HLA-DR expression by labial minor salivary gland tissues in Sjögren's syndrome

Minor salivary gland biopsy specimens from patients with Sjögren's syndrome (primary and secondary) and from normal controls were examined with the four step biotin-avidin-immunoperoxidase assay. The composition of the infiltrating cells was similar in patients with both primary and secondary Sjögren's syndrome, consisting primarily of T lymphocytes with predominance of T helper/inducer cells. B lymphocytes (Leu-14) were approximately 20-35% of the infiltrating lymphocytes, while only a few OKM1 (monocytes/macrophages) cells and Leu-7+ (natural killer; NK) cells were observed. The majority of infiltrating lymphocytes expressed HLA-DR antigens. In the biopsy specimens of the controls there were no infiltrates; the scattered lymphocytes, however, were also predominantly T lymphocytes. Finally, the glandular epithelial cells (ducts and acini) were inappropriately expressing HLA-DR antigens, in contrast with controls where minimal HLA-DR expression was found.