title: Immunophenotyping and protein profiling of Fontan-associated plastic bronchitis airway casts.
abstract: BACKGROUND
  Plastic bronchitis (PB) is a rare and deadly condition that is characterized by the formation of airway casts. It most frequently occurs in children with underlying congenital heart disease that has been surgically palliated by the Fontan procedure. The Fontan circulation results in above-normal central venous pressure, and it has been hypothesized that the formation of airway casts is due to lymph leak. Knowledge of plastic bronchitis pathogenesis is poor and stems mostly from published case reports.
  
  
  OBJECTIVE
  To garner information about cast pathogenesis by characterizing inflammatory cell phenotypes in existing formalin-preserved, paraffin-embedded samples and generating protein and cytokine-chemokine profiles of airway cast homogenates.
  
  
  METHODS
  We used immunofluorescence confocal microscopy, state-of-the-science proteomics, and a cytokine array assay to immunophenotype cellular content and to generate protein and cytokine profiles of plastic bronchitis airway casts, respectively.
  
  
  RESULTS
  Neutrophils, eosinophils, macrophages, and B lymphocytes were identified in cast samples; there were notably fewer T lymphocytes. Fibrin(ogen) was an abundant protein in the cast proteome. Histone H4 was also abundant, and immunofluorescence microscopy demonstrated it to be mostly extracellular. The cytokine profile of plastic bronchitis casts was proinflammatory.
  
  
  CONCLUSIONS
  Plastic bronchitis airway casts from children with Fontan physiology are composed of fibrin and are cellular and inflammatory in nature, providing evidence that their formation cannot be explained simply by lymph leak into the airways. Consequences of cellular necrosis including extracellular histones and the apparent low number of T cells indicate that a derangement in inflammation resolution likely contributes to cast formation.
authors.affiliation: Department of Clinical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Racz
authors.forename: Gerta
authors.initials: G
authors.lastname: Mane
authors.forename: Michael
authors.initials: M
authors.lastname: Ford
authors.forename: Lindsay
authors.initials: L
authors.lastname: Schmidt
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Myers
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Standiford
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Schumacher
authors.forename: Carlen
authors.initials: C
authors.lastname: Fifer
authors.forename: Mark W
authors.initials: MW
authors.lastname: Russell
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Stringer
mesh_terms: D001991:Bronchitis / Q000209:etiology / Q000276:immunology* / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D001999:Bronchoscopy; D002648:Child; D016207:Cytokines / Q000032:analysis*; D005337:Fibrin / Q000032:analysis*; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000601:surgery; D006657:Histones / Q000032:analysis*; D006801:Humans; D007111:Immunity, Cellular; D016130:Immunophenotyping / Q000379:methods*; D040901:Proteomics / Q000379:methods
chemical_list: D016207:Cytokines; D006657:Histones; D005337:Fibrin