Histopathological and immunohistochemical profile in primary Sjögren's syndrome

Sjögren's syndrome (SS) is an autoimmune disease characterized by hypofunction of the salivary and lachrymal glands. Main clinical features of SS are sicca symptoms, due to the altered glandular function. Also, in advanced stages, bilateral swelling of the parotid glands can be noted, indicative of severe glandular involvement. Phenotypic expression of various mononuclear cells present in the affected tissue offers additional insight into cellular proliferation, survival, migration, antibody secretion and also the potential of forming tertiary lymphoid tissue, i.e., germinal centers. The main objective of the present study was to evaluate various autoimmune activity patterns present in salivary glands by means of immunohistochemistry (IHC) analysis. The study group comprised of 10 primary SS patients, with various degrees of lymphocytic infiltrates confirmed on minor salivary gland (MSG) biopsy. We could identify both morphological changes, i.e., ductal system abnormalities or increased interstitial fibrosis, and immunological patterns associated with SS pathogenesis. CD3+ T-cells displayed a more intense reaction in specimens with mild to intermediate focus score (FS) grade. Specimens with important CD20+ B-cell component of lymphocytic infiltrate were associated with intermediate and severe FS grade. Specimens showed varying degrees of CD68+ cells, with more intense IHC reactions in slides displaying a more advanced mononuclear infiltration. Immunoreactivity was strong for both MMP-2 and MMP-8 matrix metalloproteinases, throughout the gland, in areas of acini, without it being linked with proximity of mononuclear cell infiltration. We could also establish some correlations between the degree of lymphocytic infiltration and clinical profile.