A histopathological study of lymphoepithelial island formation in labial salivary glands in patients with primary Sjögren's syndrome.

The proliferative status of lymphoepithelial islands in the labial salivary glands of primary Sjögren's syndrome (pSS) patients was investigated by counting the number of argyrophilic nucleolar organizer regions (AgNORs) in epithelial cells constituting the islands. The islands were classified into four groups and evaluated in terms of total area and three discrete zones of the islands. In each pSS group, the mean AgNOR number per total island epithelial cell nucleus was significantly higher than in control ductal epithelial cells. The zonal AgNOR number fluctuated during the process of island formation but became more uniform as the islands developed. Furthermore, statistically significant trends among the four pSS groups were observed in the ratio of T lymphocytes, B lymphocytes and plasma cells surrounding the islands. The results indicated that the islands are highly proliferative once island formation begins and that zonal island cell proliferation may be associated with the inflammatory cells.