Th1/Th2 cell distribution in pulmonary sarcoidosis.

Cytokines released by T lymphocytes activated in the course of sarcoidosis, e.g., interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), indicate the presence of Th1 cells leading to the question of Th1/Th0/Th2 balance in sarcoidosis. The aim of this study was to evaluate Th-like cytokine patterns in different compartments of the body, i.e., peripheral blood, pulmonary parenchyma, and bronchoalveolar lavage (BAL), of patients with pulmonary sarcoidosis by comparing cytokine gene expression of 167 T-cell clones derived from the above-mentioned compartments. Seventy-nine blood, 49 transbronchial biopsy, and 39 BAL clones were analyzed using polymerase chain reaction to identify the respective gene transcripts. The majority of CD4+ and CD8+ blood cells exhibited intermediate cytokine profiles (63.3%) without shifts to either side of the spectrum (6.3% Th1, 5.1% Th2). Lung parenchyma cells shifted to the Th1 side of the spectrum: 26.5% of the cells were of Th1 or of intermediate type (between Th1 and Th0), whereas only 8.1% of the cells were of Th2 or of intermediate type (between Th0 and Th2). CD8+ parenchyma cells were evenly distributed. From BAL only CD4+ clones could be generated with shifts to both ends of the spectrum. Thus, our data provide evidence that in sarcoidosis, at the site of granuloma formation, an accumulation of Th1 cells as well as of intermediate (between Th1 and Th0) cell types occurs, whereas in the alveolar lumen, high numbers of Th1 and Th2 cells with a simultaneous decrease of Th0 cells can be observed.