SUMMARYWe evaluated possible modes of epithelial cell destruction and restoration in minor salivary gland biopsies from patients with SS. Minor salivary gland biopsies from 10 primary Sjögren's syndrome (pSS) patients and eight control individuals were evaluated by immunohistochemical staining for the expression of apoptosis-related molecules, substances released by activated cytotoxic T cells, as well as proteins involved in epithelial cell repair. The results were analysed by computer screen analysis and they were expressed as average percentages. Apoptosis-promoting molecules, Fas antigen and Fas ligand were observed in ductal and acinar epithelial cells as well as in infiltrating mononuclear cells of minor salivary glands from SS patients in comparison with control biopsies. Bax protein, which acts as a death-promoter message, was expressed in the ductal and acinar epithelial cells and in mononuclear infiltrating cells of SS patients compared with control individuals, while Bcl-2, an inhibitor of apoptosis, was primarily found in the lymphocytic infiltrates. In situ DNA fragmentation assay (TUNEL) revealed that epithelial cells were apoptotic in patients with SS compared with control subjects. Immunohistochemical staining for perforin and granzyme B, released from granules of activated cytotoxic lymphocytes, revealed their presence in lymphocytic infiltrates of patients with SS compared with control biopsies. pS2, a member of the trefoil protein family which functions as promoter of epithelial cell repair and cell proliferation, was expressed in epithelial cells in biopsies from SS patients. These studies suggest that the functional epithelium of minor salivary glands in patients with SS appears to be influenced by both intrinsic and extrinsic mechanisms of destruction, while a defensive mechanism of epithelial restoration seems to be active.

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Abstract. Accumulating evidence suggests that the acetylation and deacetylation of histones play significant roles in transcriptional regulation of eukaryotic cells. The balance between acetylation and deacetylation is an important factor in regulating gene expression and is thus linked to the control of cell fate. The histone deacetylase inhibitors (HDIs) including the hydroxamic acids, such as suberoylanilide hydroxamic acid and pyroxamide, the benzamides MS-275 and CI-994 and the butyrate derivative 4-PBA are a new class of anti-neoplastic agents currently being evaluated in clinical trials. Moreover, new synthetic HDIs have been used recently in phase I and II clinical trials. Over the next few years experts believe that as first generation HDIs produce clinical benefits and second generation inhibitors are rationally designed with improved specificity, this class of drugs will emerge as a new way of cancer treatment. The first clinical studies have shown that histone hyperacetylation can be achieved safely in humans and that treatment of cancer with such agents seems to become possible. The use of HDIs, probably in association with classical chemotherapy drugs or in combination with DNA-demethylating agents, could be promising for cancer patients. Further evaluation is needed to establish the clinical activity of combination therapy using HDIs with cytotoxic drugs or differentiation induced agents.