1996 Volume 45 Issue 4 Pages 423-431
The major histocompatibility complex (MHC) class II antigens are well known to play an important role in antigen recognition by T cells and to influence the susceptibility to autoimmune diseases, including Sjögren's syndrome (SS). In this paper, an aberrant expression of HLA-DR antigen was examined immunohistochemically on acinar and ductal epithelial cells of labial salivary glands from 114 SS patients. Aberrant expression of HLA-DR antigens was frequently observed on acinar and ductal epithelial cells and differed markedly in different components of salivary gland tissue. Most acinar and intercalated ductal cells expressed HLA-DR antigen, while fewer intraloberlar ductal cells expressed the antigen. In contrast, most of the interloburlar ductal cells did not express HLA-DR antigen. The expression of HLA-DR antigen was closely associated with lymphocytic infiltration. The more extensive lymphocytic infiltration became, the more HLA-DR positive cells was observed. In some cases, the expression of HLA-DR antigens was observed not only in the areas with lymphocytic infiltration but also in areas where no infiltrating lymphocyte was observed.
Aberrantly expressed HLA-DR antigen enables acinar and ductal epithelial cells to play an antigenpresenting cell role for T cells, and thus might play an important role in precipitating an autoimmune response in SS.
