Lymphocytic infiltrations of lip salivary glands in bone marrow recipients. A model for the development of the histopathological changes in Sjögren's syndrome?

By use of a PAP staining technique, the immunohistopathology in repeated biopsies from the lip salivary glands (LSGs) from patients undergoing bone marrow transplantation (BMT) was studied. In the previously normal LSGs, focally arranged lymphocytes and adjacent epithelial DR-expression appeared within 12 weeks post BMT, reaching a maximum between 26 and 52 weeks post BMT. Two years post BMT, lymphocytic infiltrates and epithelial DR-expression were still present in half of the specimens but were not seen in the remaining ones. The immunohistopathological changes seen in LSGs post BMT were indistinguishable from what has been found in Sjögren's syndrome. The appearance, and in some patients the subsequent disappearance, of the lymphocytic infiltrates and the epithelial DR-expression, without correlation to clinical symptoms of chronic graft-versus-host disease or immunosuppressive treatment, emphasizes the dynamic nature of lymphocytic infiltration of LSGs in BMT patients. Whether this also pertains to naturally occurring Sjögren's syndrome remains to be elucidated.