Morphometric study of histological changes in sublabial salivary glands due to aging process.

The sublabial salivary glands were studied by morphometric methods in 68 healthy volunteers to establish possible changes related to age in those tissue components that are affected in Sjögren's syndrome and connective tissue diseases (and which might stimulate Sjögren's syndrome). There was an increase in the amount of connective tissue and intralobular ducts with age and a corresponding decrease in acinar tissue. During the aging process changes in the intralobular ducts occurred: the outer and inner diameters of these ducts and the thickness of the epithelium decreased, but the ratio of the outer and inner diameters of the ducts remained constant. The amount of diffuse lymphoplasmacytic infiltrate and the vascularity of the tissue remains constant with age. In 15 of the subjects, however, discrete lymphocytic foci were seen and in six of these more than one focus/4 mm2 of salivary tissue was found, which has been described as suggestive of Sjögren's syndrome. The volume percentage of lymphocytic foci is constant during the aging process. The histological features commonly used to diagnose Sjögren's syndrome may occur in normal people, and false positive diagnoses will occur if these criteria are rigidly adhered to. Morphometry may provide more reliable criteria for distinguishing changes induced by inflammation and related to age which occur in salivary tissue.