Cytokines such as interferon (IFN)-?? and TNF-?? may enhance the antigen-presenting function of epithelial cells or, in the case of IFN-??, induce apoptosis of salivary gland epithelial cells (SGECs), through up-regulation of the Fas protein, a cell surface receptor whose activation leads to programmed cell death.15 A recently published study of the expression of CD40 protein (associated with B-ce