Immunobiological studies on the alopecic (DEBR) rat.

The Dundee experimental bald rat (DEBR) has been proposed as an animal model of human alopecia areata, which is suspected of being an autoimmune disease. This study was carried out to establish whether the immunological changes observed in the lesional DEBR rat correlated with studies of human alopecia areata. The immune infiltrate was characterized using immunoperoxidase techniques on cryostat sections of vibrissa follicles. Indirect immunofluorescence was used to quantify the peripheral blood leucocytes. Some parallels were observed in the infiltration of human and DEBR rat follicles by T lymphocytes. In contrast, pre-lesional DEBR rat follicles, which are not available for investigation in human alopecia areata, were not penetrated by leucocytes and MHC class II antigens were expressed in the precortical region of the epidermal component of these follicles. Quantification of peripheral blood leucocytes showed significant increases in both T-lymphocyte subsets during lesional expression. We consider that the pre-lesional form of the rat may provide important information as a model for the pre-lesional and uninvestigated form of alopecia areata in man.