[Peripheral blood dendritic cell dysfunction in patients with Sjögren's syndrome]

The function of dendritic cell (DC), that has the strongest antigen-presenting ability, was investigated for the purpose of clarifying immune abnormalities in Sjögren's syndrome (SS) from the point of view of antigen-presenting cells. DCs were separated from peripheral blood of SS patients, and mixed lymphocyte reaction (MLR) with DCs was observed to examine the function of DC. Autologous MLR (AMLR), which was induced by mixed culture of DCs with autologous T cells, significantly decreased in SS patients (p < 0.01). Allogeneic MLR (alloMLR), which was induced by mixed culture of DCs with allogeneic T cells, also decreased in SS patients, suggesting the presence of DC dysfunction. Cell surface expression rates of HLA-DR, CD 80, and CD 83, which are a first signal of cell surface antigen presentation, a second signal, and a specific antigen of DC, respectively, were then examined. Among HLA-DR-positive cells, CD 80-positive cells and CD 83-positive cells increased in SS patients, compared with normal subjects (p < 0.0003 and p < 0.00009, respectively). From these results, it was inferred that SS patients have not only DC dysfunction, but abnormalities in cell surface antigens as well.