We analyzed activated T-cells in the peripheral blood (PB) of 29 patients with Sjögren's syndrome (SS: 13 I degrees-SS and 16 II degrees-SS patients) and 11 patients with rheumatoid arthritis (RA) by two-color flowcytometry using antibodies to antigens serially expressed on the cell surface after activation--interleukin-2 receptor (IL-2R), HLA-DR, T-lineage specific antigen (TLiSA-1) and very late antigen (VLA-1). The early and intermediate activation antigens, DR and TLiSA-1, were significantly increased in the PB of SS and/or RA patients. The proportions of activated T-cells were higher in CD8+ cells than those in CD4+ cells. T-cells expressing IL-2R or VLA-1, which appear in the very early or late stages of activation, were also increased in SS and/or RA patients. The results suggest that activated T-cells in the PB of both diseases might be recruited from continuously activated lymphoid organs, and that the activated cells migrate from PB into target tissues. In addition, the increase of activated T-cells in PB might be one of the causes of the deficient cell-mediated immunity reported in these patients.