Animal models of autoimmune disease have been successfully used to explore peripheral stem cell transfusion and bone marrow transplantation. Allogeneic marrow transplants have been shown to suppress lupus-like disease and experimental allergic encephalomyelitis. Autologous transplantation has also been successful in adjuvant arthritis. Operationally, these may be considered as graft versus autoimmunity effects. In humans, adoptive autoimmunity, in which the donor becomes apparent in the recipient, has been documented for myasthenia gravis and insulin dependent diabetes mellitus. Of 9 allogeneic bone marrow transplants for rheumatoid arthritis, 4 patients have done well for many years while one relapsed after 2 years. In 2 cases, autologous marrow transplant has been used specifically to treat autoimmune disease: one patient with CREST had only a transient response and one patient with myasthenia gravis had remission. While allogeneic bone marrow transplant is the most rational procedure, its use in nonmalignant disorders must be very carefully considered secondary to its toxicity and potential morbidity. The use of peripheral blood CD34+ cells with T cell depletion, may promise complete or partial longterm remission but results of this therapy need to be compared with other immunosuppressive combinations.