Activation of peripheral blood lymphocytes in patients with primary Sjögren's syndrome.

The peripheral blood from 15 patients with primary Sjögren's syndrome and from 15 matched controls was examined for the presence of activated T and B lymphocytes, by using monoclonal antibodies directed to interleukin-2 (IL-2) and transferrin receptors, and to HLA-DR determinants. The number of circulating positive-T cells was significantly greater in the patients than in the controls, irrespective of disease activity. There were more of the CD8 cells than of the CD4 cells that expressed IL-2 receptors. There was a small but significant increase in activated B cells in the patients, since this population is virtually absent from the normal blood.