Evidence for Cellular Mediated Immunity in an Animal Model of Autoimmune Pituitary Disease

The anterior pituitary gland can be involved in an inflammatory reaction mediated by lymphocytes that leads to various degrees of dysfunction. In seven rabbits immunized with homologous pituitary tissue in complete Freund's adjuvant, a focal lymphocytic infiltrate, and increased fibrosis was observed in five. These changes were patchy in distribution and limited to the anterior pituitary. No inflammation was observed in five control animals. When incubated with pituitary extract, partially purified lymphocytes from four of the five animals with altered pituitary histology demonstrated a significant (p < 0.05) stimulation of 3H-thymidine incorporation. Measures of antipituitary antibodies using indirect immunofluorescence were negative in experimental as well as control animals. The present studies characterize the histologic changes and suggest that cellular immunity plays a role in the pathpgenesis of experimentally induced autoimmune pituitary disease.