G J Prud'homme1, E Colle, A Fuks, A Goldner-Sauve, R D Guttmann. 1. Department of Pathology, McGill University, Department of Pediatrics, Montreal Children's Hospital, McGill Cancer Centre, and the Transplantation Unit, Royal Victoria Hospital, Montreal, PQ, Canada Insulin-dependent diabetes mellitus appears spontaneously in BB rats. Here Gerald Prud'homme and his colleagues discuss the evidence that the disease results from autoimmune processes in which self-reactive T lymphocytes have a central role.