Lymphocytic infiltration and HLA-DR expression of salivary glands in bone marrow transplant recipients: a prospective study

Lymphocytic infiltration and epithelial HLA-DR expression of lip salivary glands were studied by means of an immunohistoenzymatic staining technique in patients undergoing repeated lip salivary gland biopsies before, and 12, 26, 52 and 104 weeks after bone marrow transplantation (BMT). Within 12 weeks of transplantation, lymphocytes, mainly of the anti-Leu3a+ T 'helper' phenotype, were seen infiltrating the salivary glands of all the patients, reaching a maximum between 26 and 52 weeks. Epithelial HLA-DR expression, present at the 12th week after BMT, was seen close to the lymphocytic infiltrates in all the specimens. Two years after BMT, lymphocytic infiltrates and epithelial HLA-DR expression were still noted in about half of the specimens but not seen in the remaining ones. No correlations were found between immunohistopathology and earlier or persistent chronic graft-versus-host disease or immunosuppressive treatment. The significance of the findings as well as their resemblance to idiopathic connective tissue diseases, notably Sjögren's syndrome, are discussed.