title: CD4/CD8 lymphocytes in BALF during the efferent phase of lung delayed-type hypersensitivity reaction induced by single antigen inhalation.
abstract: BACKGROUND
  The precise mechanisms involved in the pathogenesis of hypersensitivity pneumonitis (HP) have not been identified. HP is characterized by inflammatory lymphocytic alveolitis and a remarkable increase in T-lymphocytes detected in bronchoalveolar lavage fluid (BALF). It is suggested that both CD4+ and CD8+ T cells may contribute to the pathogenesis of HP. Experiments on animal models suggest that cell mediated immunity (CMI) is more important for the pathogenesis of HP than complex-mediated immunity, but the relationship between the subsets of BALF lymphocytes and humoral or cell-mediated allergic reactions is still not clear. The aim of our study was distinguish CD4+ and CD8+ T cells in BALF lymphocytes during a delayed-type hypersensitivity (DTH) reaction in the lung.
  
  
  METHODS
  The experiment was performed on guinea pigs sensitized with BCG vaccine and subjected to a single inhalation of tubercle bacilli antigens (tuberculin). 24 hours after tuberculin provocation (at the time of maximum lymphocyte infiltration), bronchoalveolar lavage was performed on both sensitized and non-sensitized (control) animals. The total cell count was estimated, and a differential microscopical examination of BAL-fluid cells was performed, along with the phenotyping of BALF lymphocytes (by flow cytometry).
  
  
  RESULTS
  In the BALF of the sensitized animals, as compared to the controls, there was a statistically significant increase in the percentage and absolute count of T-lymphocytes, CD4+ and CD8+. The CD4 / CD8 ratio in both groups did not differ significantly and was individually variable (2.94I0.72 SEM in the experimental group, vs 4.41I1.29 SEM in the control group).
  
  
  CONCLUSIONS
  Both CD4+ and CD8+ lymphocytes (with some predominance of helper cells) participate in the efferent phase of the delayed type hypersensitivity reaction in the lung induced by antigen inhalation.
authors.affiliation: Department and Clinic of Internal Medicine, Pulmonology and Allergology, Medical University, Warsaw, Poland. hgj@amwaw.edu.pl
authors.forename: H
authors.initials: H
authors.lastname: Grubek-Jaworska
authors.forename: G
authors.initials: G
authors.lastname: Hoser
authors.forename: P
authors.initials: P
authors.lastname: Droszcz
authors.forename: R
authors.initials: R
authors.lastname: Chazan
mesh_terms: D000818:Animals; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D006168:Guinea Pigs; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D008168:Lung / Q000276:immunology* / Q000502:physiology; D008297:Male; D014373:Tuberculin / Q000008:administration & dosage / Q000276:immunology
chemical_list: D014373:Tuberculin