Background: Idiopathic pulmonary hemosiderosis (IPH) is a rare cause of alveolar hemorrhage in children and its pathophysiology remains obscure. Classically, diagnosis is based on a triad including hemoptysis, diffuse parenchymal infiltrates on chest X-rays, and iron-deficiency anemia. We present the French pediatric cohort of IPH collected through the French Reference Center for Rare Lung Diseases (RespiRare®,http://www.respirare.fr).Methods: Since 2008, a national network/web-linked RespiRare® database has been set up in 12 French pediatric respiratory centres. It is structured as a medical recording tool with extended disease-specific datasets containing clinical information relevant to all forms of rare lung diseases including IPH.Results: We identified 25 reported cases of IPH in children from the database (20 females and 5 males). Among them, 5 presented with Down syndrome. Upon diagnosis, median age was 4.3 [0.8-14.0] yrs, and the main manifestations were: dyspnea (n = 17, 68%), anemia (n = 16, 64%), cough (n = 12, 48%), febrile pneumonia (n = 11, 44%) and hemoptysis (n = 11, 44%). Half of the patients demonstrated diffuse parenchymal infiltrates on chest imaging, and diagnosis was ascertained either by broncho-alveolar lavage indicating the presence of hemosiderin-laden macrophages (19/25 cases), or lung biopsy (6/25). In screened patients, initial auto-immune screening revealed positive antineutrophilic cytoplasmic antibodies (ANCA) (n = 6, 40%), antinuclear antibodies (ANA) (n = 5, 45%) and specific coeliac disease antibodies (n = 4, 28%). All the patients were initially treated by corticosteroids. In 13 cases, immunosuppressants were introduced due to corticoresistance and/or major side effects. Median length of follow-up was 5.5 yrs, with a satisfactory respiratory outcome in 23/25 patients. One patient developed severe pulmonary fibrosis, and another with Down syndrome died as a result of severe pulmonary hemorrhage.Conclusion: The present cohort provides substantial information on clinical expression and outcomes of pediatric IPH. Analysis of potential contributors supports a role of auto-immunity in disease development and highlights the importance of genetic factors.

In recent years, the gut microbiota has been considered as a full-fledged actor of the gut–brain axis, making it possible to take a new step in understanding the pathophysiology of both neurological and psychiatric diseases. However, most of the studies have been devoted to gut bacterial microbiota, forgetting the non-negligible fungal flora. In this review, we expose how the role of the fungal component in the microbiota-gut-brain axis is legitimate, through its interactions with both the host, especially with the immune system, and the gut bacteria. We also discuss published data that already attest to a role of the mycobiome in the microbiota-gut-brain axis, and the impact of fungi on clinical and therapeutic research.

Interstitial lung diseases (ILDs) in children represent a heterogeneous group of rare respiratory disorders that affect the lung parenchyma. After the launch of the French Reference Centre for Rare Lung Diseases (RespiRare®), we created a national network and a web-linked database to collect data on pediatric ILD.

Cystic fibrosis (CF) is a systemic genetic disease that leads to pulmonary and digestive disorders. In the majority of CF patients, the intestine is the site of chronic inflammation and microbiota disturbances. The link between gut inflammation and microbiota dysbiosis is still poorly understood. The main objective of this study was to assess gut microbiota composition in CF children depending on their intestinal inflammation. We collected fecal samples from 20 children with CF. Fecal calprotectin levels were measured and fecal microbiota was analyzed by 16S rRNA sequencing. We observed intestinal inflammation was associated with microbiota disturbances characterized mainly by increased abundances of Staphylococcus, Streptococcus, and Veillonella dispar, along with decreased abundances of Bacteroides, Bifidobacterium adolescentis, and Faecalibacterium prausnitzii. Those changes exhibited similarities with that of Crohn’s disease (CD), as evidenced by the elevated CD Microbial-Dysbiosis index that we applied for the first time in CF. Furthermore, the significant over-representation of Streptococcus in children with intestinal inflammation appears to be specific to CF and raises the issue of gut–lung axis involvement. Taken together, our results provide new arguments to link gut microbiota and intestinal inflammation in CF and suggest the key role of the gut–lung axis in the CF evolution.