Th1/Th2 cytokine pattern in bronchoalveolar lavage fluid and induced sputum in pulmonary sarcoidosis

BACKGROUND: Sarcoidosis is thought to be a T-helper type 1 cytokine (Th2 cytokine) mediated disorder. Induced sputum (IS) has been proposed as a useful non-invasive method, mainly for the assessment of the airway diseases. The aim of this study was to explore induced sputum (IS) CD4(+)Th1 T-lymphocyte subpopulation and to compare them with those of bronchoalveolar lavage fluid (BALF) in patients with sarcoidosis. METHODS: We studied prospectively 21 patients (12 female, 9 male) of median age 46 yr (range, 25–65) with sarcoidosis and 10 normal subjects (5 female, 5 male) of median age 39 yr (range, 26–60). IS was performed with hypertonic saline solution using an ultrasonic nebulizer. BALF was performed within 10 days of IS. After stimulation of sputum lymphocytes with phorbol-myristate-acetate, we used double immunocytochemical methods to identify CD4(+ )IFN-γ positive and IL-4 positive cells (Th1 and Th2, respectively). RESULTS: Sarcoidosis patients had an increased number of CD4+ -IFN-γ producing cells in IS (p = 0.003) and BALF (p = 0.01) in comparison with normal subjects. No significant differences were detected between CD4+ -IL-4 cells in BALF (p = 0.053, NS) and IS (p = 0.46, NS) between sarcoidosis patients and healthy controls. The ratio of Th1 to Th2 cells in BALF and IS was statistically different in sarcoidosis when compared with normal subjects (p = 0.007 in BALF and IS). A significant correlation was found between CD4+ IFN-γ positive cells in IS and those in BALF in sarcoidosis patients (r = 0.685, p = 0.0006). CONCLUSION: These data suggests that a Th1-like cytokine pattern can be observed in CD4+ T-lymphocytes in IS in patients with pulmonary sarcoidosis. Further studies are needed to explore the value of IS vs BALF in the follow-up of these patients.