About this Research Topic
Cystic fibrosis (CF), the main inherited genetic disease in the European Caucasian population, results from mutations in the CFTR (Cystic Fibrosis Transmembrane conductance Regulator) gene that encodes a membrane transporter involved in electrolytic exchanges across the apical membrane of many epithelial cell types. Various organs are affected by the dysfunction of this membrane transporter, but prognosis essentially depends on the lesions of the lungs. Indeed, the respiratory tract of CF patients is frequently colonized by microorganisms, leading to respiratory infections which are the main cause of morbidity and mortality.
In the respiratory tract, mutations in the CFTR gene result in thickening of the bronchial mucus and impairment of the mucociliary clearance that allows the entrapment of the inhaled fungal bacteria and fungal spores and provides a favorable environment for the growth of microorganisms. As bacteria, especially Pseudomonas aeruginosa, are the major cause of these infections, special attention has been paid to the prevention and treatment of bacterial infections in recent decades. Progress in this field, together with the development of the early diagnosis of the disease and improvement in the nutritional status of the patients, has led to a significant increase in life expectancy. However, alongside bacteria, many fungal species can also colonize patient airways, sometimes leading to respiratory infections whose frequency regularly increased along with the increase in life expectancy. However, unlike bacterial infections, little is known today about the epidemiology and pathogenesis of fungal infections.
Candida albicans for yeasts and Aspergillus fumigatus for filamentous fungi are the most common species in the CF airways. However, other fungi are increasingly reported in this context, such as Scedosporium species, Aspergillus terreus, Exophiala dermatitidis, species of the Rasamsonia argillacea complex or Lomentospora prolificans. In addition, pioneering studies of the microbiota have suggested an even greater diversity of the fungal biota colonizing the CF airways.
Apart from A. fumigatus, the prevalence of filamentous fungi in CF is certainly underestimated due to the lack of standardization of the procedures used for mycological examination of the respiratory secretions. Likewise, the clinical significance of their isolation remains to be clarified. Nevertheless, recent studies on Aspergillus fumigatus or Candida albicans show that the chronic colonization of the airways by fungi contributes to the clinical or functional deterioration. In addition, because of their ability to disseminate in a susceptible host and their usual low susceptibility to antifungals, these fungi can cause severe disseminated infections in immunocompromised patients, especially in previously colonized patients undergoing lung or heart/lung transplantation.
In this Research Topic, we welcome the submission of Original Research, Review and Opinion articles, Methods, and Case Reports covering recent advances in our understanding of fungal infections in cystic fibrosis. Papers should be focused on aspects such as: (i) epidemiology and pathogenesis of these infections; (ii) immune response against these fungi; (iii) ecology of these fungi and mode of contamination of the patients; (iv) host-fungus interactions and fungal pathogenic factors; (v) diagnostic tools; and (vi) innovative treatments.
Keywords: Fungi, Airways, Cystic Fibrosis, Pathogenicity, Immune Response
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