MURINE AUTOIMMUNE EXOCRINOPATHY - THE MINOR SALIVARY-GLAND NETWORK SHOWS A DICHOTOMOUS PATTERN OF HISTOPATHOLOGIC INVOLVEMENT

The minor salivary gland network of the MRL/1 mouse was investigated i n a kinetic study and compared with the major submandibular gland. We report that minor salivary glands adopt two mutually exclusive pattern s of inflammatory lesions depending on the gland. The first pattern is characteristic of human Sjogren's syndrome. It developed during the s econd month, affected 89% of the animals over 20 weeks old, and consis ted of an accumulation of mononuclear cells around the duct system. On ly the anterior buccal gland (ABG) showed this pattern, which is share d by the major salivary glands. The ratio of CD4+ to CD8+ cells was th e same in lesions and in healthy tissue. No neutrophils were found in these lesions. The second pattern affected all the minor salivary glan ds except the ABG, These lesions were never observed before the age of 20 weeks and affected 38% of MRL/1 mice between the ages of 10-32 wee ks, In this pattern, neutrophils were frequently found, but mainly gat hered at the periphery of the gland lobules, That a systemic immunoreg ulatory defect may be expressed as two different patterns of histopath ology in the minor salivary glands suggest that the network behaves as a dichotomous entity depending on particular microenvironmental influ ences.