Alteration of peripheral blood dendritic cells in patients with primary Sjogren's syndrome

Objective. We recently identified 3 fractions of human peripheral blood (PB ) dendritic cells (DC), including the monocyte-associated fractions 1 and 2 (CD1a+,CD11c+ and CD1a-,CD11c+, respectively) and the lymphoid-associated fraction 3 (CD1a-,CD11c-). We attempted to determine whether these fraction s were altered in Sjogren's syndrome (SS). Methods. We examined 23 patients with primary SS and 22 normal control subj ects. DC were purified from PB and analyzed by flow cytometry. Immunohistoc hemical staining of labial salivary glands of SS patients was performed wit h monoclonal antibodies against fascin, which is known to be specific for D C. Results. The total numbers of PB DC and fraction I DC were decreased in SS. Immunohistochemical staining demonstrated that fascin+,CD11c+,HLA-DR+ mono nuclear cells were present and scattered among numerous fascin-hyperfiltrat ing cells in SS patients. Interferon-gamma (IFN gamma)-producing Th1 cells were shown to be increased in both PB and salivary glands of patients, indi cating the presence of general IFN gamma -producing Th1 polarization in SS. Furthermore, numbers of Th1 cells were increased when naive T cells were c ocultured with fraction I DC in vitro. Conclusion. These findings suggest selective trafficking of fraction I DC i nto focal sites of inflammation and subsequent promotion of Th1 balance, su ggesting a novel pathogenesis of SS.