T-cell phenotypes in bronchoalveolar lavage fluid, blood and lymph nodes in pulmonary sarcoidosis--indication for an airborne antigen as the triggering factor in sarcoidosis

J Intern Med. 2012 Nov;272(5):465-71. doi: 10.1111/j.1365-2796.2012.02543.x. Epub 2012 May 12.


Background: An increased percentage of CD4+ T cells is usually observed in bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis. In HLA-DRB1*03-positive patients, such T cells express the T-cell receptor (TCR) AV2S3+ gene segment. It is not known whether cells found in BALF reflect those in enlarged regional lymph nodes (LNs). Therefore, the aim of this study was to compare T-cell phenotypes in BALF, blood and mediastinal LNs.

Methods: Fifteen patients underwent clinical investigation including bronchoscopy with bronchoalveolar lavage. Blood samples were drawn, and endoscopic ultrasound-guided fine-needle aspiration of enlarged mediastinal LNs was performed via the oesophagus. T cells from all three compartments were analysed by flow cytometry for markers of activity, differentiation and T regulatory function.

Results: The CD4/CD8 ratio was significantly higher in BALF compared with regional LNs and was also significantly higher in LNs than in blood. The CD4+ T cells were recently activated and more differentiated in BALF than in blood and LNs. There was an accumulation of T regulatory cells (FOXP3+) in LNs and a correlation between high levels of FOXP3+ cells in BALF and in LNs. In HLA-DRB1*03-positive patients, TCR AV2S3+ CD4+ T cells were predominantly localized within BALF.

Conclusions: The CD4+ T-cell phenotype in BALF indicates an active ongoing specific immune response primarily localized to the alveolar space.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antigens / genetics
  • Antigens / immunology
  • Bronchoalveolar Lavage Fluid / immunology*
  • Bronchoscopy / methods
  • CD4-Positive T-Lymphocytes / immunology*
  • Case-Control Studies
  • Female
  • Humans
  • Immunophenotyping
  • Lymph Nodes / immunology*
  • Male
  • Middle Aged
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology*
  • Sarcoidosis, Pulmonary / genetics
  • Sarcoidosis, Pulmonary / immunology*
  • Statistics as Topic


  • Antigens
  • Receptors, Antigen, T-Cell