title: New insights into pediatric idiopathic pulmonary hemosiderosis: the French RespiRare(®) cohort.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Pediatric Pulmonary Department, AP-HP, Hôpital Trousseau, Université Pierre et Marie Curie-Paris6, Inserm U938, 26, avenue du Docteur Arnold-Netter, 75012 Paris, France. harriet.corvol@trs.aphp.fr.
authors.forename: Jessica
authors.initials: J
authors.lastname: Taytard
authors.forename: Nadia
authors.initials: N
authors.lastname: Nathan
authors.forename: Jacques
authors.initials: J
authors.lastname: de Blic
authors.forename: Mickael
authors.initials: M
authors.lastname: Fayon
authors.forename: Ralph
authors.initials: R
authors.lastname: Epaud
authors.forename: Antoine
authors.initials: A
authors.lastname: Deschildre
authors.forename: Françoise
authors.initials: F
authors.lastname: Troussier
authors.forename: Marc
authors.initials: M
authors.lastname: Lubrano
authors.forename: Raphaël
authors.initials: R
authors.lastname: Chiron
authors.forename: Philippe
authors.initials: P
authors.lastname: Reix
authors.forename: Pierrick
authors.initials: P
authors.lastname: Cros
authors.forename: Malika
authors.initials: M
authors.lastname: Mahloul
authors.forename: Delphine
authors.initials: D
authors.lastname: Michon
authors.forename: Annick
authors.initials: A
authors.lastname: Clement
authors.forename: Harriet
authors.initials: H
authors.lastname: Corvol
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006486:Hemosiderosis / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007223:Infant; D008171:Lung Diseases / Q000175:diagnosis* / Q000188:drug therapy; D008297:Male; D000097545:Hemosiderosis, Pulmonary
chemical_list: D007166:Immunosuppressive Agents