Fungus and chronic rhinosinusitis: weighing the evidence

Detection of Candida albicans-Specific CD4+ and CD8+ T Cells in the Blood and Nasal Mucosa of Patients with Chronic Rhinosinusitis

Candida albicans is ubiquitously present, and colonization in the nose and oral cavity is common. In healthy patients, it usually does not act as a pathogen, but in some cases can cause diseases. The influence of C. albicans as a trigger of T cell activation on the pathogenesis of chronic rhinosinusitis (CRS) is controversial, and its exact role is not clear to date. The aim of the present study was to detect and characterize C. albicans-specific CD4+ and CD8+ T cells in patients with CRS, with and without nasal polyps. Tissue and blood samples were collected from patients suffering from chronic rhinosinusitis with (CRSwNP) and without nasal polyps (CRSsNP), and from healthy controls. A peptide pool derived from C. albicans antigen was added to tissue and blood samples. After 6 days, lymphocytes were analyzed by multicolor flow cytometry. Activation was assessed by the intracellular marker Ki-67, and the cytokine secretion was measured. Tissue CD8+ T cells of CRSsNP patients showed a significantly higher proportion of Ki-67+ cells after activation with C. albicans antigen compared to peripheral blood CD8+ T cells. Cytokine secretion in response to C. albicans antigen was similar for all study groups. In this study, C. albicans-specific CD4+ and CD8+ T cells were detected in peripheral blood and mucosal tissue in all study groups. In patients suffering from CRSsNP, C. albicans-specific CD8+ T cells were relatively enriched in the nasal mucosa, suggesting that they might play a role in the pathogenesis of CRSsNP.

Fungal Rhinosinusitis: Prevalence and Spectrum in Singapore

Background

Fungal involvement of the paranasal sinuses has been described more than two centuries ago. In the current article, it is referred to as fungal rhinosinusitis (FRS) which is a general term that is used to describe a spectrum of pathologically, immunologically, and clinically different disease entities affecting the paranasal sinuses where fungus is thought to be the major potential etiology.

Objective

To determine the incidence and spectrum of FRS in Singapore and to compare our findings with international figures through literature review.

Methods

A retrospective review of the clinical charts, radiological and laboratory results, and operative reports of all patients who underwent endoscopic sinus surgery at an ENT department of a tertiary referral hospital in Singapore over five-year period.

Results

Out of 533 functional endoscopic sinus surgeries performed during the period of the study for management of chronic rhinosinusitis, 44 (8.4%) were found to fit the criteria for diagnosis of FRS. Twenty (45.5%) were eosinophilic FRS and 24 (54.5%) were fungal balls. Invasive FRS has not been encountered. Clinical presentation, investigations, and management of both groups of patients are discussed.

Conclusion

Fungal rhinosinusitis is not uncommon in Singapore. Fungal ball and eosinophilic mucin fungal rhinosinusitis are among the most common forms encountered in this part of the world.

Fungal Microbiota in Chronic Airway Inflammatory Disease and Emerging Relationships with the Host Immune Response

The respiratory tract is a complex system that is inhabited by niche-specific communities of microbes including bacteria, fungi, and viruses. These complex microbial assemblages are in constant contact with the mucosal immune system and play a critical role in airway health and immune homeostasis. Changes in the composition and diversity of airway microbiota are frequently observed in patients with chronic inflammatory diseases including chronic rhinosinusitis (CRS), cystic fibrosis, allergy, and asthma. While the bacterial microbiome of the upper and lower airways has been the focus of many recent studies, the contribution of fungal microbiota to inflammation is an emerging research interest. Within the context of allergic airway disease, fungal products are important allergens and fungi are potent inducers of inflammation. In addition, murine models have provided experimental evidence that fungal microbiota in peripheral organs, notably the gastrointestinal (GI) tract, influence pulmonary health. In this review, we explore the role of the respiratory and GI microbial communities in chronic airway inflammatory disease development with a specific focus on fungal microbiome interactions with the airway immune system and fungal-bacterial interactions that likely contribute to inflammatory disease. These findings are discussed in the context of clinical and immunological features of fungal-mediated disease in CRS, allergy, and asthmatic patients. While this field is still nascent, emerging evidence suggests that dysbiotic fungal and bacterial microbiota interact to drive or exacerbate chronic airway inflammatory disease.

Allergic Aspergillus Rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) is a unique variety of chronic polypoid rhinosinusitis usually in atopic individuals, characterized by presence of eosinophilic mucin and fungal hyphae in paranasal sinuses without invasion into surrounding mucosa. It has emerged as an important disease involving a large population across the world with geographic variation in incidence and epidemiology. The disease is surrounded by controversies regarding its definition and etiopathogenesis. A working group on "Fungal Sinusitis" under the International Society for Human and Animal Mycology (ISHAM) addressed some of those issues, but many questions remain unanswered. The descriptions of "eosinophilic fungal rhinosinusitis" (EFRS), "eosinophilic mucin rhinosinusitis" (EMRS) and mucosal invasion by hyphae in few patients have increased the problem to delineate the disease. Various hypotheses exist for etiopathogenesis of AFRS with considerable overlap, though recent extensive studies have made certain in depth understanding. The diagnosis of AFRS is a multi-disciplinary approach including the imaging, histopathology, mycology and immunological investigations. Though there is no uniform management protocol for AFRS, surgical clearing of the sinuses with steroid therapy are commonly practiced. The role of antifungal agents, leukotriene antagonists and immunomodulators is still questionable. The present review covers the controversies, recent advances in pathogenesis, diagnosis, and management of AFRS.

P-glycoprotein regulates Staphylococcus aureus enterotoxin B-stimulated interleukin-5 and thymic stromal lymphopoietin secretion in organotypic mucosal explants

BACKGROUND

T-helper 2 (Th2) inflammation is a hallmark of chronic rhinosinusitis with nasal polyps (CRSwNP) although the pathogenesis is poorly understood. P-glycoprotein (permeability glycoprotein, P-gp) is an efflux pump that is capable of regulating cytokine transport and is expressed within sinonasal mucosa. The purpose of this study was to examine if the oversecretion of interleukin 5 (IL-5) and thymic stromal lymphopoietin (TSLP) in CRSwNP could be explained through P-gp-mediated secretory pathways.

METHODS

Fifteen ethmoid mucosal explants were harvested from patients with CRS (n = 10) and CRSwNP (n = 10) and stimulated with Staphylococcus aureus enterotoxin B (SEB). P-gp was inhibited using zosuquidar trihydrochloride (herein Zosuquidar). P-gp expression was measured using real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-5, IL-8, and TSLP secretion were quantified using ELISA.

RESULTS

P-gp protein was overexpressed in CRSwNP (28.32 ± 25.94 ng/mL per mg explant) as compared to CRS (10.74 ± 8.61; p = 0.01, 2-tailed Mann-Whitney U test). There was no difference in messenger RNA (mRNA) expression. SEB induced a significant increase in IL-5 and TSLP but not IL-8 secretion relative to control in the CRSwNP explants only. Subsequent P-gp inhibition significantly reduced IL-5 and TSLP secretion (p = 0.04 for both, 2-tailed Student t test) to control levels. The concentration of IL-5 and TSLP secretion were strongly and significantly correlated to the concentration of P-gp within the same explant (IL-5: r = 0.791, p = 0.001; TSLP: r = 0.687, p = 0.003; 2-tailed Spearman's rank-order correlation).

CONCLUSION

P-gp protein is expressed at higher concentrations in CRSwNP as compared to CRS. This overexpression directly contributes to the relative hypersecretion of IL-5 and TSLP. These findings suggest a novel mechanism for Th2 skewing in CRSwNP.

Damage-associated molecular patterns stimulate interleukin-33 expression in nasal polyp epithelial cells

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a disorder characterized by eosinophilic inflammation and local T-helper 2 (Th2) cytokine production. Innate lymphoid cells that elaborate Th2 cytokines have recently been characterized within nasal polyps. These cells can be activated by the epithelial cell-derived cytokine interleukin-33 (IL-33). The objective of this study is to determine whether 2 molecules associated with tissue damage (high mobility group box-1 [HMGB-1] and adenosine triphosphate [ATP]) elicit expression of IL-33 in sinonasal epithelial cells (SNECs) derived from recalcitrant CRSwNP patients.

METHODS

Ethmoid tissue was obtained from 8 recalcitrant CRSwNP and 9 control subjects during endoscopic sinus surgery (ESS). Tissue was prepared for immunohistochemistry and for SNEC air-liquid interface culture. After exposure to either HMGB1 or ATP in vitro, SNECs were processed for messenger RNA (mRNA) extraction and immunocytochemistry. IL-33 levels were determined by real-time polymerase chain reaction (PCR) and by immunochemical staining with anti-IL-33 antibody.

RESULTS

Intranuclear IL-33 is normally expressed in basal epithelial cells, but is present in more apical cells and outside the nucleus in CRSwNP. Exposure of SNECs to HMGB-1 or ATP resulted in a statistically significant increase in IL-33 mRNA expression in SNECs derived from recalcitrant CRSwNP patients. This increase was reflected at the protein level by immunochemical staining of IL-33.

CONCLUSION

Tissue damage is a nonspecific trigger of epithelial IL-33 production in treatment-recalcitrant polyps, which may be responsible for perpetuating eosinophilic inflammation in CRSwNP. This common pathway may help explain why multiple environmental and infectious agents have been implicated in CRSwNP exacerbation.

Respiratory allergy to airborne fungi in São Luís--MA: clinical aspects and levels of IgE in a structured asthma program

INTRODUCTION

Respiratory allergies are becoming increasingly frequent, especially based on studies of asthma and rhinitis. It is estimated that 20-30% of the world's population is affected. Allergic reactions are caused by the production of IgE antibodies specific to inhaled allergens, such as fungi in the air. This study aimed to analyze the level of specific IgE against airborne fungi in patients with a clinical diagnosis of asthma and rhinitis/sinusitis.

METHODS

In total, 158 patients enrolled in the Program of Support for Asthmatic Patient, and 20 controls were studied. Clinical data from the period of 2007-2008 were surveyed using a protocol form. ELISAs were performed to quantify the levels of total and specific IgE.

RESULTS

Of the 158 patients diagnosed with asthma, 71 had rhinitis and 32 had sinusitis. There was a predominance of females and residents of urban areas. The main symptoms reported were dyspnea, cough, wheezing and nasal obstruction. There was a statistically significant relationship between dyspnea and seropositivity for Fusarium (p = 0.01) and Penicillium (p = 0.005) and between cough and seropositivity for Aspergillus (p = 0.007).

CONCLUSIONS

Anti-Penicillium (79.7%) and anti-Fusarium IgE (77.8%) were found to have the highest prevalence of seropositivity in individuals with asthma and rhinitis/sinusitis. Sensitivity to fungi was higher in symptomatic individuals. The identification of environmental fungi is essential for the diagnosis of respiratory allergy.

Endotypes and phenotypes of chronic rhinosinusitis: a PRACTALL document of the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma & Immunology

Chronic rhinosinusitis (CRS) is a complex disease consisting of several disease variants with different underlying pathophysiologies. Limited knowledge of the mechanisms of these disease subgroups is possibly the greatest obstacle in understanding the causes of CRS and improving treatment. It is generally agreed that there are clinically relevant CRS phenotypes defined by an observable characteristic or trait, such as the presence or absence of nasal polyps. Defining the phenotype of the patient is useful in making therapeutic decisions. However, clinical phenotypes do not provide full insight into all underlying cellular and molecular pathophysiologic mechanisms of CRS. Recognition of the heterogeneity of CRS has promoted the concept that CRS consists of multiple groups of biological subtypes, or "endotypes," which are defined by distinct pathophysiologic mechanisms that might be identified by corresponding biomarkers. Different CRS endotypes can be characterized by differences in responsiveness to different treatments, including topical intranasal corticosteroids and biological agents, such as anti-IL-5 and anti-IgE mAb, and can be based on different biomarkers that are linked to underlying mechanisms. CRS has been regarded as a single disease entity in clinical and genetic studies in the past, which can explain the failure to identify consistent genetic and environmental correlations. In addition, better identification of endotypes might permit individualization of therapy that can be targeted against the pathophysiologic processes of a patient's endotype, with potential for more effective treatment and better patient outcomes.

Respiratory allergy to fungi in Barcelona, Spain: clinical aspects, diagnosis and specific treatment in a general allergy unit

BACKGROUND

The importance of hypersensitivity to fungal allergens is a relatively unknown and somewhat controversial subject.

METHODS

An open prospective study was carried out in just one centre to determine the clinical and epidemiological characteristics as well as the diagnostic usefulness of skin prick and conjunctiva provocation tests, associated with total and specific IgE determination in two groups of patients, one of which was monosensitised to fungi and the other of which had multiple sensitisations, including fungi.

RESULTS

Rhinitis, exclusive or associated with asthma, was the main consultation cause (88% in monosensitised patients). Severe asthma was rarely found. In the polysensitised group, 64% were simultaneously allergic to moulds and mites. Alternaria alternata was the most common sensitising fungus, although a considerable number of cases were associated with other species such as Cladosporium, Penicillium and/or Aspergillus. The skin prick test gave the highest sensitivity and specificity. In 67% of the cases, the specific IgE was found between classes 3 and 4. The conjunctival provocation test was an innocuous and highly useful method for verifying the diagnosis and determining the degree of clinical sensitisation. A large number of patients exclusively allergic to fungi received specific immunotherapy, and it was generally well tolerated.

CONCLUSIONS

This protocolised study shows the importance of Alternaria and other fungi sensitisations in rhinitis alone or associated with asthma. Combined diagnosis of prick test, specific IgE and conjunctiva provocation test is very useful for deciding specific immunotherapy.

Role of fungi in pathogenesis of chronic rhinosinusitis: the hypothesis rejected

PURPOSE OF REVIEW

Fungi have been suggested to play an important role in the pathogenesis of chronic rhinosinusitis (CRS). This review describes the recent knowledge concerning the role of fungi in the pathogenesis of CRS and allergic fungal rhinosinusitis (AFRS) and the clinical implications for treatment.

RECENT FINDINGS

Recent studies show that, although there are several potential deficits in the innate and potentially also in the acquired immunity of CRS patients that might reduce or change their ability to react to fungi, there are not many arguments to suggest a causative role for fungi in CRS with or without nasal polyps. However, due to the intrinsic or induced change in immunity of CRS patients, fungi might have a disease-modifying role. The fact that AFRS is more prevalent in warm and humid areas may point to fungi as a factor in this disease.

SUMMARY

Almost a decade after the launching of the hypothesis by Ponikau, the absence of convincing immunological data or evidence for clinical improvement of CRS upon therapy with antifungal agents now means that the hypothesis that fungi play a role in a majority of the cases of CRS has to be rejected and antifungal treatment should not be used.