EXPRESSION OF GRANZYME-A IN SALIVARY-GLAND BIOPSIES FROM PATIENTS WITH PRIMARY SJOGRENS-SYNDROME

Objective. To determine whether the destruction of salivary gland epit helial cells in Sjogren's syndrome (SS) could be mediated by granzyme A, a serine protease that is contained in the granules of activated ly mphocytes. Methods. We used in situ hybridization and polymerase chain reaction amplification to determine the expression of granzyme A mess enger RNA (mRNA) in salivary gland biopsy samples. Results. Granzyme A mRNA expression was detected in salivary glands from SS patients, but not in those from normal controls. Granzyme A mRNA content was signif icantly correlated (P < 0.001) with the size of lymphocytic infiltrate s in the salivary glands and with the clinical activity of the disease . Conclusion. Cells that express granzyme A mRNA may play a role in th e destruction of the target organ (i.e., the salivary gland) in patien ts with SS. The strong association of granzyme A mRNA expression and l arger lymphoid infiltrates in the patients) salivary glands suggests t hat granzyme A mRNA is expressed at a relatively late stage of the loc al inflammatory process. Therapies designed to modulate or block granz yme A induction and action should be investigated in SS patients.