title: Gamma/delta T lymphocytes in the blood of patients with sarcoidosis.
abstract: BACKGROUND
  Gamma/delta T lymphocytes are thought to have a role in granulomatous immune responses at peripheral sites of antigen contact such as the gut, skin and lung. The aim of this study was to determine if gamma/delta T lymphocytes are increased in the peripheral blood of patients with active sarcoidosis.
  
  
  METHODS
  Peripheral blood from 21 untreated patients with a new presentation of sarcoidosis (12M, 9F), 20 normal volunteers (12M, 8F), and 12 patients with cavitary pulmonary tuberculosis were subjected to Ficoll Hypaque separation and flow cytometry analysis using monoclonal antibodies to CD3, 4, 8, 25, HLA-DR and gamma/delta T cell receptor.
  
  
  RESULTS
  All patients with sarcoidosis had compatible chest radiographs and all were Mantoux negative in spite of previous BCG vaccination. In all but one patient histological examination showed non-caseating granuloma. There was no difference in the mean percentage or absolute numbers of gamma/delta positive peripheral blood lymphocytes between the three populations. Thirteen patients with sarcoidosis had an absolute lymphopenia and the mean percentage of CD3 positive peripheral blood lymphocytes in the group with sarcoidosis was lower than the other two groups. The percentage of CD25 and HLA-DR positive cells was higher in the group with sarcoidosis, supporting the fact that these patients had active disease.
  
  
  CONCLUSIONS
  Gamma/delta T lymphocytes are not increased in the peripheral blood of patients with sarcoidosis and are unlikely to have a role in the pathogenesis of this disease.
authors.affiliation: Department of Respiratory Medicine, Green Lane Hospital, Auckland 3, New Zealand.
authors.forename: M L
authors.initials: ML
authors.lastname: Wilsher
authors.forename: M
authors.initials: M
authors.lastname: Hallowes
authors.forename: N M
authors.initials: NM
authors.lastname: Birchall
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000032:analysis; D017565:Sarcoidosis, Pulmonary / Q000097:blood* / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000097:blood
chemical_list: D006684:HLA-DR Antigens; D015375:Receptors, Interleukin-2