LYMPHOID FOLLICLES IN THE GASTRIC-MUCOSA OF DOGS - DISTRIBUTION AND LYMPHOCYTE PHENOTYPES

The occurrence and distribution of lymphoid follicles within the stoma chs of 36 dogs that did not have macroscopic gastric lesions are prese nted. The dogs ranged in age from less than 1 year to over 13 years. T he number of follicles varied between the different regions of the sto mach, being most numerous (15.6 follicles cm(-2)) and uniform in size (about 1 mm in diameter) in the fundus. The number and size of follicl es in the antrum varied widely between dogs. Age-related changes in th e distribution of follicles were not found following simple linear reg ression analysis. The phenotypes of lymphocytes in gastric lymphoid fo llicles of nine dogs aged from less than 1 year to 5 years were determ ined using monoclonal antibodies specific for canine leucocyte antigen s and an indirect immunoperoxidase technique. The follicles had an org anized distribution of lymphocytes subsets in that a predominantly B c ell area contained some CD4 + cells and very few CD8 + cells and was a djacent to an area containing mostly T cells. Computer-assisted morpho metric analysis was used to quantify the overall presence of the vario us lymphocyte subpopulations. Follicles in the fundus and body regions possessed similar percentages of lymphocytes averaging 42%, 22% and 3 % of the area occupied by B cells, CD4 + and CD8 + cells, respectively . It is concluded that lymphoid follicles are a normal constituent of the canine gastric mucosa and possess a lymphocyte composition similar to that reported by others for solitary intestinal follicles.