Intracellular cytokine repertoire in different T cell subsets from patients with sarcoidosis

Background-Pulmonary sarcoidosis is characterised by a mononuclear alveolit is with a predominance of CD4+ T cells and macrophages. We determined the i ntracellular expression of interferon (IFN)gamma, interleukin (IL)-2, tumou r necrosis factor (TNF)alpha, IL-4, IL-5 and IL-10 in CD4+ and CD8+, naive and memory lymphocytes from blood and bronchoalveolar lavage (BAL) fluid us ing three colour flow cytometry. Methods-Eighteen untreated patients with pulmonary sarcoidosis were evaluat ed and stratified according to whether they had acute or chronic disease. Results-Significantly more T cells expressed Th1 than Th2 type cytokines in both BAL fluid and peripheral blood samples, regardless of clinical presen tation. Significantly greater proportions of T cells secreted Th1 type cyto kines in BAL fluid than in peripheral blood. Thl type cytokines were more f requently expressed by peripheral and alveolar T cells in acute disease tha n in chronic disease. There were no significant differences between CD4+ an d CD8+ T cells. Concerning naive and memory lymphocytes, significantly high er CD45RO:CD45RA ratios were found in BAL fluid than in blood, and increase d expression of Th2 type cytokines was found in peripheral compared with al veolar memory T cells. Conclusions-Our data support the immunopathogenetic concept of Th1/Th2 imba lance and compartmentalisation in pulmonary sarcoidosis and suggest that th e cytokine patterns change during the course of disease. Expression of Th2 type cytokines in memory lymphocytes is decreased in the alveolar compartme nt compared with peripheral blood.