Activation of T cell subsets in the peripheral blood of patients with Sjögren's syndrome. Multicolor flow cytometric analysis.

Using 3-color flow cytometry, we determined the proportions of activated T cells (DR+), including CD4+ cells, CD8+ cells, and their subsets, in the peripheral blood of 17 patients with Sjögren's syndrome (SS). Activated T cells were significantly increased in CD4+ cells, CD8+ cells, and T suppressor inducer (CD4+, Leu-8+), T helper (CD4+, Leu-8-), and T cytotoxic (CD8+, CD11-) subsets, but not the T suppressor/natural killer subset (CD8+, CD11+), in patients with SS as compared with the controls. Furthermore, the proportions of activated T cells in the CD4+, Leu-8- subset, the CD8+ subset, or the CD8+, CD11- subset showed a positive correlation with serum gamma globulin levels in the SS patients. Our findings suggest that a certain immunoregulatory balance between T helper and T suppressor activities is maintained in SS patients, although this balance seems to occur at highly activated levels, and that quantitative changes of some lymphocyte subsets are important factors in maintaining this balance. We discuss the possibility that CD4+, Leu-8+ cells recirculate into peripheral lymph nodes, while CD4+, Leu-8- cells migrate into inflammatory tissues such as salivary glands, since the Leu-8 antigen is reported to be a homing receptor in peripheral lymph nodes. This process might be accelerated in SS, and each T cell subset may further participate in immunologic activation in the lymph nodes or target tissues.