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

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.

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-gamma positive and IL-4 positive cells (Th1 and Th2, respectively).

Sarcoidosis patients had an increased number of CD4+ -IFN-gamma 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-gamma positive cells in IS and those in BALF in sarcoidosis patients (r = 0.685, p = 0.0006).

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.