Immunohistochemical and ultrastructural characterization of autoimmune sialoadenitis in aging BDF1 mice.

To further the understanding of the immunopathologic mechanisms involved in spontaneous autoimmune sialoadenitis of aging BDF1 mice, immunohistochemical and ultrastructural studies were undertaken. Eighteen of 19 aging BDF1 mice, 23-27 months of age, developed sialoadenitis spontaneously. By light and electron microscopy, it was observed that the submandibular gland lesion was characterized by mononuclear cell infiltration in the periductal and perivascular areas often accompanied by parenchymal destruction. Immunohistochemically, T cells predominated. The ratio of CD4+ to CD8+ T cells ranged from 0.5:1 to 2.9:1, with an average of 1.4:1. It seems likely that not only CD4+ cells, but also CD8+ cells, play a major role in submandibular gland inflammatory reactions of aging BDF1 mice.