and EMCRS patients have not been established. We investigated the innate immune responses of LL-37 in nasal tissue from CRS and EMCRS patients to fungal allergen challenge. The levels of LL-37 produced by nasal tissue and secreted in response to fungal allergen challenge were determined by a nasal tissue explant in vitro model. LL-37 mRNA and protein levels were quantified by real-time reverse-transcriptase-polymerase chain reaction and immunoassay methods. LL-37 mRNA expression in CRS, but not EMCRS patients, is significantly upregulated by Aspergillus (mean fourfold increase) and Alternaria (mean sixfold increase) extracts in a dose-response manner (p < 0.001). LL-37 peptide levels in the nasal tissue from CRS patients are increased in response to Alternaria (p < 0.05). In contrast, with EMCRS patients, the expression of LL-37 peptide in nasal tissue is increased with Aspergillus (p < 0.001) but is reduced with Alternaria. We also observed a trend where levels of secreted LL-37 were decreased with higher doses of Alternaria and Aspergillus extracts. LL-37 is significantly up-regulated at the mRNA and protein level in CRS patients in response to fungal allergens. However, EMCRS patients do not show increased LL-37 at either the mRNA or the protein level in response to Alternaria.

Surfactant Protein D Expression in Chronic Rhinosinusitis Patients and Immune Responses In Vitro to Aspergillus and Alternaria in a Nasal Explant Model

Common fungi have been implicated in the pathogenesis of chronic rhinosinusitis (CRS) with eosinophilic mucus (EMCRS). Surfactant protein (SP)-D plays an important role in the immune response to Aspergillus fumigatus in the lungs. We sought to determine whether SP-D is expressed in nasal mucosa and investigated the response of SP-D in vitro to fungal allergens. 1) Nasal biopsies from 59 CRS and EMCRS patients, stratified into allergic fungal sinusitis (AFS), nonallergic fungal eosinophilic sinusitis (NAFES), and nonallergic nonfungal eosinophilic sinusitis (NANFES) were studied by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), immunostaining and enzyme-linked immunosorbent assay (ELISA). 2) Nasal tissue from three CRS and three NANFES patients was cultured with fungal allergens in a nasal explant in vitro model for 24 hours at increasing concentrations and mRNA SP-D secreted SP-D protein levels in response to the fungi determined by qRT-PCR and ELISA. Staining for SP-D was detected in the submucosal glands from the nasal biopsies in all patient groups except for AFS. By ELISA, SP-D was undetectable in AFS and decreased in NAFES, NANFES, and CRS compared with controls. CRS patients in vitro cultured with Aspergillus and Alternaria allergens in a nasal tissue explant model induced up-regulation of SP-D by qRT-PCR. In contrast, NANFES nasal tissue explants cultured with Aspergillus allergens induced down-regulation of SP-D. We report for the first time the expression of SP-D in both diseased and normal nasal mucosa. SP-D expression in CRS patients is up-regulated by fungal allergens in an in vitro model. These results may provide potential novel therapy for treatment of CRS.

Eosinophilic Mucus Chronic Rhinosinusitis: Clinical Subgroups or a Homogeneous Pathogenic Entity?

Eosinophilic mucus chronic rhinosinusitis (EMCRS) can be subclassified using the criteria of detection of fungi in eosinophilic mucus and systemic fungal allergy. Allergic fungal sinusitis (AFS), a subgroup of EMCRS characterized by the presence of fungal allergy, is proposed to be an immunoglobulin (Ig)E-driven disease, distinct from other EMCRS subgroups. However, our recent studies cast doubt on the central pathogenic role of allergy in AFS. The purpose of this study was to examine the clinical features of EMCRS patients from the different subcategories to determine the relevance of this classification system. The demographic, clinical, and immunologic characteristics of the EMCRS subgroups were examined prospectively and compared with three control groups: healthy volunteers, allergic rhinitis with fungal allergy, and chronic rhinosinusitis without eosinophilic mucus. EMCRS patients with allergy were younger than those without. There was no significant difference in clinicopathologic parameters between EMCRS subgroups. As a single group, EMCRS had a more severe sinus disease compared with chronic rhinosinusitis patients. AFS was not clinically distinct from other subgroups of EMCRS. However, eosinophilic mucus may mark a more severe and distinct form of sinus disease.

The medical effects of mold exposure

Exposure to molds can cause human disease through several well-defined mechanisms. In addition, many new mold-related illnesses have been hypothesized in recent years that remain largely or completely unproved. Concerns about mold exposure and its effects are so common that all health care providers, particularly allergists and immunologists, are frequently faced with issues regarding these real and asserted mold-related illnesses. The purpose of this position paper is to provide a state-of-the-art review of the role that molds are known to play in human disease, including asthma, allergic rhinitis, allergic bronchopulmonary aspergillosis, sinusitis, and hypersensitivity pneumonitis. In addition, other purported mold-related illnesses and the data that currently exist to support them are carefully reviewed, as are the currently available approaches for the evaluation of both patients and the environment.