Stem cell transplantation for severe autoimmune diseases: new proposals but still unanswered questions.

An extensive series of experimental investigations has shown that both inherited and induced autoimmune diseases in laboratory animals may be transferred and, conversely, cured by stem cell transplantation. In man, the evidence is mainly anecdotal, originating both from the transmission of autoimmune conditions following allogeneic BMT from carrier donors to non-autoimmune recipients transplant-requiring diseases, and from the resolution of autoimmune diseases (mainly rheumatoid arthritis) of the recipients after allogeneic BMT from healthy donors. Will it be possible to cure severe autoimmune diseases with powerfully immunosuppressive conditioning regimens followed by the administration of hematopoietic stem cells? If the reconstitution of a naive immune system is necessary, allogeneic stem cells will be necessary, but the procedure is still saddled with its attending problems, with TRM in the foreground. When utilizing autologous stem cells in conjunction with TCD the patients' tolerance will be significantly better, but remissions are to be anticipated rather than cures. However, some special manipulations may be expected to ameliorate results in those selected autoimmune patients not or badly responding to conventional immunosuppressive therapy, for whom this type of treatment can be offered.