Macrophage containing factor XIII subunit a in salivary glands of patients with Sjögren's syndrome.

Minor labial salivary glands obtained at biopsy from patients with Sjögren's syndrome were investigated by immunomorphological methods for the presence of monocyte-derived macrophages. According to our observations published earlier the immunomorphological detection of factor XIII subunit a is a useful marker for recognizing cells of monocyte/macrophage lineage. Factor XIII subunit a was detected by a highly sensitive immunoperoxidase staining, and cells containing this coagulation enzyme were characterized by double immunofluorescence stainings. Factor XIII subunit a+ cells were found to be highly accumulated at the interface of normal tissue and peritubular infiltrate. In double immunofluorescence labelling systems factor XIII subunit a+ cells were simultaneously labelled by RFD7 and Dako-antimacrophage monoclonal antibodies. They also expressed HLA-DR antigen as revealed by a reaction with RFDR2 monoclonal antibody. The results suggest that monocyte-derived tissue macrophages are present in salivary glands of patients with Sjögren's syndrome and have a characteristic distribution. It can be assumed that they have a role in the demarcation of peritubular inflammation and thus have an effect on the progression of the disease.