Investigation of fungi in massive nasal polyps: microscopy, culture, polymerase-chain reaction, and serology

An overview of possible pathogenesis mechanisms of Alternaria alternata in chronic rhinosinusitis and nasal polyposis

Chronic Rhinosinusitis (CRS) is a multifactorial disease, and different etiologies like metabolism and immunity disorders, bacterial superantigens, biofilms, and fungal allergens are known to develop this disease, especially the CRS with nasal polyps. Alternaria alternata (Alternaria) is one of the most prevalent airborne fungal species in the nasal discharge, which might have vigorous immunologic activities in nasal epithelial cells and play an essential role in the pathogenesis of CRS. Moreover, the interaction between this fungus and the innate and adaptive immune systems leads to the development of chronic inflammation. This inflammation may consequently instigate the CRS and nasal polyposis. The attenuation of surfactant protein synthesis or intracellular reserves and mucus hypersecretion could prevent the clearance of Alternaria from sinuses and may be correlated with colonization and re-infection of airborne fungi. Furthermore, higher expression of cathelicidin, thymic stromal lymphopoietin, toll-like receptors, and T helper 2-dominant immune responses can result in an IgE-mediated pathway activation and eosinophils degranulation. Moreover, higher local Alternaria-specific IgE was shown to be correlated with eosinophilic cationic proteins and might relate to nasal polyps. However, the role of genetic and environmental factors affecting CRS and nasal polyposis is not well studied. Likewise, further animal and clinical studies are required to better understand the role of Alternaria in CRS disease. The current article reviews the recent findings around the Alternaria-induced CRS and nasal polyposis.

Role of TLRs in the production of chemical mediators in nasal polyp fibroblasts by fungi

OBJECTIVE

Fibroblasts are major supporting cells in nasal mucosa and can induce inflammatory process with recruitment of inflammatory cells. Airborne fungi have been suggested as an etiologic factor of chronic rhinosinusitis (CRS). The aim of this study was to investigate the interaction between airborne fungi and pattern recognition receptors (PRRs) in nasal fibroblasts.

METHODS

Primary nasal polyp fibroblasts were cultured with Alternaria and Aspergillus for 48h. To determine the production of chemical mediators interleukine-6 (IL-6), IL-8, granulocyte-macrophage colony stimulating factor (GM-CSF), eotaxin, and regulated on activation normal T expressed and secreted (RANTES) were measured with enzyme immunoassay methods. PRRs for toll-like receptors (TLRs) and protease-activated receptors (PARs) mRNA were determined with reverse transcription polymerase chain reaction (RT-PCR). To determine the role of PRRs, fibroblasts were treated with small interfering RNA (siRNA).

RESULTS

IL-6 and IL-8 productions were significantly increased by 50 and 100μg/ml of Alternaria. However, GM-CSF, eotaxin, and RANTES productions did not change. Aspergillus did not influence the production of chemical mediators from nasal polyp fibroblasts. TLR2 and TLR5 mRNA expressions were significantly increased by fungi and these two TLRs were associated with the production of IL-6 and IL-8.

CONCLUSION

Alternaria interacts as a pathogen-associated molecular pattern with the PRRs, such as TLR2 and TLR5, which induce the production of inflammatory chemical mediators from nasal polyp fibroblasts. Airborne fungi enhance the innate immune defense mechanism and may be associated with the pathogenesis of nasal inflammatory diseases.

Nasal polyposis and fungal Schizophyllum commune infection: a case report

We present a rare case of eosinophilic fungal rhinosinusitis with nasal polyps in a 32-year-old woman caused by basidiomycete fungus Schizophyllum commune. Diagnosis was done by the endoscopic nasal examination, computed tomography (CT) of the paranasal sinuses, the histopathological examination of polyps, the presence of eosinophils and fungal hyphae in nasal mucus and by the detection of S. commune by culture. The patient was successfully treated by combination of oral itraconazole and topical corticosteroid therapy combined with surgery. The pathogenesis and diagnosis of allergic fungal rhinosinusitis are also discussed.

Fungus as the cause of chronic rhinosinusitis: the case remains unproven

PURPOSE OF REVIEW

To review the literature on the role of fungi in chronic rhinosinusitis (CRS) pathogenesis and the effect of antifungal drug therapy and antifungal immunotherapy.

RECENT FINDINGS

This paper reviews the most recent articles investigating the role of fungi in CRS pathogenesis. In addition to possible aberrant innate and adaptive antifungal immune responses and fungus antihost effects, which all may explain disease development, the effect of antifungal drug therapy and antifungal immunotherapy is reviewed.

SUMMARY

Although fungi can be detected in the nose and paranasal sinuses of nearly all patients with CRS and are present in almost all healthy controls, various studies suggest that there may be mechanisms by which fungi exert an effect on sinus mucosa in susceptible individuals only. Future studies will have to clarify the role of fungi in CRS, which fungal organisms, if at all, may be pathogenic and what exactly characterizes the immunological response to fungi that potentially results in the development of disease. Presently, in the absence of convincing immunological data and evidence for clinical improvement of CRS upon therapy with antifungal agents, the case against the fungus remains unproven.

The mold conundrum in chronic hyperplastic sinusitis

The role of fungi in chronic rhinosinusitis (CRS) is not clear. Fungi can be detected in the nose and paranasal sinuses of virtually all CRS patients; however, they also appear to be present in healthy controls. Various theories attempt to explain the mechanisms by which fungi can exert an effect on sinus mucosa in susceptible individuals. Further studies are necessary to clarify the role of fungi in CRS, which fungal organisms (if any) are pathogenic, and what exactly characterizes the immunologic response to fungi that may result in the development of disease. However, in the absence of convincing immunologic data and evidence of clinical improvement of CRS after antifungal therapy, the case against the fungus remains unproven.

Diagnosis of clinically relevant fungi in medicine and veterinary sciences

This review focuses on the most economically and epidemiologically important fungi affecting humans and animals. This paper will also summarize the different techniques, either molecular, based on nucleic acid and antibody analysis, or nonmolecular such as microscopy, culture, UV Wood's lamp, radiology, and spectroscopy used to identify species or group of fungi assisting clinicians to take the best control approach to clear such infections. On the molecular side, the paper will review results on genome sequencing which can help colleagues to identify their own DNA/RNA tests if they are interested in the diagnostic of fungi in medicine and veterinary medicine.