Higher cytotoxic capacity in peripheral blood of sarcoidosis patients (P3135)

Abstract BACKGROUND. Sarcoidosis is a granulomatous disease of unknown etiology, mainly affecting the lungs, where greatly increased numbers of CD4+ T cells typically are seen. However, CD8+ T cells can sometimes make up the majority of cells recovered by bronchoalveolar lavage (BAL). Previous studies have extensively studied Th1 cytokine-producing T cells and established their role in the pathological process. Little is however known about cytotoxic cells in sarcoidosis. METHODS: Peripheral blood (from 17 sarcoidosis patients and 11 healthy controls) and BAL fluid (from 19 patients and 4 controls) was obtained. Flow cytometric analysis of cell subsets was performed after staining with antibodies against the surface molecules CD3, CD4 and CD8 as well as antibodies against the cytotoxic intracellular mediators perforin, granzyme B and granulysine. The PBMC cytotoxic activity was quantified with the 51Cr release assay. RESULTS: Sarcoidosis patients had a significantly higher percentage of both perforin+ (p < 0.001) and granzyme B+ (p < 0.05) CD8+ T cells in blood. In BAL, however, a tendency in the opposite direction was seen. Higher cytotoxic activity was observed in PBMC from patients with sarcoidosis compared to controls. CONCLUSION: Cytotoxic cells, including CD8+ T cells, may be involved in the propagation or regulation of the inflammatory process in sarcoidosis, but further studies are needed to delineate their role in this disease.