Abstract
Frozen sections of the labial biopsies from 18 patients with Sjögren's syndrome (SjS) were studied with a panel of monoclonal antibodies identifying T cells, B cells, macrophages, and their subsets in order to characterize the immunocompetent cells in the salivary glands. T cells were predominant cells in the specimens with mild lymphocytic infiltrations. However, both T cell-foci and B cell-foci surrounding the ducts or acini were observed in the specimens with marked lymphocytic infiltrations. Ratio of B cells to T cells increased in accordance with the degree of lymphocytic infiltration. CD4-positive T cells (inducer/helper T cells) were more predominant than CD8-positive T cells in almost of all cases. CD4-positive T cells frequently showed focal accumulations, while CD8-positive T cells (suppressor/cytotoxic T cell) were diffusely scattered. In almost of all cases, B cell foci were surrounded by or intermingled with CD4-positive T cells. Phenotypes of the cells in B cell foci varied among the cases. CD23 (B6)-positive B cells (activated B cells) were observed in a part of B cell foci in the cases with severe lymphocytic infiltration, while resting B cell foci (CD21-positive) were also observed in the same foci. CD23-positive B cells were close to ducts and a part of them weakly expressed B cell activation antigen (B5) simultaneously. On the other hand, CD14 (monocyte/macrophage antigen)-positive cells were scattered in the interstitium and also positive for HLA-DR antigen. Expression of HLA-DR antigen were also detected on the epithelial cells in the ducts and acini, and on the majority of infiltrating T cells. Intensity of the expression of HLA-DR antigen varied among the cases. These findings indicate that T cells and a part of B cells of the salivary gland in patients with SjS were activated, and might suggest that immune responses between T cells and HLA-DR-positive cells play an important role in the disordered immunoregulation in SjS.
