Lymphocytotoxic antibody in Sjögren's syndrome

The autoimmune mechanism in Sjögren's syndrome (SjS) and the close association of this syndrome with systemic lupus erythematosus (SLE) have been suggested in several reports. Although the pathological significances of lymphocytotoxic antibody is obscure, possible roles of this antibody in the pathogenesis of autoimmunity have been speculated. The purposes of the present study were to demonstrate lymphocytotoxic antibody in sera of patients with SjS, and then to analyse various correlations of this antibody with clinical parameters of SjS. We detected cold-reactive lymphocytotoxic antibody not only in most (86.4%) of the patients with SLE, but also in many patients with SjS (51.6%; excluding SjS patients with SLE), rheumatoid arthritis (RA; 31.6%) and myasthenia gravis (MG; 36,4%), which are considered to be autoimmune diseases. On the other hand, lymphocytotoxic antibody was detected in only one (5.6%) of eighteen healthy persons. We also confirmed that the cold-reactive lymphocytotoxic antibody detected in SLE is 2-mercaptoethanol sensitive and T-lymphocytotoxic antibody. Frequent demonstration (50%) of this antibody even in SjS patients without any associated diseases supports the immunological basis of SjS as well as virological participation in SjS. Although this antibody did not significantly correlate with most of the clinical parameters in SjS patients, this antibody may become a hallmark as one of immunological abnormalities in SjS, even though it was produced by non-specific lymphocyte activation.