Ia-like antigens on T-cells and their subpopulations in pulmonary sarcoidosis and in hypersensitivity pneumonitis. Analysis of bronchoalveolar and blood lymphocytes

Am Rev Respir Dis. 1985 Mar;131(3):337-42. doi: 10.1164/arrd.1985.131.3.337.


We investigated the expression of Ia antigens on T-cells from lung and blood, as a sign of T-cell activation, in 17 patients with active pulmonary sarcoidosis, 12 patients with inactive sarcoidosis, 9 patients with hypersensitivity pneumonitis, and 10 normal control subjects. Lymphocyte subsets were identified by mouse monoclonal antibodies using a peroxidase-antiperoxidase method. Patients with active sarcoidosis and patients with hypersensitivity pneumonitis had a significant increase in Ia+ T-cells in bronchoalveolar lavage fluid compared with that in patients with inactive sarcoidosis and that in control subjects (p less than 0.01). Blood T-cells from the same patients did not show this sign of activation. The highest numbers of Ia+ T-cells were recovered from the lungs of patients with hypersensitivity pneumonitis, indicating the high state of activation of immunoregulatory T-cells in this disease. Additional analysis revealed that in sarcoidosis, Ia+ lung T-cells were exclusively of the OKT4+ helper phenotype, whereas in hypersensitivity pneumonitis, OKT4+ helper as well as OKT8+ suppressor lung cells expressed in part Ia antigens. These observations suggest that different T-cell subpopulations are activated in sarcoidosis and in hypersensitivity pneumonitis.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Alveolitis, Extrinsic Allergic / blood
  • Alveolitis, Extrinsic Allergic / immunology*
  • Bronchi / cytology
  • Bronchoscopy
  • Female
  • Histocompatibility Antigens Class II / analysis
  • Histocompatibility Antigens Class II / immunology*
  • Humans
  • Lung Diseases / blood
  • Lung Diseases / immunology*
  • Male
  • Middle Aged
  • Pneumonia / blood
  • Pneumonia / immunology
  • Pulmonary Alveoli / cytology
  • Sarcoidosis / blood
  • Sarcoidosis / immunology*
  • T-Lymphocytes / analysis
  • T-Lymphocytes / immunology*
  • T-Lymphocytes, Helper-Inducer / immunology
  • T-Lymphocytes, Regulatory / immunology
  • Therapeutic Irrigation


  • Histocompatibility Antigens Class II