title: The CD4/CD8 ratio in BAL fluid is highly variable in sarcoidosis.
abstract: Patients with pulmonary sarcoidosis frequently have increased numbers of lymphocytes and a high ratio of CD4+ to CD8+ T-lymphocytes (CD4/CD8 ratio) in bronchoalveolar lavage (BAL) fluid. Some investigators have suggested that these parameters can be used to distinguish sarcoidosis from other types of interstitial lung disease with a high degree of reliability. However, we hypothesized that the BAL CD4/CD8 ratio measured during the initial diagnostic evaluation of patients with biopsy-proven sarcoidosis is highly variable. BAL lymphocytes were analysed via flow cytometry to determine the CD4/CD8 ratio in a population of 86 patients with histological and clinical evidence of sarcoidosis, who underwent BAL as part of their initial diagnostic evaluation. In these patients, the CD4/CD8 ratio ranged 0.5-37.3, with a median value of 3.35 (mean 6.49). The CD4/CD8 ratio was greater than 4 in only 36 (42%) subjects. Ten patients (12%) had a CD4/CD8 ratio less than 1. The distribution of CD4/CD8 ratios was similar in the presence or absence of BAL lymphocytosis. In conclusion, the CD4/CD8 ratio in bronchoalveolar lavage fluid is highly variable in biopsy-proven sarcoidosis. Bronchoalveolar lavage lymphocyte subset determination is a diagnostic test with low sensitivity for this disease.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Dept of Medicine, University of Washington Medical Center, Seattle 98195-6522, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Kantrow
authors.forename: K C
authors.initials: KC
authors.lastname: Meyer
authors.forename: P
authors.initials: P
authors.lastname: Kidd
authors.forename: G
authors.initials: G
authors.lastname: Raghu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D017565:Sarcoidosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity