title: B-lymphocyte aggregates in alveoli from a child with hypersensitivity pneumonitis (bird breeders lung).
abstract: BACKGROUND
  Hypersensitivity pneumonitis is an interstitial lung disease mediated through a patient's immunologic response to a variety of inhaled organic dusts. Studies of the cellular components of lavage fluid from patients with this disease show marked increases of CD8+ suppressor/cytotoxic T-lymphocytes.
  
  
  OBJECTIVE
  In this study, we identified, in addition to the expected suppressor T-cells and natural killer cells, follicle-like aggregates of B-cells in the lung interstitium of an affected patient.
  
  
  METHODS
  The patient was an 11-year-old non-asthmatic, Caucasian male who presented with a 4-month history of progressive dyspnea, cough, and fever. The home contained nine cockatiel and two doves. Admission pulmonary functions revealed a restrictive pattern with diminished diffusion capacity. Prior to a diagnosis, the patient underwent bronchoalveolar lavage and transbronchial biopsy. Serum precipitins were eventually positive to pigeon (which cross-reacts with dove) droppings. The symptoms resolved after a prolonged course of prednisone.
  
  
  RESULTS
  Analysis of bronchoalveolar lavage lymphocyte population revealed a predominance of CD8+ cells (50%) with 85% expressing the activation marker HLA-DR. The percentage of CD4+ and CD56+ were 32% and 16%, respectively. The transbronchial biopsy revealed CD20+ follicle-like aggregates within the lung interstitium.
  
  
  CONCLUSIONS
  The histopathologic findings confirm that in hypersensitivity pneumonitis, the predominant immune response is an infiltrate of CD8+ T cells. The presence of B cell aggregates, however, may indicate that the local synthesis of antibody may be involved in an antibody-dependent cellular cytotoxic mechanism.
authors.affiliation: Department of Pediatrics, St. Louis University School of Medicine, Missouri, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: McClellan
authors.forename: G M
authors.initials: GM
authors.lastname: Albers
authors.forename: B E
authors.initials: BE
authors.lastname: Noyes
authors.forename: C
authors.initials: C
authors.lastname: Sotelo
authors.forename: J A
authors.initials: JA
authors.lastname: Petterchak
authors.forename: A P
authors.initials: AP
authors.lastname: Knutsen
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001716:Bird Fancier's Lung / Q000175:diagnosis / Q000276:immunology*; D001717:Birds / Q000276:immunology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D002648:Child; D006801:Humans; D008297:Male; D011650:Pulmonary Alveoli / Q000276:immunology*